Glossary

Crypto, blockchain, and SSP terms explained. 2,000+ entries from CoinMarketCap, Wikipedia, and the SSP team.

2157 terms

#

0x Protocol

0x is an Ethereum-based open-source platform for exchanging cryptocurrencies. It allows for the creation of features in a decentralized exchange (DEX), a wallet or a marketplace.

Moderate

123 Reg is a British domain registrar and web hosting company, founded in Britain in 2000 and now under the ultimate ownership of GoDaddy. The company claims to be the UK's largest accredited domain registrar and provides Internet services to small- and medium-sized business. From 2003 to 2017, 123 Reg was part of Host Europe Group (HEG). In April 2017, American hosting company GoDaddy acquired HEG for 1.69 billion euros.

1hr

Stands for data for the past 1 hour.

Easy

2-of-2 Multisig

A signing scheme where two independent private keys must each sign before a transaction is valid. SSP's default setup pairs your phone (SSP Key) and a second device (SSP Wallet); neither can spend on its own. The model removes the single-point-of-failure of one-key wallets without introducing a custodian.

Beginner

2018 Bitcoin bomb threats

On December 13, 2018, thousands of businesses, individuals, schools, news agencies, and other places throughout the United States, Canada, and Australia received emailed bomb threats, warning that a "mercenary" of the sender of the email had placed a bomb in the receiver's workplace and demanding that a ransom of $20,000 be sent to a Bitcoin address to prevent the bomb from being detonated. Six schools in Australia's capital city Canberra were evacuated after threats. The explosive stated to be used in the bomb, along with the Bitcoin address, varied between emails. Police departments in New York City, Oklahoma City, Massachusetts, and Calgary, among other areas of the United States and Canada, stated that the threats were likely not credible and that no explosive devices had been found in any of the threatened areas.

2020 Twitter account hijacking

On July 15, 2020, between 20:00 and 22:00 UTC, 69 high-profile Twitter accounts were compromised by outside parties to promote a bitcoin scam. Hackers used social engineering against Twitter employees to gain access to administrative tools, allowing them to post the tweets directly. The scam tweets asked individuals to send bitcoin currency to a specific cryptocurrency wallet, with the promise that money sent would be doubled and returned – within minutes, one account received over 320 deposits with a value of over US$110,000 before the scam messages were removed by Twitter.

The 80/20 rule, commonly known as Pareto Principle, states that 20% of your actions account for 80% of results.

Moderate

.

.brave

.brave is an internet domain that uses a blockchain-based top-level domain (TLD), launched by the web browser Brave in partnership with Unstoppable Domains.

$

$Libra cryptocurrency scandal

On February 14, 2025, Javier Milei, the president of Argentina, promoted a cryptocurrency project called $LIBRA. The price of the meme coin spiked following Milei's promotion but then suffered a severe price drop, leading to allegations of a rug pull scam and $251 million in losses for investors. This scandal has been dubbed Cryptogate. The Economist called it the "first big scandal" of Milei's presidency.

A

Aave

Aave is a decentralized finance protocol (DeFi) that enables the lending and borrowing of cryptocurrencies without the involvement of intermediary financial institutions.

Abenomics

Abenomics is the economic strategy implemented by Shinzo Abe of Japan and is comprised of three arrows: monetary policy, fiscal stimulus and structural reforms.

Easy

Abnormal Return

Abnormal return refers to the unusual profits from certain assets or securities over a specific time period.

Easy

A blockchain network that works on a hybrid consensus approach; both Proof of Work and Proof of Stake.

Easy

Affiliate

An affiliation is a connection between two firms where one company has a small stake in the other company. The concept also applies to the connection between two companies that are owned by the same parent company.

Easy

Affiliate Marketing

Affiliate marketing is a kind of promotion technique where a business pays a person or entity a commission for promoting their goods and services in order to increase sales.

Moderate

Algo-trading is an automated trading system where buy and sell orders are placed according to the rules of a computer program or algorithm.

Moderate

Algorand

Algorand is a proof-of-stake blockchain and cryptocurrency. Algorand's native cryptocurrency is called ALGO.

Algorithm

A process or set of rules to be followed in problem-solving or calculation operations, usually by a computer.

Easy

Algorithmic Contract Types Unified Standards

Algorithmic Contract Types Unified Standards (ACTUS) is an attempt to create a globally accepted set of definitions and a way of representing almost all financial contracts. Such standards are regarded as important for transaction processing, risk management, financial regulation, the tokenization of financial instruments, and the development of smart contracts for decentralized finance (DeFi) using blockchain technology. ACTUS is used as a reference standard by the Office of Financial Research (OFR), an arm of the US Treasury.

Algorithmic Market Operations (AMOs)

Algorithmic Market Operations (AMOs) automatically control the supply of algorithmic stablecoins while improving scalability, decentralization, and transparency.

Moderate

Algorithmic Stablecoin

An algorithmic stablecoin actually uses an algorithm underneath, which can issue more coins when its price increases and buy them off the market when the price falls.

Hard

Application Layer Transport Security (ALTS) is a Google-developed authentication and transport encryption system used for securing remote procedure call (RPC) within Google machines. Google started its development in 2007, as a tailored modification of TLS.

Amalgamation

An amalgamation is the merging of two or more organizations that should be recognized as separate legal entities by the jurisdiction’s laws.

Moderate

Amazon Coins

Amazon Coins were a digital payment method created by Amazon. They were discontinued in August 2025.

Amazon S3

Amazon Simple Storage Service (S3) is a scalable, high-speed, and inexpensive web-based cloud storage service to store and retrieve data anytime and anywhere.

Easy

AmbaCoin

AmbaCoin is the official cryptocurrency of Ambazonia. It was launched in 2018, and the ICO was from December 2018 to 2019. The Ambazonia Governing Council claims that all profits go towards their independence struggle and humanitarian aid. It is said to be backed by the "rich natural resources" of the breakaway region.

Amended Return

An amended return is a revised version of your original tax return.

Easy

AMLD5

The European Union’s 5th Anti-Money Laundering Directive (AMDL5) is an update to the union’s Anti-Money Laundering (AML) framework.

Moderate

Anarcho-capitalism

A political philosophy originally conceived by American economist Murray Rothbard that has now been embraced by many members of the crypto community.

Easy

Anchoring and Adjustment

Anchoring is the psychological phenomenon of having a preconceived idea of something and adjusting your decision-making around that preconceived notion.

Easy

Andrew Lee (entrepreneur)

Andrew S. Lee is an American entrepreneur and the founder of the VPN service Private Internet Access, which started in 2010. Lee has been the self-proclaimed King of the non-territorial Joseon Cybernation, recognized by Antigua and Barbuda as the successor state to Joseon and the Korean Empire in 2023,, and he is, in media, known as "Crown Prince of Korea" after being adopted by Yi Seok, a grandson of Emperor Gojong of Korea.

aNFT (Autonomous NFT)

aNFTs (autonomous NFTs) are non-fungible tokens that can be programmed to initiate their own transactions. Every aNFT is a self-contained, self-executing entity that can be designed to do any on-chain action in response to any on and off-chain condition.

Moderate

Angel Investor

A person who financially backs a new business venture or startup.

Easy

Animal Spirits

Animal spirits are the driving forces behind the economy that are not purely economic in nature but also include psychological factors, such as confidence and fear.

Easy

Anonymous matching is a matchmaking method facilitated by computer databases, in which each user confidentially selects people they are interested in dating and the computer identifies and reports matches to pairs of users who share a mutual attraction. Protocols for anonymous matchmaking date back to the 1980s, and one of the earliest papers on the topic is by Baldwin and Gramlich, published in 1985. From a technical perspective, the problem and solution are trivial and likely predate even this paper. The problem becomes interesting and requires more sophisticated cryptography when the matchmaker isn't trusted.

Anonymous remailer

A privacy-focused remailer is a server that receives messages with embedded instructions on where to send them next, and that forwards them while attempting to obscure their origin. There are cypherpunk remailers, mixmaster remailers, and nym servers, among others, which differ in their design and the level of privacy they were intended to provide. It is critical to understand that without integration with an anonymity network like Tor, these systems do not provide anonymity against powerful adversaries.

Anonymous veto network

In cryptography, the anonymous veto network is a multi-party secure computation protocol to compute the boolean-OR function. It was first proposed by Feng Hao and Piotr Zieliński in 2006. This protocol presents an efficient solution to the Dining cryptographers problem.

Anshel–Anshel–Goldfeld key exchange

Anshel–Anshel–Goldfeld protocol, also known as a commutator key exchange, is a key-exchange protocol using nonabelian groups. It was invented by Drs. Michael Anshel, Iris Anshel, and Dorian Goldfeld. Unlike other group-based protocols, it does not employ any commuting or commutative subgroups of a given platform group and can use any nonabelian group with efficiently computable normal forms. It is often discussed specifically in application of braid groups, which notably are infinite. The computed shared secret is an element of the group, so in practice this scheme must be accompanied with a sufficiently secure compressive hash function to normalize the group element to a usable bitstring.

ANSI ASC X9.95 Standard

The ANSI X9.95 standard for trusted timestamps expands on the widely used RFC 3161 - Internet X.509 Public Key Infrastructure Time-Stamp Protocol by adding data-level security requirements that can ensure data integrity against a reliable time source that is provable to any third party. Applicable to both unsigned and digitally signed data, this newer standard has been used by financial institutions and regulatory bodies to create trustworthy timestamps that cannot be altered without detection and to sustain an evidentiary trail of authenticity. Timestamps based on the X9.95 standard can be used to provide:authenticity: trusted, non-refutable time when data was digitally signed integrity: protection of the timestamp from tampering without detection timeliness: proof that the time of the digital signature was in fact the actual time an evidentiary trail of authenticity for legal sufficiency

Anti-dump/Anti-Dumping Policy

In the world of blockchain, the anti-dumping policy is a set of rules that protects investors from falling victim to a pump and dump scheme, in which a large number of tokens are purchased by an investor (whale) to boost the token’s value and then dumped at a much higher price, resulting in losses to investors who purchased the asset later.

Easy

Anti-Fragile

A quality attached to an asset that means it performs better when exposed to volatility and shocks.

Hard

Anti-Malware

Anti-Malware is a type of application software that prevents, detects, and removes malware from computers & electronic devices.

Easy

Anti-Money Laundering (AML)

A set of international laws enacted to curtail criminal organizations or individuals laundering money through cryptocurrencies into real-world cash.

Easy

Anti-replay

Anti-replay is a sub-protocol of IPsec that is part of Internet Engineering Task Force (IETF). The main goal of anti-replay is to avoid hackers injecting or making changes in packets that travel from a source to a destination. Anti-replay protocol uses a unidirectional security association in order to establish a secure connection between two nodes in the network. Once a secure connection is established, the anti-replay protocol uses packet sequence numbers to defeat replay attacks as follows: When the source sends a message, it adds a sequence number to its packet; the sequence number starts at 0 and is incremented by 1 for each subsequent packet. The destination maintains a 'sliding window' record of the sequence numbers of validated received packets; it rejects all packets which have a sequence number which is lower than the lowest in the sliding window or already appears in the sliding window. Accepted packets, once validated, update the sliding window.

Antitrust Law

Antitrust is a collection of laws that prohibits unfair competition or monopolistic practices by businesses.

Moderate

Antivirus

A piece of software designed to protect against malicious software and cyber attacks in general.

Easy

Antpool

Antpool is one of the largest Bitcoin mining pools and aggregates the computing power of many miners to increase the chance of solving a block and receiving the block reward.

Hard

Apeing

Apeing is when a cryptocurrency trader buys a token shortly after the token project launch without conducting thorough research.

Moderate

API

API stands for Application Programming Interface. It is a set of routines, protocols, and tools for building software applications. APIs specify how software components should interact, such as what data to use and what actions should be taken.

Easy

Application Layer

The top-most layer of a seven-layered OSI model.

Hard

Aptos Labs

Aptos Labs is a blockchain technology company headquartered in Palo Alto, California, known for developing the Aptos blockchain, a Layer-1 blockchain in the Web3 space. It was founded in 2021 by Avery Ching and Mo Shaikh, former employees of Facebook. Many other former Libra employees ended up joining Aptos Labs.

AR Token (Arweave)

AR is Arweave’s native token.

Easy

Arbitrage

Arbitrage is the practice of quickly buying and selling the same asset in different markets to take advantage of price differences between the markets.

Easy

Arbitrage Pricing Theory (APT)

The arbitrage pricing theory (APT) offers a framework for evaluating market efficiency and identifying arbitrage opportunities in financial markets.

Moderate

Arbitrageur

An arbitrageur is a type of investor who exploits pricing inefficiencies between two different markets.

Easy

Argon2

Argon2 is a key derivation function that was selected as the winner of the 2015 Password Hashing Competition. It was designed by Alex Biryukov, Daniel Dinu, and Dmitry Khovratovich from the University of Luxembourg. The reference implementation of Argon2 is released under a Creative Commons CC0 license or the Apache License 2.0.

Arkham (cryptocurrency exchange)

Arkham is an American company that operates a cryptocurrency exchange platform as well as a public data application that enables users to analyze blockchain and cryptocurrency activity.

Arm Virtual Machine (Qtum)

Qtum’s arm virtual machine allows users to execute applications in a decentralized manner.

Hard

Aroon Indicator

Aroon Indicator is used to identify the existence, changes, and corrective retracements and gauge the strength of an ongoing trend in financial markets.

Easy

Array controller based encryption

Within a storage network, encryption of data may occur at different hardware levels. Array controller based encryption describes the encryption of data occurring at the disk array controller before being sent to the disk drives. This article will provide an overview of different implementation techniques to array controller based encryption. For cryptographic and encryption theory, see disk encryption theory.

AS1 (networking)

AS1 is a specification about how to transport structured business-to-business data securely and reliably over the Internet. Security is achieved by using digital certificates and encryption.

AS2

AS2 is a specification on how to transport structured business-to-business data securely and reliably over the Internet. Security is achieved by using digital certificates and encryption.

Ascending Channel

Ascending channels are trend continuation patterns that have an ascending price action as their main characteristic.

Moderate

Assets under management measures the total market values of all the funds controlled by an individual or financial institution on behalf of their clients.

Easy

Astar Network

Astar Network is a blockchain that aims to become Polkadot's "smart contract hub" and serves as a parachain for Polkadot. The native token is "ASTR". The developers are members led by Sota Watanabe. Originally started under the name "Plasm Network" and rebranded as "ASTAR Network" in September, 2021。Mainnet opened to the public on January 17, 2022.

Aster (cryptocurrency exchange)

Aster is a decentralized cryptocurrency exchange and derivatives platform focused on perpetual futures trading. The platform supports trading across multiple blockchain networks and offers perpetual futures and other digital asset trading services.

Astroturfing

The practice of disguising marketing campaigns or otherwise sponsored messaging as the unprompted views of genuine community members.

Easy

Asynchronous

Events that do not occur simultaneously or at the same rate are referred to as asynchronous.

Moderate

Athena Bitcoin

Athena Bitcoin is a cryptocurrency company that operates over 4,000 bitcoin ATMs in the United States. Athena Bitcoin, Inc. is owned by Athena Bitcoin Global and traded as ABIT:PKC.

Atom Asset Exchange

Atom Asset Exchange (AAX) is a defunct cryptocurrency exchange that offered spot, perpetual contracts and savings products across a wide variety of digital assets, including Bitcoin, Ethereum and others.

Atomic Swap

The transfer of cryptocurrency from one party to another, without the use of an exchange or other intermediary.

Easy

AtomicDEX

AtomicDEX offers a cryptocurrency wallet and DEX in one application that is available for multiple platforms.

Hard

Attestation Ledger

An attestation ledger is an account book designed to provide evidence of individual transactions. It is generally used to “attest” that a financial transaction took place, or to prove the authenticity of transactions or products.

Easy

Attribute-based encryption

Attribute-based encryption is a generalisation of public-key encryption which enables fine grained access control of encrypted data using authorisation policies. The secret key of a user and the ciphertext are dependent upon attributes. In such a system, the decryption of a ciphertext is possible only if the set of attributes of the user key matches the attributes of the ciphertext.

Auction

An auction is a public sale through a bidding process where an asset is sold to the highest bidder.

Easy

Audit

An audit is a process where developers inspect the underlying code and/or algorithm that compose systems and applications.

Easy

Auditor

An auditor is a trained professional who conducts audits. They are typically employed by accounting firms or work within an organization's internal audit department.

Easy

Augmented Reality (AR)

Augmented Reality (AR) is an immersive experience that improves the value and usage of real-world items using computer-generated intuitive information sent through a variety of sensory modalities such as sound, touch, smell, and sight.

Moderate

Auroracoin

Auroracoin is a peer-to-peer cryptocurrency launched in February 2014 as an Icelandic alternative to bitcoin and the Icelandic króna. The unknown creator or creators use the pseudonym Baldur Friggjar Óðinsson. They stated that they planned to distribute half of auroracoins that would ever be created to all 330,000 people listed in Iceland's national ID database beginning on March 25, 2014, free of charge, coming out to ᚠ31.8 per person.

Authentication

Authentication is a process that confirms a user's identity using passwords, SMS codes, fingerprints, and other forms of ownership proofs before granting access to sensitive and/or personal information.

Easy

Authentication and Key Agreement

Authentication and Key Agreement (AKA) is a security protocol used in 3G networks. AKA is also used for one-time password generation mechanism for digest access authentication. AKA is a challenge–response based mechanism that uses symmetric cryptography.

AuthIP

AuthIP is a Microsoft proprietary extension of the IKE cryptographic protocol. AuthIP is supported in Windows Vista and later on the client and Windows Server 2008 and later on the server. AuthIP adds a second authentication to the standard IKE authentication which, according to Microsoft, increases security and deployability of IPsec VPNs. AuthIP adds support for user-based authentication by using Kerberos v5 or SSL certificates.

Authority Masternode (VeChain)

An authority masternode (AM) is a network-connected server that runs the VeChainThor full node program.

Hard

Authorization certificate

In computer security, an attribute certificate, or authorization certificate (AC) is a digital document containing attributes associated to the holder by the issuer. When the associated attributes are mainly used for the purpose of authorization, AC is called authorization certificate. AC is standardized in X.509. RFC 5755 further specifies the usage for authorization purpose in the Internet.

Automated Market Maker (AMM) [Updated]

An automated market maker (AMM) is a system that provides liquidity to the exchange it operates in through automated trading.

Hard

Autonomous Economic Agent (AEA)

A solution (software entity) by Fetch.ai and IOTA foundation that can take actions without external input using its own intelligence for the economic benefit of the owner.

Moderate

Autoroll

Autoroll refers to TV-signal decryption software that automatically updates a video receiver's or DVR/receiver's IDEA keys when the transmitting signal provider changes its block cipher algorithm.

An average selling price (ASP) refers to the amount at which a specific item is sold.

Easy

Axie Infinity

Axie Infinity is a blockchain game developed by Vietnamese studio Sky Mavis in 2018, known for its in-game economy which uses Ethereum-based cryptocurrencies. It has been called "a pyramid scheme that relies on cheap labor from countries like the Philippines to fuel its growth."

B

Back-to-Back Letters of Credit

Two letters of credit used consecutively to carry out a financial transaction through a third party are called back-to-back letters of credit.

Moderate

The BIS is an international financial institution that promotes global monetary stability.

Easy

Bank Run

A bank run occurs when most customers withdraw their cash from the bank out of fear of solvency and bankruptcy.

Easy

The human-readable address encoding used for native SegWit Bitcoin outputs, defined in BIP-173. Bech32 addresses start with 'bc1' on mainnet, use only lowercase letters and digits, and include an error-detection checksum that catches single-character typos. Taproot addresses use the updated Bech32m variant.

Moderate

Border Gateway Protocol Security (BGPsec) is a security extension of the Border Gateway Protocol defined in RFC 8205, published in September 2017. BGPsec provides to receivers of valid BGPsec UPDATE messages cryptographic verification of the routes they advertise. BGPsec replaces the BGP AS_PATH attribute with a new BGPsec_Path attribute.

Bid Price

The cost that someone is willing to pay for a security, asset, commodity, service, or contract is referred to as a bid price.

Easy

Bid-Ask Spread

Bid-ask spread is the difference between the highest price which a buyer is willing to pay for an asset as well as the lowest price that a seller is willing to accept.

Moderate

BidPay

BidPay was an online auction payment service website, established in 1999 by Steve Chin and Marek Bradbury that allowed auction buyers to purchase money orders online using their credit card. BidPay was purchased by First Data Corporation/Western Union in 2001 for an undisclosed sum. BidPay was rebranded as "Western Union Auction Payments" in 2003 which led to confusion with Western Union's wire transfer services; the online auction payment service reverted to the BidPay name in 2004. BidPay ceased operations on 31 December 2005 and was purchased for US$1.8 million in March 2006 by CyberSource Corporation, which announced its intention to relaunch BidPay. BidPay had over 4 million registered users worldwide at that time.

Big Tech

The four or five biggest technological corporations, particularly Facebook, Apple, Google, and Amazon, are referred to as "Big Tech" as they enjoy the biggest shares in their respective industries.

Easy

Bilateral key exchange

Bilateral key exchange (BKE) was an encryption scheme utilized by the Society for Worldwide Interbank Financial Telecommunication (SWIFT).

A bit is a basic unit of information in computing.

Easy

Bitchcoin

Bitchcoin is a non-fungible token (NFT) on the Ethereum blockchain. The project was launched in early 2015 as a fork of Bitcoin, several months before the launch of Ethereum. Bitchcoin was originally backed by the artist Sarah Meyohas' photography at a fixed rate of one token to 25 square-inches of one of the artist's photographs. This was one of the first instances of a physical work of art being put on a blockchain.

BitClout

BitClout was an open source blockchain-based social media platform. On the platform, users could post short-form writings and photos, award money to posts they particularly like by clicking a diamond icon, as well as buy and sell "creator coins". BitClout ran on a custom proof of work blockchain, and was a prototype of what can be built on DeSo. BitClout's founder and primary leader is Nader al-Naji, known pseudonymously as "Diamondhands".

Bitcoin

Bitcoin is the first decentralized cryptocurrency. Based on a free-market ideology, bitcoin was invented in 2008 when an unknown person published a white paper under the pseudonym of Satoshi Nakamoto. Use of bitcoin as a currency began in 2009, with the release of its open-source implementation. From 2021 to 2025, El Salvador adopted it as legal tender currency before revoking it. As bitcoin is pseudonymous, its use by criminals has attracted the attention of regulators, leading to its ban by several countries.

Bitcoin 3.0

Bitcoin 3.0 represents the next evolutionary phase of Bitcoin mining, characterized by its potential to become a responsible partner in both the energy and financial ecosystems.

Moderate

Bitcoin and politics

Bitcoin and politics influence each other in several ways. Governments of several countries use Bitcoin in various capacities, and some politicians use Bitcoin in their electoral programs.

Bitcoin ATM

A Bitcoin ATM is a kiosk that allows a person to purchase Bitcoin and other cryptocurrencies by using cash or debit card. Some Bitcoin ATMs offer bidirectional functionality, enabling both the purchase of Bitcoin and the sale of Bitcoin for cash. In some cases, Bitcoin ATM providers require users to have an existing account to transact on the machine.

Bitcoin ATM (BTM)

An automated teller machine (ATM or cashpoint) that allows the user to buy and sell Bitcoin.

Easy

Bitcoin buried in Newport landfill

In 2013, Welsh computer engineer James Howells mistakenly disposed of a laptop hard drive containing the private key for 8,000 Bitcoin in the Docksway landfill in Newport, Wales. Howells subsequently assembled a team of specialists and secured funding to excavate the site, but Newport City Council refused permission, citing the environmental impact of the search including dangerous gases, methane, asbestos, and toxic leachate. If the coins are discovered, Howells proposes distributing 30% of the proceedings among the council and the population of Newport.

El Salvador was the first country in the world to use bitcoin as legal tender, after it was adopted as such by the Legislative Assembly of El Salvador in 2021. It has been promoted by Nayib Bukele, the president of El Salvador, who claimed that it would improve the economy by making banking easier for Salvadorans, and that it would encourage foreign investment. In 2022, more Salvadorians had Bitcoin Lightning wallets than bank accounts.

Bitcoin Law

The Bitcoin Law was passed by the Legislative Assembly of El Salvador on 8 June 2021, giving the cryptocurrency bitcoin the status of legal tender within El Salvador after 7 September 2021. It was proposed by President Nayib Bukele. The text of the law stated that "the purpose of this law is to regulate bitcoin as unrestricted legal tender with liberating power, unlimited in any transaction, and to any title that public or private natural or legal persons require carrying out".

Bitcoin Misery Index (BMI)

The Bitcoin Misery Index (BMI) is used by investors as an investment tool that ranges from 0 to 100.

Easy

Bitcoin NFTs

Non-fungible tokens (NFTs) minted on Bitcoin-powered blockchains and secured by the Bitcoin network are known as Bitcoin NFTs.

Moderate

Bitcoin Pizza

Bitcoin Pizza refers to the infamous transaction where a guy, named Laszlo Hanyecz, paid 10,000 Bitcoins for two pizzas making it the first business transaction of Bitcoin in the real world.

Easy

Bitcoin protocol

The bitcoin protocol is the set of rules that govern the functioning of bitcoin. Its key components and principles are: a peer-to-peer decentralized network with no central oversight; the blockchain technology, a public ledger that records all bitcoin transactions; mining and proof of work, the process to create new bitcoins and verify transactions; and cryptographic security.

Bitcoin Satoshi Vision

Bitcoin Satoshi Vision (BSV) is a cryptocurrency that is a hard fork of Bitcoin Cash. Bitcoin Satoshi Vision was created in November 2018 by a group of individuals led by Craig Steven Wright, who has claimed since 2015 to be Satoshi Nakamoto, the creator of the original bitcoin.

Bitcoin scalability

Bitcoin scalability refers to the capability of the Bitcoin network to handle large amounts of transaction data on its platform. Records in the Bitcoin blockchain are limited in size and frequency to prioritize security and decentralization by keeping the cost of running a Bitcoin node affordable. With an average block creation time of 10 minutes and a block size limit of around 1 megabyte, the base layer processes an estimated 3.3 to 7 transactions per second.

Bitcoin Virtual Machine (BitVM)

BitVM, or Bitcoin Virtual Machine, is a proposed system described in a whitepaper by Robin Linus that allows complex computations and smart contracts to be executed on the Bitcoin network.

Hard

Bitcoiner

A person who is bullish on Bitcoin.

Easy

Bitcointalk

Bitcointalk is the most popular online forum dedicated to Bitcoin, cryptocurrency and blockchain technology.

Easy

Bitdeer

Bitdeer Technologies Group, or simply Bitdeer, is a cryptocurrency company and mining platform based in Singapore. Spun off from the bitcoin-mining chip producer Bitmain, Bitdeer is among the largest miners by computer power and focuses on blockchain and high-performance computing. Bitdeer's U.S. headquarters are located in San Jose, California. The company also operates in other U.S. states as well as Europe and Bhutan.

BitFlyer

bitFlyer is a Japanese cryptocurrency exchange headquartered in Tokyo. It was founded in 2014 and is one of the largest cryptocurrency exchanges in Japan.

BitFuFu

BitFuFu Inc. is a Bitcoin miner and mining services innovator headquartered in Singapore.

Bitget

Bitget is a centralized cryptocurrency exchange.

Bitkey

Bitkey is a digital wallet for bitcoin, available in the U.S. and 95 other countries. Launched in 2023 by Block, Inc., a company founded by Jack Dorsey, Bitkey began shipping in March 2024. It is a multisignature wallet, storing bitcoin independently of third-party cryptocurrency exchanges or custodial platforms.

Bitkub

Bitkub is a Thailand-based cryptocurrency exchange operated by Bitkub Online Co., Ltd. under its parent group Bitkub Capital Group Holdings. The company was founded in 2018 by Jirayut Srupsrisopa and was among the first exchanges to receive a digital asset license from Thailand’s Securities and Exchange Commission (SEC) in 2019.

BitLicense

A business license permitting regulated virtual currency activities, issued by the New York State Department of Financial Services.

Easy

Bitmart

BitMart is a digital asset trading platform that focuses on cryptocurrency trading, operated by bachi.tech in the Cayman Islands. It is known for a 2021 security breach in which two-thirds of its assets were stolen. It was the subject of the Federal Trade Commission's first cryptocurrency probe in 2022.

BitMEX

BitMEX is a cryptocurrency exchange and derivative trading platform. It is owned and operated by HDR Global Trading Limited, which is registered in the Seychelles.

Bitnation

Bitnation, or crypto nation, was a cryptocurrency-based project self-described as a "voluntary nation", wherein all citizens chose to be citizens, founded in 2014 by Susanne Tarkowski Tempelhof. A part of the process for becoming a citizen involved recording vital records, identity, and other legal events through the use of a smart contract on the Ethereum blockchain.

BitPass

BitPass was an American company that from 2002-2007 that developed an online payment system for digital content and services including micropayments. It was founded in 2002 by Kurt Huang and Gyuchang Jun. One of its best-known projects was the Mperia online music store catering to unsigned artists. The company shut down in 2007.

BitPay

BitPay is a Bitcoin payment service provider.

Easy

Bits

A commonly used unit, or subdivision, of a single Bitcoin.

Easy

Bitstamp

Bitstamp is a Luxembourg-based cryptocurrency exchange founded in 2011. Considered the world’s longest-running cryptocurrency exchange, its business operations are conducted from its registered headquarters in Luxembourg City, with a satellite office in Ljubljana.

Bitstream

Configuration data loaded onto an FPGA is called Bitstream.

Moderate

BitTorrent protocol encryption

Protocol encryption (PE), message stream encryption (MSE) or protocol header encrypt (PHE) are related features of some peer-to-peer file-sharing clients, including BitTorrent clients. They attempt to enhance privacy and confidentiality. In addition, they attempt to make traffic harder to identify by third parties including Internet service providers (ISPs). However, encryption will not protect one from DMCA notices from sharing illegal content, as one is still uploading material and the monitoring firms can merely connect to the swarm.

Bitvavo

Bitvavo is a Dutch cryptocurrency exchange founded in 2018 by programmers Tim Baardse, Jelle de Boer and business administrator Mark Nuvelstijn.

Bitwala

Bitwala is a Berlin-based cryptocurrency financial services company offering a self-custodial Bitcoin wallet, a Visa debit card, crypto trading, and crypto-backed loans. The company was founded in 2015 by Jörg von Minckwitz, Jan Goslicki, and Benjamin P. Jones. After operating briefly under the name Nuri from 2021 to 2022, the company returned to the Bitwala brand in late 2023 following insolvency proceedings.

Black Hat Hacker

Black hat hackers usually use malware to penetrate into computerized networks and systems to steal data.

Easy

Black Swan Event

A black swan event, also known as black swan occurrences, is a metaphor for an unexpected event that has a significant impact.

Easy

Black-box obfuscation

In cryptography, black-box obfuscation was a proposed cryptographic primitive which would allow a computer program to be obfuscated in a way such that it was impossible to determine anything about it except its input and output behavior. Black-box obfuscation has been proven to be impossible, even in principle.

Black-Scholes Model

In simple terms, it is a mathematical formula that gives the fair price of stock options, allowing investors to calculate whether they are overvalued or undervalued.

Easy

Blacker (security)

Blacker is a U.S. Department of Defense computer network security project designed to achieve A1 class ratings of the Trusted Computer System Evaluation Criteria (TCSEC).

BLAKE (hash function)

BLAKE is a cryptographic hash function based on Daniel J. Bernstein's ChaCha stream cipher, but a permuted copy of the input block, XORed with round constants, is added before each ChaCha round. Like SHA-2, there are two variants differing in the word size. ChaCha operates on a 4×4 array of words. BLAKE repeatedly combines an 8-word hash value with 16 message words, truncating the ChaCha result to obtain the next hash value. BLAKE-256 and BLAKE-224 use 32-bit words and produce digest sizes of 256 bits and 224 bits, respectively, while BLAKE-512 and BLAKE-384 use 64-bit words and produce digest sizes of 512 bits and 384 bits, respectively.

Blake-256

Used in Decred, Blake-256 is a hash algorithm designed by Jean-Philippe Aumasson, Luca Henzen, Willi Meier, and Raphael C.-W. Phan.

Hard

Blinding (cryptography)

In cryptography, blinding first became known in the context of blind signatures, where the message author blinds the message with a random blinding factor, the signer then signs it and the message author "unblinds" it; signer and message author are different parties.

BLISS signature scheme

BLISS is a digital signature scheme proposed by Léo Ducas, Alain Durmus, Tancrède Lepoint and Vadim Lyubashevsky in their 2013 paper "Lattice Signature and Bimodal Gaussians".

Block

A batch of validated transactions bundled together by a miner or validator and appended to the blockchain. Each block contains a cryptographic reference to the previous block, forming the chain. Bitcoin produces a new block roughly every ten minutes; Ethereum targets twelve seconds per slot.

Beginner

Blockchain analysis is the process of inspecting, identifying, clustering, modeling and visually representing data on a cryptographic distributed-ledger known as a blockchain. The goal of blockchain analysis is to discover useful information about different actors transacting in cryptocurrency. Analysis of public blockchains such as Bitcoin and Ethereum is typically conducted by private companies like Arkham Intelligence, Chainalysis, TRM Labs, Elliptic, Nansen, Blockpliance, Elementus, Dune Analytics, CryptoQuant, and Ormi Labs.

Blockchain as a service

Blockchain as a service (BaaS) is an enterprise-level software service that allows businesses to use cloud-based integration solutions to build, host and use their own blockchain apps, smart contracts and functions on the blockchain infrastructure developed by a vendor. Just like the growing trend of using software as a service (SaaS) where access to the software is provided on a subscription basis, BaaS provides a business with access to a blockchain network of its desired configuration without the business having to develop their own blockchain and build in-house expertise on the subject.

Blockchain Explorer

A blockchain explorer is simply a search engine allowing users to browse through blockchain records.

Easy

Blockchain game

Video games can include elements that use blockchain technologies, including cryptocurrencies and non-fungible tokens (NFTs), often as a form of monetization. These elements typically allow players to trade in-game items for cryptocurrency, or represent in-game items with NFTs. Blockchain games have existed since 2017, gaining wider attention from the video game industry in 2021, when several AAA publishers expressed an intent to include this technology in the future. Players, developers, and game companies have criticized the use of blockchain technology in video games for being exploitative, environmentally unsustainable, and unnecessary.

Blockchain Mutual Credit

Blockchain mutual credit is a framework within which stable cryptocurrencies can be derived from multilateral exchange networks.

Moderate

Blockchain oracle

A blockchain oracle is a third-party service for smart contracts. Oracles provide trusted information based on the outside-world sources to the on-blockchain smart contracts. An oracle typically encapsulates the real-world complexity outside of the blockchain. This provides different engineering advantages, chiefly that critical errors and potential points of failure are easier to mitigate off-chain than on-chain.

Blockchain privacy

Blockchain privacy describes how blockchain systems handle the confidentiality of transaction and record data. Many public blockchains can provide pseudonymity, while ledger transparency can allow transaction tracing through analysis of on-chain activity and related information. The persistence of ledger data can also create data-protection challenges in some applications, including questions about erasure and rectification rights where personal data are involved, and privacy characteristics vary depending on system design and use case.

Blockchain Transmission Protocol (BTP)

Blockchain Transmission Protocol (BTP) enables isolated blockchains to operate as a fully decentralized settlement layer by securely anchoring transactions using a protocol that is universal.

Moderate

Blockchain Tribalism

Blockchain tribalism refers to people in the blockchain or crypto community becoming ideologically aligned with a specific blockchain or crypto.

Moderate

Blockchain Trilemma

The blockchain trilemma is the set of three issues that plague blockchains: decentralization, security and scalability.

Hard

Blockchain-As-a-Service (BaaS)

BaaS offers the capabilities of blockchain technology to businesses but without the necessity of establishing and maintaining a dedicated blockchain framework.

Hard

Blockchain-based Service Network

The Blockchain-based Service Network (BSN) is a backend architecture in China for developing and managing blockchain-based applications, and is split into Chinese and International uses. BSN China, designed as the backbone of China's blockchain strategy, was established in 2018 and launched in 2020 by the State Information Center under the National Development and Reform Commission of China, China Mobile, China UnionPay, and a technology architect. BSN International operates under the Singapore-based BSN Foundation.

Blockchain-Enabled Smart Locks

Blockchain-enabled smart locks solve many security issues and can be locked or unlocked based on the state of a variable that is embedded in a smart contract.

Hard

BlockFi

BlockFi was a digital asset lender founded by Zac Prince and Flori Marquez in 2017. It was based in Jersey City, New Jersey. It was once valued at $3 billion.

Blocknots

Blocknots were random sequences of numbers contained in a book and organized by numbered rows and columns and were used as additives in the reciphering of Soviet Union codes, during World War II. The Blocknot consisted of a booklet of fifty sheets of 5-figure random additive, 100 additive groups to a sheet. No sheet was used more than once, thus the blocknots were in effect a form of one-time pad. The Soviet Unions highest grade ciphers that were used in the East, were the 5-figure codebook enciphered with the Blocknot book, and were generally considered unbreakable.

Blockscale

Intel Blockscale was a brand of crypto-mining accelerator ASIC sold by the U.S. chip manufacturer Intel. The Blockscale product debuted in June 2022, and was cancelled by Intel in April 2023. Intel has stated that it will continue to supply chips to existing customers until April 2024.

Blockverify

Blockverify is a startup that provides blockchain-based anti-counterfeit solutions mainly to customers in the supply chain industry. The company, which was founded by Paul Tanasyuk and Pavlo Tanasyuk in 2015, allows its users to track high-value goods throughout the supply chain in the hopes of delivering authentic products to its consumers.

Blockweave

Blockweave is a data storage protocol that builds upon blockchain architecture. It utilizes a unique interconnected structure linking each block to the previous block and a random older block.

Easy

Blockworks Inc

Blockworks is a U.S. based data and software company focused on crypto markets. It provides investor relations software, a data API, and a market research platform. The company is headquartered in New York City.

Bluesky Crypto Protocol

The Bluesky crypto protocol is a decentralized social network protocol, organized by Twitter, that allows several social networks to interact with other social networks, thanks to an open standard.

Easy

BNB Smart Chain (blockchain platform)

BNB Smart Chain (formerly Binance Smart Chain) is a public blockchain platform that uses a proof-of-stake consensus mechanism and provides smart contract functionality. The platform's native cryptocurrency is BNB. The system is part of the broader Binance ecosystem founded in 2017 by Changpeng Zhao and Yi He.

Bollinger Band

A tool developed by Bollinger to help in the recognition of systemic pattern recognition in prices; it is a band that is plotted two standard deviations away from the simple moving average, or exponential moving average in some cases.

Moderate

Bonding Curve

A bonding curve is a mathematical curve that defines the relationship between the price and the supply of a given asset.

Moderate

Bored & Hungry

Bored & Hungry is a cryptocurrency-themed fast food restaurant in Long Beach, California, from 2022 to 2024. It was the first concept from Food Fighters Universe, the world's first NFT restaurant group owned by restaurateur Andy Nguyen. The restaurant was marketed around the Bored Ape Yacht Club, a series of non-fungible tokens, and payment was initially accepted in both United States dollars and cryptocurrency. While the original restaurant closed in 2024, franchise operations exist in other countries.

Bored Ape

Bored Ape Yacht Club (BAYC), often colloquially called Bored Apes or Bored Ape, is a non-fungible token (NFT) collection built on the Ethereum blockchain with the ERC-721 standard. The collection features profile pictures of cartoon apes that are procedurally generated by an algorithm.

Börse Stuttgart

Börse Stuttgart is the sixth largest exchange group in Europe. It has strategic pillars in the capital markets business as well as in the digital and cryptocurrency business. Börse Stuttgart Group employs around 700 people at its locations in Stuttgart, Berlin, Frankfurt, Ljubljana, Milan, Stockholm, and Zürich and holds a total of 16 licences from regulatory authorities in Germany, Sweden and Switzerland.

Bots

Automated software that can carry out tasks such as cryptocurrency trades.

Easy

Bottleneck

A bottleneck refers to a point where capacity becomes restricted, creating congestion and slowing the overall performance.

Easy

Bounty

A cryptocurrency bounty is a reward users receive for performing tasks assigned by a given blockchain or project.

Easy

Branch number

In cryptography, the branch number is a numerical value that characterizes the amount of diffusion introduced by a vectorial Boolean function F that maps an input vector a to output vector . For the (usual) case of a linear F the value of the differential branch number is produced by:applying nonzero values of a to the input of F; calculating for each input value a the Hamming weight , and adding weights and together; selecting the smallest combined weight across for all nonzero input values: .

Brave Browser

Easy

BRC-20

Taking its cue from Ethereum's ERC-20, the Bitcoin blockchain's BRC-20 is an experimental token standard. Ordinals protocol supports the generation and transfer of fungible tokens.

Easy

BREACH

BREACH is a security vulnerability against HTTPS when using HTTP compression. BREACH is built based on the CRIME security exploit. BREACH was announced at the August 2013 Black Hat USA conference by security researchers Angelo Prado, Neal Harris and Yoel Gluck.

Breaking

In the world of cryptocurrencies, breaking the forward compatibility of cryptoassets is seen in hard forks of a cryptocurrency.

Easy

Brian Armstrong

Brian Armstrong is the founder of Coinbase, one of the largest cryptocurrency exchanges in the United States.

Easy

Bricklayer function

In cryptography, the bricklayer function is a part of a round function that can be decomposed into identical independent Boolean operations on the partitioned pieces of its input data, so called bundles. The term was introduced by Daemen and Rijmen in 2001.

Bridges

A blockchain bridge allows the seamless transfer of data or tokens between two different blockchain projects.

Moderate

Bring your own encryption

Bring your own encryption (BYOE), also known as bring your own key (BYOK), is a cloud computing security model that allows cloud service customers to use their own encryption software and manage their own encryption keys.

Broadcast encryption

Broadcast encryption is the cryptographic problem of delivering encrypted content over a broadcast channel in such a way that only qualified users can decrypt the content. The challenge arises from the requirement that the set of qualified users can change in each broadcast emission, and therefore revocation of individual users or user groups should be possible using broadcast transmissions, only, and without affecting any remaining users. As efficient revocation is the primary objective of broadcast encryption, solutions are also referred to as revocation schemes.

Broadcast to Allied Merchant Ships

Broadcast to Allied Merchant Ships (BAMS) was a protocol and system of broadcasts for Allied merchant ship convoys that was used during World War II to provide for the transmission of official messages to merchant ships in any part of the world. The BAMS system is designed for communication by the best employment of radio stations available.

Browser Extension

A browser extension is a plugin for an internet browser that adds additional features.

Easy

Brute Force Attack (BFA)

An attempt to crack a password or key through automated trial and error.

Moderate

BTCPay Server

BTCPay Server is a free and open-source, self-hosted Bitcoin payment processor created in 2017 by Nicolas Dorier. The software allows merchants to accept bitcoin payments directly to their own wallets rather than through a centralized processor, and supports both on-chain Bitcoin and Lightning Network payments.

BTCS Inc.

BTCS Inc. is an American blockchain infrastructure technology company that operates Ethereum validator nodes and provides staking services. The company trades on the Nasdaq under the ticker symbol "BTCS" and is headquartered in Silver Spring, Maryland.

Bubble

When an asset is traded at a price exceeding that asset's intrinsic value.

Easy

Bug Bounty

A reward offered for the identification of vulnerabilities in software.

Easy

Bug Exploit

A bug exploit is an attack that take advantage of a system's vulnerabilities.

Easy

Build Finance DAO

The Build Finance DAO was a decentralized autonomous organization (DAO), a venture based on blockchain technology. It was the subject of a 2022 hostile takeover by a member who amassed enough votes to pass a motion that allowed them to liquidate the DAO's cryptocurrency holdings and flood the market with new tokens.

Bull

A person that is optimistic and confident that market prices will increase, this person is also known to be "bullish" about the market or price.

Easy

Bull Market

A bull market in crypto and stock markets refers to a time during which the prices of assets grow dramatically. These markets act as a source of motivation for both investors and purchasers. This is not a permanent state, although it can linger for months or even years.

Easy

Bull Run

A bull run (also known as a bull trend) is a period of time in the financial market during which the values of certain assets are constantly rising.

Easy

Bull Trap

A bull trap occurs when a steadily declining asset appears to reverse and go upward, but soon resumes its downward trend.

Easy

Bullish

Bullish is a Caymanian cryptocurrency exchange and blockchain technology company headquartered in George Town, Cayman Islands. The company provides infrastructure and services for the trading of digital assets through the Bullish Exchange platform, which is licensed in Germany, Hong Kong, Gibraltar, and New York State.

Bundle Africa

Bundle Africa, also known as Bundle, was a social payment software for user trading of cryptocurrencies, facilitating the sending and receiving of fiat, and user savings in dollars and other currencies.

Bundler

An ERC-4337 infrastructure node that collects UserOperations from the alternative mempool and submits them to the EntryPoint smart contract in a single on-chain transaction. Bundlers are compensated from the fees embedded in each UserOperation. They are distinct from validators and can be run permissionlessly by anyone.

Advanced

Bunz Trading Zone

Bunz Trading Zone is the name of a Canadian company and bartering marketplace application available on web, iOS, and Android.

Burn/Burned

Cryptocurrency tokens or coins are considered “burned” when they have been purposely and permanently removed from circulation.

Moderate

Bus encryption

Bus encryption is the use of encrypted program instructions on a data bus in a computer that includes a secure cryptoprocessor for executing the encrypted instructions. Bus encryption is used primarily in electronic systems that require high security, such as automated teller machines, TV set-top boxes, and secure data communication devices such as two-way digital radios.

Buy The (F*******) Dip (BTD/BTFD)

An enthusiastic exclamation by supporters of a cryptocurrency to buy while prices are at a low point.

A situation where communication that requires consensus on a single strategy from all members within a group or party cannot be trusted or verified.

Hard

Byzantium Fork

The Byzantium hard fork was geared towards making Ethereum's smart contracts suitable for usage in the commercial space and to increase the speed of the transactions with an enhancement in the security on its blockchain

Easy

C

C++

C++ is an extension of the C programming language that allows cross-platform developments and capabilities.

Moderate

Call Options

Call options are financial contracts that give an option buyer the right, but not the obligation, to purchase a stock, bond, commodity or other asset at a specific price.

Moderate

Canaan Creative

Canaan Inc., doing business as Canaan Creative and known simply as Canaan, is a Singapore-based computer hardware manufacturer. Established in 2013 by N.G. Zhang, Canaan specializes in Blockchain servers and ASIC microprocessors for use in bitcoin mining.

Candlesticks

A candlestick chart is a graphing technique used to show changes in price over time. Each candle provides 4 points of information opening price, closing price, high, and low. Also known as “candles” for short.

Easy

Canton Network

The Canton Network is a public blockchain network developed for financial institutions to enable secure, interoperable, and privacy‑preserving transactions. Launched in 2023 by a consortium of banks, exchanges, and technology firms including BNP Paribas, Capgemini, CBOE, Deloitte, Deutsche Börse, Digital Asset, Goldman Sachs, Microsoft, Moody's, and Paxos the network aims to connect disparate financial systems while meeting regulatory and privacy requirements.

Capital

Capital is most commonly defined as the large sum of money you would use to invest.

Easy

Capital Efficiencies

Capital efficiency is the ratio that compares the spending of a company on their growing revenue and how much they are receiving in return in the way of profits.

Easy

Capital Funds

Capital funding is the money provided in the form of debt or equity to operate a company.

Moderate

Capitulation

Capitulation is the process of selling assets or cryptocurrencies at a significant loss because you have lost hope or belief that it will ever increase in price.

Easy

Card Verifiable Certificate

Card Verifiable Certificates (CVC) are digital certificates that are designed to be processed by devices with limited computing power such as smart cards. This is achieved by using simple type–length–value (TLV) encoding with fixed fields. Fixed fields means that each field in the certificate is of fixed, or maximum, length and each field comes in a well defined order. This makes parsing easy, in contrast to asn.1 parsing which requires more processing and has to keep fields in memory while parsing nested content.

Cardano (blockchain platform)

Cardano is a public decentralized blockchain platform which uses the cryptocurrency, ADA, to facilitate transactions.

Casascius Coin

A physical unit of Bitcoin that comes in the form of brass, silver or gold-plated coins.

Moderate

Cascading Liquidations

Cascading liquidation refers to an event where liquidations pile on top of each other, resulting in a sudden price change.

Easy

Cash

Cash is the most liquid form of money: physical coins and banknotes in the most narrow sense of the term.

Easy

CashToken

CashTokens are a new set of opcodes that extend the capabilities of Bitcoin Cash to support new financial primitives in the form of fungible and non-fungible tokens.

Hard

Casper (Ethereum)

Casper is a project designed to implement PoS into the Ethereum network.

Hard

Cathie Wood

Cathie Wood is a top stock investor and the founder of ARK Invest, a $60 billion (assets) firm that invests in cutting-edge technologies, including self-driving vehicles and genomics.

Easy

CAVE-based authentication

CAVE-based authentication is a security protocol used to verify access in CDMA2000 1X, a type of third-generation (3G) mobile network system. The term "CAVE" stands for Cellular Authentication and Voice Encryption, which is the algorithm used to perform the authentication process. This system helps to confirm that a user is authorized to connect to the mobile network.

CCMP (cryptography)

Counter Mode Cipher Block Chaining Message Authentication Code Protocol or CCM mode Protocol (CCMP) is an authenticated encryption protocol designed for Wireless LAN products that implements the standards of the IEEE 802.11i amendment to the original IEEE 802.11 standard. CCMP is a data cryptographic encapsulation mechanism designed for data confidentiality, integrity and authentication. It is based upon the Counter Mode with CBC-MAC of the Advanced Encryption Standard (AES) standard. It was created to address the vulnerabilities presented by Wired Equivalent Privacy (WEP), a dated, insecure protocol.

CECPQ1

In cryptography, CECPQ1 is a post-quantum key-agreement protocol developed by Google as a limited experiment for use in Transport Layer Security (TLS) by web browsers. It was succeeded by CECPQ2.

CECPQ2

In cryptography, Combined Elliptic-Curve and Post-Quantum 2 (CECPQ2) is a quantum-secure modification to Transport Layer Security (TLS) 1.3 developed by Google. It is intended to be used experimentally, to help evaluate the performance of post-quantum key-exchange algorithms on actual users' devices.

CeDeFi

CeDeFi, or centralized decentralized finance, combines traditional centralized financial services with decentralized applications, merging conventional regulatory policies with modern financial products and infrastructure.

Moderate

In cryptography, a certificate authority or certification authority (CA) is an entity that stores, signs, and issues digital certificates. A digital certificate certifies the ownership of a public key by the named subject of the certificate. This allows others to rely upon signatures or on assertions made about the private key that corresponds to the certified public key. A CA acts as a trusted third party—trusted both by the subject (owner) of the certificate and by the party relying upon the certificate. The format of these certificates is specified by the X.509 or EMV standard.

Certificate Management over CMS

The Certificate Management over CMS (CMC) is an Internet Standard published by the IETF, defining transport mechanisms for the Cryptographic Message Syntax (CMS). It is defined in RFC 5272, its transport mechanisms in RFC 5273.

Certificate Management Protocol

The Certificate Management Protocol (CMP) is an Internet protocol standardized by the IETF used for obtaining X.509 public-key certificates in a PKI.

Certificate of Deposit (CD)

A certificate of deposit (CD) is a financial product allowing customers to earn an interest rate premium after making a deposit.

Moderate

Certificate revocation list

In cryptography, a certificate revocation list (CRL) is "a list of digital certificates that have been revoked by the issuing certificate authority (CA) before their scheduled expiration date and should no longer be trusted".

Certificate-based encryption

Certificate-based encryption is a system in which a certificate authority uses ID-based cryptography to produce a certificate. This system gives the users both implicit and explicit certification, the certificate can be used as a conventional certificate, but also implicitly for the purpose of encryption.

Certificateless cryptography

Certificateless cryptography is a variant of ID-based cryptography intended to prevent the key escrow problem. Ordinarily, keys are generated by a certificate authority or a key generation center (KGC) who is given complete power and is implicitly trusted. To prevent a complete breakdown of the system in the case of a compromised KGC, the key generation process is split between the KGC and the user. The KGC first generates a key pair, where the private key is now the partial private key of the system. The remainder of the key is a random value generated by the user, and is never revealed to anyone, not even the KGC. All cryptographic operations by the user are performed by using a complete private key which involves both the KGC's partial key, and the user's random secret value.

Certification path validation algorithm

The certification path validation algorithm is the algorithm which verifies that a given certificate path is valid under a given public key infrastructure (PKI). A path starts with the Subject certificate and proceeds through a number of intermediate certificates up to a trusted root certificate, typically issued by a trusted certificate authority (CA).

Certification Practice Statement

A Certification Practice Statement (CPS) is a document from a certificate authority or a member of a web of trust which describes their practice for issuing and managing public key certificates.

Chaffing and winnowing

Chaffing and winnowing is a cryptographic technique to achieve confidentiality without using encryption when sending data over an insecure channel. The name is derived from agriculture: after grain has been harvested and threshed, it remains mixed together with inedible fibrous chaff. The chaff and grain are then separated by winnowing, and the chaff is discarded. The cryptographic technique was conceived by Ron Rivest and published in an on-line article on 18 March 1998. Although it bears similarities to both traditional encryption and steganography, it cannot be classified under either category.

Chain of trust

In computer security, a chain of trust is established by validating each component of hardware and software from the end entity up to the root certificate. It is intended to ensure that only trusted software and hardware can be used while still retaining flexibility.

Chain Reorganization

An event where the network switches from one chain tip to a longer competing chain, orphaning one or more recently mined blocks and their transactions. Transactions in orphaned blocks return to the mempool and must be re-mined. Exchanges and merchant services typically wait for several confirmations before treating a deposit as final, precisely to survive shallow reorganizations.

Advanced

Chain Split

Chain splits are another term used to describe cryptocurrency forks — the separation of a single original coin into several independently managed projects.

Easy

Chainlink (blockchain oracle)

Chainlink is a decentralized blockchain oracle network. Chainlink's token is on Ethereum. The network is intended to be used to facilitate the transfer of tamper-proof data from off-chain sources to on-chain smart contracts.

Change

Change — a concept relevant to cryptocurrencies that use the UTXO model — is the number of coins sent back to a user after they use their unspent outputs to initiate a transaction.

Moderate

Change Address

In cryptocurrencies, a change address is where the change from a transaction is temporarily stored before it is returned to the sender wallet.

Moderate

Changpeng Zhao (CZ)

Changpeng Zhao (CZ) is the founder of crypto exchange Binance.

Easy

Chaos Communication Congress

The Chaos Communication Congress is an annual hacker conference organized by the Chaos Computer Club. The congress features a variety of lectures and workshops on technical and political issues related to security, cryptography, privacy and online freedom of speech. It has taken place regularly at the end of the year since 1984, with the current date and duration established in 2005. It is considered one of the largest events of its kind, alongside DEF CON in Las Vegas.

Chaotic cryptology

Chaotic cryptology is the application of mathematical chaos theory to the practice of cryptography, the study or techniques used to privately and securely transmit information with the presence of a third-party or adversary. Since first being investigated by Robert Matthews in 1989, the use of chaos in cryptography has attracted much interest. However, long-standing concerns about its security and implementation speed continue to limit its implementation.

Chargeback

A chargeback is the return of money to the payer of a certain transaction, most commonly one that was made with a credit or debit card.

Easy

Chicago Mercantile Exchange (CME)

The Chicago Mercantile Exchange (CME) is one of the largest exchanges dealing in the trading of futures and options in the United States.

Easy

Chiliz

Chiliz is a blockchain platform developed by Maltese-based sports company Mediarex. The Chiliz blockchain powers the Socios.com platform, which offers "fan tokens" to users, enabling them to participate in polls hosted by the clubs, or receive rewards and promotions. The native token Chiliz is used to buy the fan tokens. Alexandre Dreyfus is the CEO of Chiliz and Beatrice Collet is the managing director.

China RealDID

China Real-Name Decentralized Identifier System is China's national-level decentralized identifier system. China RealDID was officially launched on December 12, 2023, by the First Research Institute of China's Ministry of Public Security and the Blockchain-based Service Network (BSN) China.

Client certificate

In cryptography, a client certificate is a type of digital certificate that is used by client systems to set up a secure connection to a remote server. Certificates contain information about the client and are signed by a certificate authority. Client certificates can provide mutual authentication without the use of passwords.

Client-side encryption

Client-side encryption is the cryptographic technique of encrypting data on the sender's side, before it is transmitted to a server such as a cloud storage service. Client-side encryption features an encryption key that is not available to the service provider, making it difficult or impossible for service providers to decrypt hosted data. Client-side encryption allows for the creation of applications whose providers cannot access the data its users have stored, thus offering a high level of privacy.

Clipboard Hijack

A malware technique that monitors the system clipboard and silently replaces a copied wallet address with an attacker-controlled address before you paste it into a send field. Because crypto addresses are long and opaque, most users do not notice the substitution. Always verify the first and last characters of a pasted address against the original source, or use QR codes instead of copy-paste.

Moderate

Close

Refers to the closing price; similar to the same term used in stock trading.

Easy

Cloud

Cloud servers are typically located throughout different data centers all over the world.

Easy

Cloud Mining

Cryptocurrency mining with remote processing power rented from companies.

Moderate

CNGN

cNGN is a Nigerian stablecoin pegged 1:1 to the Nigerian Naira (₦).

Co-Signer

A person or entity that has partial control and access over a cryptocurrency wallet.

Moderate

Co-Signing

The act of a second party adding their cryptographic signature to a transaction that has already been signed by the first party. In SSP's 2-of-2 model, co-signing is the final step: SSP Key receives the partially signed transaction from SSP Wallet (via the relay), validates the details, and applies the second signature before broadcast. Neither party can unilaterally complete the transaction.

Beginner

Cobden Centre

The Cobden Centre is a British economics think tank founded by Member of Parliament Steve Baker and entrepreneur Toby Baxendale. It was developed by and consists of proponents of the Austrian School of Economics. Contributors include MP Steve Baker, Professor Kevin Dowd, Gordon Kerr of Cobden Partners, MEP Dr Syed Kamall, former Cambridge University lecturer Jamie Whyte, former UKIP MP Douglas Carswell, Ivo Mosley and Keith Weiner. The editor is Max Rangeley.

Code

The action of coding is to write programming statements for a program.

Easy

Code (cryptography)

In cryptology, a code is a method used to encrypt a message that operates at the level of meaning; that is, words or phrases are converted into something else. A code might transform "change" into "CVGDK" or "cocktail lounge". The U.S. National Security Agency defined a code as "A substitution cryptosystem in which the plaintext elements are primarily words, phrases, or sentences, and the code equivalents typically consist of letters or digits in otherwise meaningless combinations of identical length." A codebook is needed to encrypt, and decrypt the phrases or words.

Code Access Security

Code Access Security (CAS), in the Microsoft .NET framework, is Microsoft's solution to prevent untrusted code from performing privileged actions. When the CLR loads an assembly it will obtain evidence for the assembly and use this to identify the code group that the assembly belongs to. A code group contains a permission set. Code that performs a privileged action will perform a code access demand which will cause the CLR to walk up the call stack and examine the permission set granted to the assembly of each method in the call stack. The code groups and permission sets are determined by the administrator of the machine who defines the security policy. Microsoft considers CAS as obsolete and discourages its use. It is also not available in .NET Core and .NET.

Code Repository

A code repository is a digital library where developers store and collaborate on their codes with ease, like a code-specific Google Drive or Dropbox.

Easy

Code word (communication)

In communication, a code word is an element of a standardized code or protocol. Each code word is assembled in accordance with the specific rules of the code and assigned a unique meaning. Code words are typically used for reasons of reliability, clarity, brevity, or secrecy.

Codebook

A codebook is a type of document used for gathering and storing cryptography codes. Originally, codebooks were often literally books, but today "codebook" is a byword for the complete record of a series of codes, regardless of physical format.

Codress message

In military cryptography, a codress message is an encrypted message whose address is also encrypted. This is usually done to prevent traffic analysis.

The first transaction in a new block is a coinbase transaction in which the miner receives Bitcoins and mining fees.

Moderate

CoinEx

CoinEx is a global cryptocurrency exchange founded in 2017 by blockchain mining pool ViaBTC. It lists cryptocurrencies for trading and issues the CoinEx Token (CET), used on the platform for fee discounts, staking, and governance.

CoinJar

CoinJar is a centralised digital currency exchange with the main function to facilitate the trading of cryptocurrencies by its users and allow to convert these assets into cash. It is one of the earliest cryptocurrency exchanges to launch in Australia.

CoinRemitter

CoinRemitter is a Singaporean cryptocurrency payment service provider. It was founded in 2017 and enables merchants to accept payments in various cryptocurrencies.

Coinsquare

Coinsquare is a Canadian cryptocurrency exchange company regulated by the Investment Industry Regulatory Organization of Canada.

In cryptography, a collision attack on a cryptographic hash tries to find two inputs producing the same hash value, i.e. a hash collision. This is in contrast to a preimage attack where a specific target hash value is specified.

Colored Coins

Colored Coins is an open-source protocol that allows users to represent and manipulate immutable digital resources on top of Bitcoin transactions. They are a class of methods for representing and maintaining real-world assets on the Bitcoin blockchain, which may be used to establish asset ownership. Colored coins are bitcoins with a mark on them that specifies what they may be used for. Colored coins have also been considered a precursor to NFTs.

Commingling

Commingling of funds is a method of combining all funds from different investors into a single investment in order to maximize the benefits.

Easy

Commitment scheme

A commitment scheme is a cryptographic primitive that allows one to commit to a chosen value while keeping it hidden to others, with the ability to reveal the committed value later. Commitment schemes are designed so that a party cannot change the value or statement after they have committed to it: that is, commitment schemes are binding. Commitment schemes have important applications in a number of cryptographic protocols including secure coin flipping, zero-knowledge proofs, and secure computation.

Commodity Futures Trading Commission (CFTC)

The Commodity Futures Trading Commission (CFTC) is an independent federal regulatory agency responsible for regulation the U.S. derivatives market.

Easy

Communications security

Communications security is the discipline of preventing unauthorized interceptors from accessing telecommunications in an intelligible form, while still delivering content to the intended recipients.

Community Development Council Vouchers Scheme

The Community Development Council Vouchers Scheme, known colloquially as CDC Vouchers, is a social transfer and economic stimulus program in Singapore, administered by the five Community Development Councils (CDCs) under the purview of the People's Association (PA) and the Ministry of Culture, Community and Youth (MCCY). First introduced in 2020 as a targeted relief measure for lower-income households during the COVID-19 pandemic, the scheme has since evolved into a universal, digitalised fiscal transfer program. It is now distributed on a recurring basis to all Singaporean households, regardless of income level or housing type.

Community Takeover (CTO)

Originally developed in 2019 by Microsoft under the name Coco and later rebranded to Confidential Consortium Framework (CCF), it is an open-source framework for developing of a new category of performant applications that focuses on the optimization of secure multi-party computation and data availability. Intended to accelerate the adoption of blockchain technology by enterprises, CCF can enable a variety of high-scale, confidential, permissioned distributed ledger networks that meet key enterprise requirements.

Confirmation

In cryptocurrency, a confirmation is a measure of how many blocks have actually passed since a transaction was added to a blockchain.

Easy

Confirmation Depth

The number of blocks mined on top of the block containing a given transaction. A transaction mined in the most recent block has a depth of 1 (one confirmation); a depth of 6 is the traditional threshold for treating a Bitcoin payment as irreversible. Deeper confirmation depth makes a double-spend attack exponentially more expensive for a miner.

Beginner

Confirmations

A cryptocurrency transaction is considered confirmed when it is included in a block on the blockchain. Each new block after the first one is an additional confirmation for that transaction.

Moderate

Conjugate coding

Conjugate coding is a cryptographic tool, introduced by Stephen Wiesner in the late 1960s. It is part of the two applications Wiesner described for quantum coding, along with a method for creating fraud-proof banking notes. The application that the concept was based on was a method of transmitting multiple messages in such a way that reading one destroys the others. This is called quantum multiplexing and it uses photons polarized in conjugate bases as "qubits" to pass information. Conjugate coding also is a simple extension of a random number generator.

Consensus

Consensus is achieved when all participants of the network agree on the order and content of the blocks in the blockchain.

Moderate

Consensus Layer

The consensus layer is the backbone of any blockchain network, performing the vital role of facilitating agreement among nodes on the true state of the blockchain.

Easy

Consensus Mechanism

A consensus mechanism is an underlying technology behind the main functionalities of all blockchain technology, which makes them an essential operating feature of all cryptocurrencies.

Hard

ConsenSys

ConsenSys is a blockchain technology company that offers developer tools alongside enterprise solutions.

Easy

Consolidation

Consolidation in trading is when a crypto asset trades between two levels, and the market shows indecisiveness about the next move.

Moderate

Consortium Blockchain

A privately owned and operated blockchain where a consortium shares information not readily available to the public, while relying on the immutable and transparent properties of the blockchain.

Moderate

ConstitutionDAO

ConstitutionDAO was a decentralized autonomous organization (DAO) formed in November 2021 to purchase an original copy of the United States Constitution. The group raised $47 million in Ether cryptocurrency, but lost to a bid of $43.2 million in the Sotheby's auction. The organization was disbanded later that month.

Consumer Price Index (CPI)

A Consumer Price Index (or CPI) is a type of index where the prices of a basket of goods and services are tracked to gain insights into market segments

Easy

Content Credentials

Content Credentials are a digital media metadata specification. They aim to provide provenance information about a piece of media and help prove its authenticity. They are described as the equivalent of nutrition labels for digital media. One of the stated goal of this specification is to fight online disinformation.

Contract

In traditional finance, a contract is a binding agreement between two parties. In cryptocurrencies, smart contracts execute functions on the blockchain.

Easy

Contract Account

A contract account is an account that has a crypto balance and associated code.

Moderate

Contract for Difference (CFD)

A contract for difference (CFD) outlines a buyer’s obligation to pay any price difference that might occur due to the shifting valuation of an asset.

Moderate

Contract Wallet

A smart contract deployed on-chain that controls funds according to programmatic rules, rather than a single private key. Contract wallets can enforce multisig quorums, spending limits, time locks, and social recovery. Safe Multisig is the most widely used contract wallet on Ethereum; ERC-4337 generalizes this pattern to make contract wallets first-class transaction senders.

Moderate

Convergent encryption

Convergent encryption, also known as content hash keying, is a cryptosystem that produces identical ciphertext from identical plaintext files. This has applications in cloud computing to remove duplicate files from storage without the provider having access to the encryption keys. The combination of deduplication and convergent encryption was described in a backup system patent filed by Stac Electronics in 1995. This combination has been used by Farsite, Permabit, Freenet, MojoNation, GNUnet, flud, and the Tahoe Least-Authority File Store.

Coordinator

In blockchain technology, a coordinator is a specialized client that allows nodes to verify the validity of their copy of the ledger against specific transactions.

Moderate

Core Wallet

A core crypto wallet is able to contain the entire blockchain, rather than just a piece of a blockchain.

Moderate

Corporate Treasury

A corporate treasury is formed to manage and control the liquidity, risk, funds, capital reserves, and other resources of a company to align with its short and long-term strategies.

Easy

Correction

A correction is a pullback of an asset’s price of at least 10% to adjust for over-valuation.

Moderate

Correlation immunity

In mathematics, the correlation immunity of a Boolean function is a measure of the degree to which its outputs are uncorrelated with some subset of its inputs. Specifically, a Boolean function is said to be correlation-immune of order m if every subset of m or fewer variables in is statistically independent of the value of .

Cosigner

Any party that holds one of the keys in a multisig quorum and is authorized to contribute a signature toward spending. In SSP's 2-of-2 setup, both the SSP Wallet device and the SSP Key device are cosigners; every spend requires both. In larger M-of-N arrangements, cosigners may be separate individuals, hardware devices, or automated services.

Beginner

Cosmos (network)

Cosmos is a blockchain ledger software platform designed to enable the creation of application-specific, distributed ledgers that can communicate and transfer data across each other. The project is supported by the Interchain Foundation, a Swiss foundation registered in Zug, Switzerland, established in 2017 to fund open-source blockchain development, and developed by its subsidiary Cosmos Labs.

Counter-Terrorism Financing

Counter-terrorism financing refers to efforts to disrupt and cut off the money supply used to fund terrorist organizations and activities.

Moderate

Counterparty (platform)

Counterparty is a DeFi platform and Internet protocol built on top of the Bitcoin blockchain. It was one of the most well-known "Bitcoin 2.0" platforms in 2014.

Cover (telecommunications)

In telecommunications and tradecraft, cover is the technique of concealing or altering the characteristics of communications patterns for the purpose of denying an unauthorized receiver information that would be of value.

Cover-coding

Cover-coding is a technique for obscuring the data that is transmitted over an insecure link, to reduce the risks of snooping. An example of cover-coding would be for the sender to perform a bitwise XOR of the original data with a password or random number which is known to both sender and receiver. The resulting cover-coded data is then transmitted from sender to the receiver, who uncovers the original data by performing a further bitwise XOR operation on the received data using the same password or random number.

CPU Miner

Since mining requires computing power, the process of generating or mining cryptocurrency using a central processing unit (CPU) is called CPU mining (or central processing unit mining).

Easy

Craig Wright

Craig Wright is an Australian computer scientist associated with Bitcoin SV.

Easy

Credit Rating

Credit rating is a measure that allows banks and lending institutions to predict how capable you are of repaying your debt.

Easy

Credit Risk

Crest risk is the number representing the possibility that a bank or lending institution will lose money because a borrower cannot repay their loan.

Easy

Critical security parameter

In cryptography, a critical security parameter (CSP) is information that is either user or system defined and is used to operate a cryptography module in processing encryption functions including cryptographic keys and authentication data, such as passwords, the disclosure or modification of which can compromise the security of a cryptographic module or the security of the information protected by the module.

Cross Margin

Cross Margin, also known as "Spread Margin" is a margin method that utilizes the full amount of funds in the available balance to avoid liquidations. Any realized profit & loss statement (P&L) from other positions can aid in adding margin on a losing position.

Hard

Cross-Border Trading

Cross-border trading in financial markets and trade finance represents the opportunity to trade globally using a local currency.

Moderate

Cross-Chain

Cross-chain is a technology that enhances the interconnection between blockchain networks by allowing the exchange of information and value.

Moderate

Cross-Chain Communication

Cross-chain communication between blockchains allows different protocols to verify data and transactions without the intervention of a centralized third-party service.

Moderate

Cross-chain Contract Calls

Cross-chain contract calls allow information, cryptocurrencies or NFTs, which would otherwise be constrained to their own network, to move freely between blockchains via smart contracts.

Hard

Crowdfunding

The crypto-trading hamster, also known as Mr. Goxx, was a hamster that selected cryptocurrencies to buy or sell on a trading platform. The hamster used his hamster wheel to "choose" cryptocurrencies, and two tunnels marked "Buy" and "Sell" were electronically wired to complete trades when he ran through them. Mr. Goxx died on 26 November 2021.

Crypto: The Game

Crypto: The Game is a browser-based interactive survival game that combines blockchain mechanics with multiplayer elimination challenges.

Crypto.com

Crypto.com is a cryptocurrency exchange company based in Singapore that offers various financial services, including an app, exchange, and noncustodial DeFi wallet, NFT marketplace, and direct payment service in cryptocurrency. As of June 2023, the company reportedly had 100 million customers and 4,000 employees.

Cryptoasset

A cryptoasset is any digital asset that uses cryptographic technologies to maintain its operation as a currency or decentralized application.

Easy

Cryptochannel

In telecommunications, a cryptochannel is a complete system of crypto-communications between two or more holders or parties. It includes: (a) the cryptographic aids prescribed; (b) the holders thereof; (c) the indicators or other means of identification; (d) the area or areas in which effective; (e) the special purpose, if any, for which provided; and (f) pertinent notes as to distribution, usage, etc. A cryptochannel is analogous to a radio circuit.

Cryptocurrencies in Europe

The general notion of cryptocurrencies in Europe denotes the processes of legislative regulation, distribution, circulation, and storage of hcryptocurrencies in Europe. In April 2023, the EU Parliament passed the Markets in Crypto Act (MiCA) unified legal framework for crypto-assets within the European Union.

Cryptocurrencies in Puerto Rico

With the arrival of several figures led by Brock Pierce following the passing of hurricane Maria in 2017, cryptocurrency became an issue of media and economic interest in the Caribbean archipelago of Puerto Rico. These traders relocated to the island motivated by the tax incentives provided by Act 20-2012 and Act 22-2012 and the tropical setting. They claimed that their intention was to create an utopian blockchain "crypto city" or "community", which at various times became known by the names of Puertopia, Crypto Rico, Puerto Crypto or Sol, calling themselves Puertopians. The ideas promoted by this group have prompted a mixed reception, being favored by gubernatorial administrations but also spawning protests from political and grassroots movements that raise concerns about disaster capitalism, gentrification and settler colonialism. Puerto Rico has earned a reputation as a hub for cryptocurrency enthusiasts and, according to Pierce, by 2021 the archipelago had the largest quantity of coins concentrated in a single place in the world.

Cryptocurrency

Cryptocurrencies are digital currencies that use cryptographic technologies to secure their operation.

Easy

Cryptocurrency and crime

Cryptocurrency and crime describes how criminals use cryptocurrencies or target them for criminal purposes. This includes investment and romance scams, ransomware payments, thefts and exchange hacks, money laundering and sanctions evasion, darknet-market transactions, and off-chain coercion to obtain private keys. Law enforcement notes that investment fraud and laundering are frequent criminal uses of cryptocurrencies, while noting that public blockchains can also aid law inforcement in tracing, seizures, and arrests.

Cryptocurrency bubble

A cryptocurrency bubble is a phenomenon where the market increasingly considers the going price of cryptocurrency assets to be inflated against their hypothetical value. The history of cryptocurrency has been marked by several speculative bubbles on a boom to bust cycle.

Cryptocurrency exchange

A cryptocurrency exchange, or a digital currency exchange (DCE), is a business that allows customers to trade cryptocurrencies or digital currencies for other assets, such as conventional fiat money or other digital currencies. Exchanges may accept credit card payments, wire transfers or other forms of payment in exchange for digital currencies or cryptocurrencies. A cryptocurrency exchange can be a market maker that typically takes the bid–ask spreads as a transaction commission for its service or, as a matching platform, simply charges fees.

Cryptocurrency in Iran

Cryptocurrency in Iran has emerged as a pivotal response to economic pressures and global isolation. In 2026, Iran had a total US$7.8 billion cryptocurrency market, and a number of exchanges such as Nobitex. Iran's interest in cryptocurrencies began in 2017 when international sanctions obstructed Iran's access to the global financial markets. In 2019, the government legalized cryptocurrency mining under specific conditions. The country's cryptocurrency market has since faced challenges like high energy costs and the Islamic Revolutionary Guard Corps using cryptocurrency in illicit activities.

Cryptocurrency Money Laundering

Cryptocurrency money laundering is a method criminals use to legitimize and enshroud funds by changing fiat to digital currency and then routing it through many pathways. It is an attempt to lose any authorities who may be tracing the money.

Easy

Cryptocurrency Pairs

Exchanges utilize cryptocurrency pairs in order to facilitate the trade between different tokens.

Easy

Cryptocurrency tracing

Cryptocurrency tracing is a digital forensic technique used to track and analyze the flow of cryptocurrencies across blockchain networks. Law enforcement agencies, regulators, and cybersecurity experts use cryptocurrency tracing to identify and combat fraud.

Cryptocurrency wallet

A cryptocurrency wallet is a device, physical medium, program or an online service which stores the public and/or private keys for cryptocurrency transactions. In addition to this basic function of storing the keys, a cryptocurrency wallet more often offers the functionality of encrypting and/or signing information. Signing can for example result in executing a smart contract, a cryptocurrency transaction, identification, or legally signing a 'document'.

Cryptoeconomics

Cryptoeconomics is an evolving economic paradigm for a cross-disciplinary approach to the study of digital economies and decentralized finance (DeFi) applications. Cryptoeconomics integrates concepts and principles from traditional economics, cryptography, computer science, and game theory disciplines. Just as traditional economics provides a theoretical foundation for traditional financial services, cryptoeconomics provides a theoretical foundation for DeFi services bought and sold via fiat cryptocurrencies, and executed by smart contracts.

Cryptographic bill of materials

Cryptographic bill of materials is a structured inventory of all cryptographic assets present in a software, firmware, device, or system. It enumerates algorithms, cryptographic libraries or modules, digital certificates, keys and related material, and protocols in use, and maps their relationships to the components that implement or invoke them. CBOMs are used to improve security analysis, compliance, and cryptographic agility, and are increasingly referenced in guidance for post‑quantum cryptography (PQC) migration.

Cryptographic Hash Function

Cryptographic hash functions produce a fixed-size hash value from a variable-size transaction input.

Moderate

Cryptographic High Value Product

Cryptographic High Value Product (CHVP) is a designation used within the information security community to identify assets that have high value, and which may be used to encrypt / decrypt secure communications, but which do not retain or store any classified information. When disconnected from the secure communication network, the CHVP equipment may be handled with a lower level of controls than required for COMSEC equipment.

Cryptographic Message Syntax

The Cryptographic Message Syntax (CMS) is the IETF's standard for cryptographically protected messages. It can be used by cryptographic schemes and protocols to digitally sign, digest, authenticate or encrypt any form of digital data.

Cryptographic module

A cryptographic module is a component of a computer system that securely implements cryptographic algorithms, typically with some element of tamper resistance.

Cryptographic Module Testing Laboratory

Cryptographic Module Testing Laboratory (CMTL) is an information technology (IT) computer security testing laboratory that is accredited to conduct cryptographic module evaluations for conformance to the FIPS 140-2 U.S. Government standard.

Cryptographic multilinear map

A cryptographic -multilinear map is a kind of multilinear map, that is, a function such that for any integers and elements , , and which in addition is efficiently computable and satisfies some security properties. It has several applications on cryptography, as key exchange protocols, identity-based encryption, and broadcast encryption. There exist constructions of cryptographic 2-multilinear maps, known as bilinear maps, however, the problem of constructing such multilinear maps for seems much more difficult and the security of the proposed candidates is still unclear.

Cryptographic nonce

In cryptography, a nonce is an arbitrary number that can be used just once in a cryptographic communication. It is often a random or pseudo-random number issued in an authentication protocol to ensure that each communication session is unique, and therefore that old communications cannot be reused in replay attacks. Nonces can also be useful as initialization vectors and in cryptographic hash functions.

Cryptographic primitive

Cryptographic primitives are well-established, low-level cryptographic algorithms that are frequently used to build cryptographic protocols for computer security systems. These routines include, but are not limited to, one-way hash functions and encryption functions.

Cryptographic protocol

A cryptographic protocol is an abstract or concrete protocol that performs a security-related function and applies cryptographic methods, often as sequences of cryptographic primitives. A protocol describes how the algorithms should be used and includes details about data structures and representations, at which point it can be used to implement multiple, interoperable versions of a program.

Cryptographic Service Provider

A cryptographic service provider (CSP) is a package that "provides a concrete implementation of certain cryptographic services."

Cryptographically Generated Address

A Cryptographically Generated Address (CGA) is an Internet Protocol Version 6 (IPv6) address that has a host identifier computed from a cryptographic hash function. This procedure is a method for binding a public signature key to an IPv6 address in the Secure Neighbor Discovery Protocol (SEND).

Cryptographically secure pseudorandom number generator

A cryptographically secure pseudorandom number generator (CSPRNG) or cryptographic pseudorandom number generator (CPRNG) is a pseudorandom number generator (PRNG) with properties that make it suitable for use in cryptography. It is also referred to as a cryptographic random number generator (CRNG).

Cryptography

A field of study and practice to secure information, preventing third parties from reading information to which they are not privy.

Easy

Cryptojacking

Cryptojacking is the act of exploiting a computer to mine cryptocurrencies, often through websites, against the user's will or while the user is unaware. One notable piece of software used for cryptojacking was Coinhive, which was used in over two-thirds of cryptojacks before its March 2019 shutdown. The cryptocurrencies mined the most often are privacy coins—coins with hidden transaction histories—such as Monero and Zcash.

Cryptojacking

The use of another party’s computer to mine cryptocurrency without their consent.

Moderate

CryptoKitties

CryptoKitties is a blockchain game developed by Canadian studio Dapper Labs. The game allows players to buy, sell, and create non-fungible tokens (NFTs) using Ethereum. These NFTs represent virtual cats. The game's popularity in December 2017 congested the Ethereum network, causing it to reach an all-time high in the number of transactions and slowing it down significantly.

Cryptology

Cryptology is the scientific study of cryptography as well as cryptanalysis.

Easy

CryptoNote

CryptoNote is an application layer protocol designed for use with cryptocurrencies that aims to solve specific problems identified in Bitcoin.

CryptoParty

CryptoParty (Crypto-Party) is a grassroots global endeavour to introduce the basics of practical cryptography such as the Tor anonymity network, I2P, Freenet, key signing parties, disk encryption and virtual private networks to the general public. The project primarily consists of a series of free public workshops.

Cryptopia

Cryptopia was an international cryptocurrency exchange based in Christchurch, New Zealand. Founded in 2014 by Rob Dawson and Adam Clark, it was among the earliest cryptocurrency services started in the country, and was responsible for launching the first stablecoin pegged to the New Zealand dollar. Cryptopia experienced substantial growth in 2017 from 30,000 users to over 1.4 million by 2018. At its peak in late 2010s, Cryptopia was one of the top 100 cryptocurrency exchanges by trading volume, reportedly outpacing that of the New Zealand Stock Exchange, and went on to operate in 900 currencies.

CryptoPunks

A collection of Ethereum-based non-fungible tokens.

Moderate

Cryptosystem

In cryptography, a cryptosystem is a suite of cryptographic algorithms needed to implement a particular security service, such as confidentiality (encryption).

Cryptovirology

Cryptovirology refers to the study of cryptography use in malware, such as ransomware and asymmetric backdoors. Traditionally, cryptography and its applications are defensive in nature, and provide privacy, authentication, and security to users. Cryptovirology employs a twist on cryptography, showing that it can also be used offensively. It can be used to mount extortion based attacks that cause loss of access to information, loss of confidentiality, and information leakage, tasks which cryptography typically prevents.

CrySyS Lab

CrySyS Lab is part of the Department of Telecommunications at the Budapest University of Technology and Economics. The name is derived from "Laboratory of Cryptography and System Security", the full Hungarian name is CrySys Adat- és Rendszerbiztonság Laboratórium.

Cypherpunks: Freedom and the Future of the Internet is a 2012 book by Julian Assange, in discussion with Internet activists and cypherpunks Jacob Appelbaum, Andy Müller-Maguhn and Jérémie Zimmermann. Its primary topic is society's relationship with information security. In the book, the authors warn that the Internet has become a tool of the police state, and that the world is inadvertently heading toward a form of totalitarianism. They promote the use of cryptography to protect against state surveillance.

D

Daedalus Wallet

Daedalus Wallet is a multi-platform, open-source, hierarchical-deterministic wallet that lets you generate an endless number of keys from a single seed.

Hard

Dai (cryptocurrency)

DAI is a stablecoin token on the Ethereum blockchain which uses smart contracts designed to control supply to keep its value as close to one United States dollar as possible. DAI is maintained and regulated by MakerDAO, a decentralized autonomous organization composed of the owners of its governance token, MKR, who may propose and vote on changes to certain parameters in its smart contracts.

DAO Summoning

DAO summoning is the act of creating or forming a DAO. The term is typically used in the context of forming a new Moloch DAO, though it can also refer to the formation of any new DAO.

Easy

Dark Web

A portion of the internet existing on darknets not indexed by search engines, that can only be accessed with specific software, configurations or authorizations.

Easy

Darknodes

RenVM is driven by Darknodes, a decentralized network of computers. In exchange for compensation, they offer their computing power and storage space to everyone with certain conditions.

Hard

Dash (cryptocurrency)

Dash is an open source cryptocurrency. It is an altcoin that was forked from the Bitcoin protocol. It is also a decentralized autonomous organization (DAO) run by a subset of its users. It was previously known as Xcoin and Darkcoin.

Data Availability Sampling (DAS)

Data Availability Sampling (DAS) is a method that enables decentralized applications to verify the availability of block data without requiring the entire dataset to be downloaded by each participant.

Hard

Data Privacy

Data privacy refers to the area of data protection and security that is responsible for the handling of sensitive data.

Easy

Data Scraping

Data scraping or web scraping is the process of extracting information from a website into a spreadsheet or a local file on your computer or database.

Easy

Data Validation

Data validation is the process of clarifying the accuracy, integrity and quality of a set of data before it is used.

Easy

Database encryption

Database encryption can generally be defined as a process that uses an algorithm to transform data stored in a database into "cipher text" that is incomprehensible without first being decrypted. It can therefore be said that the purpose of database encryption is to protect the data stored in a database from being accessed by individuals with potentially "malicious" intentions. The act of encrypting a database also reduces the incentive for individuals to hack the aforementioned database as "meaningless" encrypted data adds extra steps for hackers to retrieve the data. There are multiple techniques and technologies available for database encryption, the most important of which will be detailed in this article.

Decentraland is a 3D virtual world platform. Users may buy virtual plots of land in the platform as NFTs via the MANA cryptocurrency, which uses the Ethereum blockchain. Designers can create and sell clothes and accessories for the avatars to be used in the virtual world.

Decentralization Maximalism

Decentralization maximalism refers to the belief that decentralization is the best approach and lifestyle to such a degree that any form of regulation does not need to exist.

Easy

Decentralization Ratio

The Decentralization Ratio (DR) is the ratio of collateral value that is decentralized over the total stablecoin supply backed for those assets.

Moderate

Decentralized

Decentralization refers to the property of a system in which nodes or actors work in concert in a distributed fashion to achieve a common goal.

Easy

Decentralized API (dAPI)

API services that are intrinsically interoperable with blockchain technology are known as decentralized application programming interfaces (dAPIs). This is an invention of the API3 protocol.

Easy

Decentralized application

A decentralised application is an application that can operate autonomously, typically through the use of smart contracts, that run on a blockchain or other distributed ledger system. DApps provide some function or utility to its users with less human intervention. Control over DApps is distributed to holders of tokens that represent ownership. Without any one entity controlling the system, the application is therefore decentralised.

Decentralized Applications (DApps)

A type of application that runs on a decentralized network, avoiding a single point of failure.

Moderate

Decentralized Autonomous Initial Coin Offerings (DAICO)

A method for decentralized funding of projects that introduces a form of governance in the ICO process, allowing backers to vote for the return of their funds if certain conditions are met.

Moderate

Hard

Decipherment

In philology and linguistics, decipherment is the discovery of the meaning of the symbols found in extinct languages and/or alphabets. Decipherment is possible with respect to languages and scripts. One can also study or try to decipher how spoken languages that no longer exist were once pronounced, or how living languages used to be pronounced in prior eras.

Decryption

The process of transforming encrypted data back into a format that is readable by a user or machine.

Moderate

Deep Web

The "deep web" is the part of the internet that is hidden from regular search engines.

Easy

Delegated credential is a short-lived TLS certificate used to improve security by faster recovery from private key leakage, without increasing the latency of the TLS handshake. It is currently an IETF Internet Draft, and has been in use by Cloudflare and Facebook, with browser support by Firefox.

Delegated Path Discovery

Delegated Path Discovery (DPD) is a method for querying a trusted server for information about a public key certificate.

Delegated Path Validation

Delegated Path Validation (DPV) is a cryptographic method used to offload the task of validating the certification path of digital certificates from the client to a trusted server. This process is integral to various security protocols that rely on Public Key Infrastructure (PKI). DPV aim to enhance the efficiency of certification path validation by leveraging a server dedicated to this task, which provides validation results to the client. This approach is particularly useful in resource-constrained environments where clients may not have the computational power to perform extensive certificate validation themselves.

Delegated Proof-of-Stake (dPOS)

An alternative to the Proof-of-Stake and Proof-of-Work consensus algorithms.

Moderate

Delisting

The process of removing an asset/stock/cryptocurrency from a trading exchange is called delisting.

Easy

Demurrage

Demurrage is a fee charged for using an asset beyond a certain time period.

Moderate

Dencun Upgrade

Dencun is essentially the fusion of two separate upgrades - 'Deneb' and ‘Cancun’ together targeting improvements across Ethereum's consensus and execution layers.

Moderate

Deniable authentication

In cryptography, deniable authentication is message authentication between a set of participants where the participants themselves can be confident in the authenticity of the messages, but it cannot be proved to a third party after the event.

DEX aggregators are a relatively new type of blockchain-based service that allow cryptocurrency traders to benefit from a large variety of financial tools in a single interface, often providing better liquidity and prices on different crypto pairs.

Hard

Dharma Protocol

An open-source stack for building debt markets on Ethereum.

Moderate

Diamond Hands

Diamond Hands is a popular term on social media platforms. It refers to people who hold their coins even if their portfolio drops in value by more than 20%.

Easy

Diem (digital currency)

Diem was a permissioned blockchain-based stablecoin payment system proposed by the American social media company Facebook. The plan also included a private currency implemented as a cryptocurrency. The launch was originally planned to be in 2020, but only rudimentary experimental code was released.

Difficulty

A measure of how hard it is to validate a new block on a blockchain.

Easy

Diffie–Hellman key exchange

Diffie–Hellman (DH) key exchange is a mathematical method of securely generating a symmetric cryptographic key over a public channel and was one of the first protocols as conceived by Ralph Merkle and named after Whitfield Diffie and Martin Hellman. DH is one of the earliest practical examples of public key exchange implemented within the field of cryptography. Published in 1976 by Diffie and Hellman, this is the earliest publicly known work that proposed the idea of a private key and a corresponding public key.

Digest access authentication

Digest access authentication is one of the agreed-upon methods a web server can use to negotiate credentials, such as username or password, with a user's web browser. This can be used to confirm the identity of a user before sending sensitive information, such as online banking transaction history. It applies a hash function to the username and password before sending them over the network. In contrast, basic access authentication uses the easily reversible Base64 encoding instead of hashing, making it non-secure unless used in conjunction with TLS.

DigiCipher 2

DigiCipher 2, or simply DCII, is a proprietary standard format of digital signal transmission and it doubles as an encryption standard with MPEG-2/MPEG-4 signal video compression used on many communications satellite television and audio signals. The DCII standard was originally developed in 1997 by General Instrument, which then became the Home and Network Mobility division of Motorola, then bought by Google in Aug 2011, and lastly became the Home portion of the division to Arris.

Digital credentials are the digital equivalent of paper-based credentials. Just as a paper-based credential could be a passport, a driver's license, a membership certificate or some kind of ticket to obtain some service, such as a cinema ticket or a public transport ticket, a digital credential is a proof of qualification, competence, or clearance that is attached to a person. Also, digital credentials prove something about their owner. Both types of credentials may contain personal information such as the person's name, birthplace, birthdate, and/or biometric information such as a picture or a finger print.

Digital Currency

A currency that exists only in digital form, as opposed to traditional physical currencies.

Easy

Digital Currency Group

Digital Currency Group Inc. (DCG) is an American investment company focusing on the digital currency market and decentralized technologies. It is located in Stamford, Connecticut. The company currently has the subsidiaries Grayscale Investments, Yuma, Foundry, Luno, and Fortitude Mining. It also formerly owned the now-inactive Genesis Global Holdco and CoinDesk.

Digital data

Digital data or digital information, in information theory and information systems, is data or information represented as a string of discrete symbols, each of which can take on one of only a finite number of values from some alphabet, such as letters or digits. An example is a text document, which consists of a string of alphanumeric characters. The most common form of digital data in modern information systems is binary data, which is represented by a string of binary digits (bits) each of which can have one of two values, either 0 or 1.

Digital Dollar

The term "digital dollar" refers to a possible digital currency issued by the US central bank (CBDC).

Easy

Digital Identity

Information used by a person or entity to identify themselves to a computer or network.

Easy

Digital Initial Private Offering

Digital Initial Private Offering (DIPO) is a trademarked capital-raising model developed by LiveTrade LTD, a Delaware-based financial technology company established in 2019. The model is designed to help small and medium-sized enterprises (SMEs) raise capital through the tokenization of their securities using blockchain technology.

Digital Signature

A method for proving the authenticity of a digital communication.

Moderate

Digital Signature Algorithm

The Digital Signature Algorithm (DSA) is a public-key cryptosystem and Federal Information Processing Standard for digital signatures, based on the mathematical concept of modular exponentiation and the discrete logarithm problem. In a digital signature system, there is a keypair involved, consisting of a private and a public key. In this system a signing entity that declared their public key can generate a signature using their private key, and a verifier can assert the source if it verifies the signature correctly using the declared public key. DSA is a variant of the Schnorr and ElGamal signature schemes.

Digital Signature Algorithm (DSA)

Digital Signature Algorithm (DSA) is a signature algorithm, not an encryption algorithm, and uses public-key cryptography to generate digital signatures.

Easy

Digital ticket

A digital ticket is a virtual instance of a ticket which represents the digitization of rights to claim goods or services.

Digital wallet

A digital wallet, also known as an e-wallet or mobile wallet, is an electronic device, online service, or software program that allows one party to make electronic transactions with another party bartering digital currency units for goods and services. This can include purchasing items either online or at the point of sale in a brick and mortar store, using either mobile payment or using a laptop or other personal computer. Money can be deposited in the digital wallet prior to any transactions or, in other cases, an individual's bank account can be linked to the digital wallet. Users might also have their driver's license, health card, loyalty card(s) and other ID documents stored within the wallet. The credentials can be passed to a merchant's terminal wirelessly via near field communication (NFC).

Dildo

No, not that. The red or green “candles,” or vertical lines, on graphs showing cryptocurrency market data.

Moderate

Dining cryptographers problem

In cryptography, the dining cryptographers problem studies how to perform a secure multi-party computation of the boolean-XOR function. David Chaum first proposed this problem in the early 1980s and used it as an illustrative example to show that it was possible to send anonymous messages with unconditional sender and recipient untraceability. Anonymous communication networks based on this problem are often referred to as DC-nets.

Dip

A dip is when markets experience a short or protracted downturn.

Easy

Direct Anonymous Attestation

Direct Anonymous Attestation (DAA) is a cryptographic primitive which enables remote authentication of a trusted computer whilst preserving privacy of the platform's user. The protocol has been adopted by the Trusted Computing Group (TCG) in the latest version of its Trusted Platform Module (TPM) specification to address privacy concerns. ISO/IEC 20008 specifies DAA, as well, and Intel's Enhanced Privacy ID (EPID) 2.0 implementation for microprocessors is available for licensing RAND-Z along with an open source SDK.

Directed Acyclic Graph (DAG)

A way of structuring data, often used for data modelling, and increasingly as a consensus tool in cryptocurrencies.

Hard

Discord

Discord is a web-based communication tool or application primarily built to enable communication between gamers.

Easy

Discrete logarithm

In mathematics, for given real numbers and , the logarithm is a number such that . The discrete logarithm generalizes this concept to a cyclic group. A simple example is the group of integers modulo a prime number under modular multiplication of nonzero elements.

Discriminant Book

The Discriminant Book shortened to K-Book (K. Buch), and also known as the indicator group book or identification group book was a secret distribution list in booklet form, which listed trigraphs in random order. The Kenngruppenbuch was introduced in May 1937, and used by the Kriegsmarine during World War II as part of the Naval Enigma message encipherment procedure, to ensure secret and confidential communication between Karl Dönitz, Commander of Submarines (BdU) in the Atlantic and in the Mediterranean operating German submarines. The Kenngruppenbuch was used in the generation of the Enigma message Key that was transmitted within the message Indicator. The Kenngruppenbuch was used from 5 October 1941, for the Enigma Model M3, and from 1 February 1942 exclusively for the Enigma M4. It must not be confused with the Kenngruppenheft which was used with the Short Signal Book.

Distance-bounding protocol

Distance bounding protocols are cryptographic protocols that enable a verifier V to establish an upper bound on the physical distance to a prover P.

Distributed Consensus

Collective agreement reached among nodes in a network.

Moderate

Distributed Denial of Service (DDoS) Attack

An attempt by a bad actor to disrupt the operation of an application, server or network by flooding it with traffic.

Moderate

Distributed key generation

Distributed key generation (DKG) is a cryptographic process in which multiple parties contribute to the calculation of a shared public and private key set. Unlike most public key encryption models, distributed key generation does not rely on Trusted Third Parties. Instead, the participation of a threshold of honest parties determines whether a key pair can be computed successfully. Distributed key generation prevents single parties from having access to a private key. The involvement of many parties requires Distributed key generation to ensure secrecy in the presence of malicious contributions to the key calculation.

Distributed Ledger

Distributed ledgers are ledgers in which data is stored across a network of decentralized nodes. A distributed ledger does not necessarily involve a cryptocurrency and may be permissioned and private.

Moderate

Distributed Ledger Technology (DLT)

A database that is shared by multiple participants, in multiple places. The basis for blockchains.

Moderate

Distributed Network

A network in which the data and applications are dependent on multiple sources, as opposed to one location.

Moderate

Distributed point function

In cryptography, a distributed point function is a cryptographic primitive that allows two distributed processes to share a piece of information, and compute functions of their shared information, without revealing the information itself to either process. It is a form of secret sharing.

Distributed System Security Architecture

Distributed System Security Architecture or (DSSA) is a computer security architecture that provides a suite of functions including login, authentication, and access control in a distributed system. To differ from other similar architectures, the DSSA architecture offers the ability to access all these functions without the trusted server being active.

Distributed Validator Technology (DVT)

DVT operates as a security system for staking validators. It spreads key management and signs tasks across multiple parties.

Hard

Distribution Phase

The distribution phase is the opposite of the accumulation phase. In this phase, the market moves sideways and is range-bound after experiencing an extended uptrend.

Moderate

Diversification

Diversification is a risk-management strategy that mixes a wide variety of investments within a portfolio.

The Domain Name System Security Extensions (DNSSEC) is a suite of extension specifications by the Internet Engineering Task Force (IETF) for securing data exchanged in the Domain Name System (DNS) in Internet Protocol (IP) networks. The protocol provides cryptographic authentication of data, authenticated denial of existence, and data integrity, but not availability or confidentiality. As of 2025, DNSSEC deployment is spotty.

Domain separation

In cryptography, domain separation is a construct used to implement multiple different functions using only one underlying template in an efficient way. The domain separation can be defined as partitioning of the domain of a function to assign separate subdomains to different applications of the same function.

DRC-20 is a token standard on the Dogecoin network that allows developers and users to create fungible assets within Dogecoin's ecosystem. It is similar to ERC-20 on Ethereum.

Hard

Drecom

Drecom Co., Ltd. is a Japanese software, web, video game development and video game publishing company. Subsidiaries Drecom Media and DRE Novels publish light novels.

Drivechain

Drivechain is a Bitcoin improvement proposal that aims to scale Bitcoin and add new features using sidechains.

Moderate

DWF Labs is a private company involved in trading, market making, and investing in cryptocurrency, based in Dubai.

DYCO (Dynamic Coin Offering)

DYCO (dynamic coin offering) is a new crowdfunding model developed by DAO Maker that employs utility tokens that are backed by USD.

Moderate

DYOR

The acronym of Do Your Own Research — encouraging investors to complete due diligence into a project before investing.

Easy

E

E-Dirham

e-Dirham is a digital payment service offering mobile wallets in the United Arab Emirates. It was launched by the United Arab Emirates government in 2001 to streamline the collection of service fees. Initially developed for federal use, it has since expanded to local governments and private entities.

E-Money Directive

The E-Money Directive or the electronic money directive regulates electronic payment systems in the European Union. The aim is to enable new and secure electronic money services and to foster effective competition between all market participants.

E-Signature

An electronic signature, or e-signature, is any electronic mark (sign, sound, symbol, etc.) used in place of a physical signature in signing a document or contract.

Moderate

Eagle Cash

EagleCash and its sister programs EZpay and Navy Cash are cash management applications that use stored-value card technology to process financial transactions in "closed-loop" operating environments. The United States Department of the Treasury sponsors the programs for the United States Armed Forces. The Federal Reserve Bank of Boston administers the programs for the Treasury, and they are in use at approved U.S. military facilities inside and outside the continental United States. The systems use a plastic payment card, similar to a credit or debit card, which has an embedded microchip that tracks the card's balance and interfaces with encrypted card readers. This method allows soldiers to purchase goods and services at U.S. military posts and canteens, without carrying cash, or manage their personal bank accounts while on deployment or in training. The program reduces the amount of American currency required overseas, reduces theft, saves thousands of man-hours in labor, helps reduce the risk of transporting cash in combat environments, and increases security and convenience for service members. It helped reduce or eliminate the need for cash and money orders.

ECache

eCache was a digital gold currency (DBC) provider which operated over the Tor network from 2007 to 2014.

Ecash

Ecash was conceived by David Chaum as an anonymous cryptographic electronic money or electronic cash system in 1982. It was realized through his corporation Digicash and used as micropayment system at one US bank from 1995 to 1998.

ECDSA

Elliptic Curve Digital Signature Algorithm — the signature scheme used by Bitcoin and pre-Taproot Ethereum. A private key produces a variable-length DER-encoded (r, s) signature (typically 71–72 bytes on Bitcoin) over a message hash; anyone with the corresponding public key can verify it without learning the private key. Bitcoin's secp256k1 curve is used for ECDSA; Ethereum uses the same curve but with an additional recovery parameter.

Moderate

Economic Utility

Economic utility is a term in economics that refers to the total satisfaction that a person can derive from consuming a good or service.

Easy

Economics of bitcoin

Bitcoin was designed by its pseudonymous inventor, Satoshi Nakamoto, to work as a currency, but its status as a currency is disputed. Economists define money as a store of value, a medium of exchange and a unit of account, and agree that bitcoin does not currently meet all these criteria.

Economy of Second Life

The online video game Second Life has its own economy and a virtual token referred to as Linden Dollars (L$). In the SL economy, users buy from and sell to one another directly, using the Linden, which is a closed-loop virtual token for use only within the Second Life platform. Linden Dollars have no monetary value and are not redeemable for monetary value from Linden Lab. However, the presence of a currency exchange has led to the Linden Dollar being recognised as a centralized virtual currency, a fiat currency, or property. A resident with a surplus of Linden Dollars earned via a Second Life business or experiential play can offer to exchange with other users via the LindeX exchange provided by Linden Lab. This economy is independent of the price of the game, which users pay to Linden Lab, not to each other. Linden Lab reported that the Second Life economy generated US$3,596,674 in economic activity during the month of September 2005, and in September 2006, Second Life was reported to have a GDP of US$64,000,000.

EdDSA

In public-key cryptography, Edwards-curve Digital Signature Algorithm (EdDSA) is a digital signature scheme using a variant of Schnorr signature based on twisted Edwards curves. It is designed to be faster than existing digital signature schemes without sacrificing security. It was developed by a team including Daniel J. Bernstein, Niels Duif, Tanja Lange, Peter Schwabe, and Bo-Yin Yang. The reference implementation is public-domain software.

Edge Nodes

In computer science, an edge node is a computer that serves as an end-user gateway to form a connection with other nodes.

Hard

EDX Markets

EDX Markets is an institutional cryptocurrency exchange. Backed by several prominent financial firms—including Citadel Securities, Virtu Financial, Fidelity Digital Assets, Charles Schwab Corporation, Sequoia Capital, HRT Technology and Miami International Holdings—EDX Markets offers trading, settlement and clearing services globally.

Effective Proof-of-Stake

Effective Proof-of-Stake is Harmony’s version of the Proof-of-Stake consensus mechanism that aims for both security and decentralization.

Moderate

EIP-1559

EIP-1559 is an upgrade to the Ethereum network that simplified the fee market mechanism.

Hard

EIP-712

An Ethereum standard for structured data signing that produces human-readable signature requests in wallet UIs instead of opaque hex blobs. EIP-712 encodes the domain, type, and data fields so users can see exactly what they are signing — a token permit, a trade order, or a multisig payload. It is the foundation for gasless approvals and off-chain order books.

Moderate

El Zonte

El Zonte is a town in La Libertad Department in El Salvador. A popular tourist destination, El Zonte has been described as a "world surfing mecca". Playa El Zonte became one of the first locales in El Salvador to accept bitcoin as a payment method, and inspired the country's adoption of bitcoin as a legal tender.

Election security

Election cybersecurity or election security refers to the protection of elections and voting infrastructure from cyberattack or cyber threat – including the tampering with or infiltration of voting machines and equipment, election office networks and practices, and voter registration databases.

Electronic Money Association

The Electronic Money Association (EMA) is the trade body representing electronic money issuers in Europe.

Electronic Money Institution

An Electronic Money Institution (EMI) is a financial institution that is authorised to issue electronic money and provide payment services such as domestic and international electronic funds transfers and can provide bank accounts and e-wallets. EMIs are similar to banks except they are not allowed to lend money.

Electronic signature

An electronic signature, or e-signature, is data that is logically associated with other data and which is used by the signatory to sign the associated data. This type of signature has the same legal standing as a handwritten signature as long as it adheres to the requirements of the specific regulation under which it was created.

Electrum (software)

Electrum is a free non-custodial cryptocurrency wallet for Bitcoin and Lightning Network. It is available for Windows, Linux, macOS and Android. Electrum is written in Python and uses the Qt widget toolkit for the user interface. Electrum is a lightweight client: it does not download the entire blockchain and instead uses simplified payment verification. Transactions are sent to public servers. It was released in 2011.

Electrum Wallet

A Bitcoin wallet for Windows, macOS and Linux with a simple interface.

Easy

ELI5

Short for “explain like I’m five” — a plea for simplicity when crypto concepts are being explained.

Easy

Elliott Waves

The Elliott Wave Theory is an essential tool for many stock and crypto market traders.

Easy

Elliptic (company)

Elliptic is a British blockchain analytics firm headquartered in London, with offices in New York and Singapore. The company was co-founded by Adam Joyce, Tom Robinson and James Smith in 2013. It is the first company to develop cryptoasset anti-money laundering and sanctions compliance tools based on blockchain analytics. Its clients are primarily financial institutions and crypto businesses, although it also provides blockchain investigation tools and data to government agencies. Customers have included cryptocurrency exchanges, banks, and government agencies.

Elliptic Curve

A mathematical structure defined by an equation of the form y² = x³ + ax + b over a finite field, used in public-key cryptography because discrete logarithms on the curve are computationally hard. Bitcoin and Ethereum both use the secp256k1 curve; a 256-bit private key maps to a unique public key, but deriving the private key from the public key is infeasible with current hardware.

Advanced

Elliptic Curve Digital Signature Algorithm

In cryptography, the Elliptic Curve Digital Signature Algorithm (ECDSA) offers a variant of the Digital Signature Algorithm (DSA) which uses elliptic-curve cryptography.

Elliptic curve only hash

The elliptic curve only hash (ECOH) algorithm was submitted as a candidate for SHA-3 in the NIST hash function competition. However, it was rejected in the beginning of the competition since a second pre-image attack was found.

Elliptic-curve cryptography

Elliptic-curve cryptography (ECC) is an approach to public-key cryptography based on the algebraic structure of elliptic curves over finite fields. ECC allows smaller keys to provide equivalent security, compared to cryptosystems based on modular exponentiation in finite fields, such as the RSA cryptosystem and ElGamal cryptosystem.

EMA (Exponential Moving Average)

Exponential moving average (EMA) is a technical indicator that highlights the recent price changes and data points of an asset/stock/cryptocurrency while keeping the older chart observations intact.

Easy

Email Spoofing

Email spoofing is a technique that is used in order to trick users into thinking that a message actually came from a different person.

Easy

Emission

The speed at which new coins are produced and released.

Moderate

Encrypted function

An encrypted function is an attempt to provide mobile code privacy without providing any tamper-resistant hardware. It is a method where in mobile code can carry out cryptographic primitives.

Encrypted key exchange

Encrypted Key Exchange is a family of password-authenticated key agreement methods described by Steven M. Bellovin and Michael Merritt. Although several of the forms of EKE in this paper were later found to be flawed, the surviving, refined, and enhanced forms of EKE effectively make this the first method to amplify a shared password into a shared key, where the shared key may subsequently be used to provide a zero-knowledge password proof or other functions.

Encryption

Encryption is a method through which information can be made into code.

Moderate

End-to-end encryption

End-to-end encryption (E2EE) is a method of implementing a secure communication system where only the sender and intended recipient can read the messages. No one else, including the system provider, telecom providers, Internet providers or malicious actors, can access the cryptographic keys needed to read or send messages.

Enhanced privacy ID

Enhanced privacy ID (EPID) is Intel Corporation's recommended algorithm for attestation of a trusted system while preserving privacy. It has been incorporated in several Intel chipsets since 2008 and Intel processors since 2011. At RSAC 2016 Intel disclosed that it has shipped over 2.4B EPID keys since 2008. EPID complies with international standards ISO/IEC 20008 / 20009, and the Trusted Computing Group (TCG) TPM 2.0 for authentication. Intel contributed EPID intellectual property to ISO/IEC under RAND-Z terms. Intel is recommending that EPID become the standard across the industry for use in authentication of devices in the Internet of Things (IoT) and in December 2014 announced that it was licensing the technology to third-party chip makers to broadly enable its use.

Enrollment over Secure Transport

The Enrollment over Secure Transport, or EST is a cryptographic protocol that describes an X.509 certificate management protocol targeting public key infrastructure (PKI) clients that need to acquire client certificates and associated certificate authority (CA) certificates. EST is described in RFC 7030. EST has been put forward as a replacement for SCEP, being easier to implement on devices already having an HTTPS stack. EST uses HTTPS as transport and leverages TLS for many of its security attributes. EST has described standardized URLs and uses the well-known Uniform Resource Identifiers (URIs) definition codified in RFC 5785.

Enterprise Blockchain

Enterprise blockchain is the use of distributed ledger technology for non-speculative business purposes. Tailored for the needs of enterprises, these chains may be private or public.

Hard

Enterprise Ethereum Alliance (EEA)

A group of organizations and companies working together to further develop the Ethereum network.

Moderate

Entropic security

Entropic security is a security definition used in the field of cryptography. Modern encryption schemes are generally required to protect communications even when the attacker has substantial information about the messages being encrypted. For example, even if an attacker knows that an intercepted ciphertext encrypts either the message "Attack" or the message "Retreat", a semantically secure encryption scheme will prevent the attacker from learning which of the two messages is encrypted. However, definitions such as semantic security are too strong to achieve with certain specialized encryption schemes. Entropic security is a weaker definition that can be used in the special case where an attacker has very little information about the messages being encrypted.

Entropy

A measure of randomness used as the raw seed material when generating cryptographic keys. BIP-39 wallets require 128 or 256 bits of high-quality entropy to generate a 12- or 24-word mnemonic. Weak entropy — from a predictable source like a date of birth or a poorly seeded RNG — makes private keys susceptible to brute-force generation by an attacker.

Moderate

Environmental impact of bitcoin

The environmental impact of bitcoin has been characterized in the literature as significant, particularly due to its energy use, greenhouse gas emissions, and electronic waste. Bitcoin mining, the process by which bitcoins are created and transactions are finalized, is energy-consuming and results in carbon emissions, as 48% of the electricity used in 2025 was generated through fossil fuels while 52% was generated through sustainable energy sources. Moreover, bitcoins are mined on specialized computer hardware resulting in electronic waste. Scholars argue that bitcoin mining could support renewable energy development by utilizing surplus electricity from wind and solar. As of 2025, several empirical studies report an association between higher bitcoin-mining electricity use and worse environmental-sustainability indicators. Bitcoin's environmental impact has attracted the attention of regulators, leading to incentives or restrictions in various jurisdictions.

EOA

Externally Owned Account — an Ethereum account controlled by a private key rather than contract code. EOAs can initiate transactions directly and pay gas; smart contracts cannot initiate transactions on their own. Most Ethereum wallets are EOAs, but account abstraction (ERC-4337) allows contract wallets to behave like EOAs through a bundler and EntryPoint.

Moderate

EOS.IO

EOS.IO is a blockchain protocol based on the cryptocurrency EOS. The smart contract platform claims to eliminate transaction fees and also conduct millions of transactions per second. It was developed by the private company Block.one and launched in 2017. The platform was later released as open-source software.

Epoch

One entire run of the training dataset through the algorithm is referred to as an epoch in machine learning.

Easy

Aadhaar eSign is an online electronic signature service in India to facilitate an Aadhaar holder to digitally sign a document. The signature service is facilitated by authenticating the Aadhaar holder via the Aadhaar-based e-KYC service.

Esports

Electronic sports, commonly known as e-sports, is a term used for digital gaming competition, in which players battle against each other in an individual or team-based format often in a competition or event that offers huge monetary rewards to the winners. Some e-sports games are also available in a single-player mode.

Easy

Estcoin

Estcoin was a 2017 proposal for a national cryptocurrency tied to Estonia's e-residency program. The plan was criticized by the European Central Bank President Mario Draghi, who said "no member state can introduce its own currency". In 2018, the Estonian government clarified it was not planning to launch a national cryptocurrency and that it never planned to do so, but would plan to "explore various possibilities" for blockchain technology.

ETH/BTC

ETH/BTC is a popular cryptocurrency trading pair that denominates the price of Ethereum in Bitcoin.

Easy

Ethash

Ethash is the algorithm utilized for the proof of work mining Ethereum and ETH-based cryptocurrencies.

Hard

Ether

The form of payment used in the operation of the distribution application platform, Ethereum.

Easy

Ethereum

Ethereum is a decentralized blockchain with smart contract functionality. Ether is the native cryptocurrency of the platform. Among cryptocurrencies, ether is second only to bitcoin in market capitalization. It is open-source software.

Ethereum Classic

Ethereum Classic is a blockchain-based distributed computing platform that offers smart contract (scripting) functionality. Ethereum Classic was created in a hard fork with the mainline Ethereum blockchain, and maintains the original, unaltered ledger prior to the attempt to reverse a hacking attack on the Ethereum-based DAO in July 2016. It is now the largest smart contract platform secured by a proof-of-work consensus mechanism, following Ethereum's transition to proof-of-stake in 2022. It is open source and supports a modified version of Nakamoto consensus via transaction-based state transitions executed on a public Ethereum Virtual Machine (EVM).

Ethereum Difficulty

Ethereum difficulty plays a crucial role in maintaining the stability and security of the network, especially in the context of Ethereum's transition to a Proof-of-Stake (PoS) consensus mechanism.

Easy

Ethereum ETF

An Ethereum Exchange Traded Fund (ETF) is an investment tool that allows investors to get exposed to Ethereum's price movements through traditional stock exchanges.

Moderate

Ethereum Improvement Proposal (EIP)

Ethereum Improvement Proposals (EIPs) describe standards for the Ethereum platform, including core protocol specifications, client APIs, and contract standards.

Hard

Ethereum Request For Comment (ERC)

Ethereum Request for Comment (ERC) is the protocol to introduce new improvements to the network by developers.

Moderate

Ethereum Transaction

Ethereum transaction are cryptographically signed instructions to initiate a transaction to update the state of the Ethereum network.

Easy

Ethereum Virtual Machine (EVM)

A Turing-complete virtual machine that enables execution of code exactly as intended; it is the runtime environment for every smart contract. Every Ethereum node runs on the EVM to maintain consensus across the blockchain.

Hard

EtherRock

EtherRock is a collection of 100 non-fungible token (NFT) on the Ethereum blockchain, created in December 2017. Each token depicts a stylized, differently colored rock image.

EToro

eToro Group Ltd. is an Israeli multi-asset investment and social trading company focused on providing financial services. eToro was founded in 2007 in Tel Aviv by Yoni Assia, Ronen Assia, and David Ring. The company's headquarters are located in Central Israel, with global offices in Cyprus, United Kingdom, United States, Australia, Germany and UAE. At the beginning of 2025, the company filed for Nasdaq (U.S.) listing and went public on 14 May. In May 2025, eToro had 40 million registered users, and over 3.63 million funded accounts. In 2025, the company valuation was $5.64 billion.

Event Triggers

When a transaction is mined, smart contracts can emit events and write logs to the blockchain which the frontend can then process.

Hard

Everydays: the First 5000 Days

Everydays: the First 5000 Days is a digital work of art created by Mike Winkelmann, known professionally as Beeple. The work is a collage of 5000 digital images created by Winkelmann for his Everydays series. Its associated non-fungible token (NFT) was sold for $69.3 million at Christie's in 2021, making it the most expensive NFT ever.

Exchange

Businesses that allow customers to trade cryptocurrencies for fiat money or other cryptocurrencies.

Easy

Exchange Traded Fund (ETF)

A security that tracks a basket of assets such as stocks, bonds, and cryptocurrencies but can be traded like a single stock.

Moderate

Exit Scam

An exit scam is a trick where projects disappear (or shut down) after accumulating investors’ money. In other industries, this event occurs when a business stops shipping orders even if it is receiving payment for the new ones.

Easy

Exodus Wallet

Exodus is a cryptocurrency wallet available on desktop and mobile platforms. It was founded in 2015 by JP Richardson and Daniel Castagnoli. Exodus wallet supports digital assets including Bitcoin, Ethereum, and Solana. It is available on Windows, macOS, Linux, iOS, Android, and as a browser extension.

Extended Public Key

An xpub (or ypub/zpub for SegWit variants) is a BIP-32 node that lets any party derive all child public keys in a subtree without knowing any private key. SSP Wallet and SSP Key each share their xpub with each other during pairing to construct the multisig descriptor; neither device can sign on behalf of the other, but both can generate receive addresses.

Advanced

F

Facebook Credits

Facebook Credits was a virtual currency that enabled people to purchase items in games and non-gaming applications on the Facebook Platform. One U.S. dollar was the equivalent of 10 Facebook Credits. Facebook Credits were available in 15 currencies including U.S. dollars, pound sterling, euros, and Danish kroner. Facebook was hoping eventually to expand Credits into a micropayment system open to any Facebook application, whether a game or a media company application. Facebook deprecated Credits in favour of users' local currencies.

In cryptography, the fast syndrome-based hash functions (FSB) are a family of cryptographic hash functions introduced in 2003 by Daniel Augot, Matthieu Finiasz, and Nicolas Sendrier. Unlike most other cryptographic hash functions in use today, FSB can to a certain extent be proven to be secure. More exactly, it can be proven that breaking FSB is at least as difficult as solving a certain NP-complete problem known as regular syndrome decoding so FSB is provably secure. Though it is not known whether NP-complete problems are solvable in polynomial time, it is often assumed that they are not.

FATF Travel Rule

The FATF Travel Rule requires virtual asset service providers to regulate information sharing for certain large transactions.

Easy

Faucet

A cryptocurrency reward system usually on a website or app, that rewards users for completing certain tasks.

Easy

Fee Tiers

Fee tiers refer to the fee structure that determines the amount charged when investors deposit or withdraw money and execute trades on a crypto exchange.

Easy

Feistel cipher

In cryptography, a Feistel cipher is a symmetric structure used in the construction of block ciphers, named after the German-born physicist and cryptographer Horst Feistel, who did pioneering research while working for IBM; it is also commonly known as a Feistel network. A large number of block ciphers use the scheme, including the US Data Encryption Standard, the Soviet/Russian GOST and the more recent Blowfish and Twofish ciphers. In a Feistel cipher, encryption and decryption are very similar operations, and both consist of iteratively running a function called a "round function" a fixed number of times.

Fiat

Fiat currency is “legal tender” backed by a central government, such as the Federal Reserve, with its own banking system, such as fractional reserve banking. It can take the form of physical cash, or it can be represented electronically, such as with bank credit.

Easy

Fiat On-Ramp

A fiat-on ramp is a way to get cryptocurrency from fiat, or regular money.

Easy

Fiat-Pegged Cryptocurrency

A coin, token or asset issued on a blockchain that is linked to a government or bank-issued currency.

Moderate

Fibonacci Retracement Level

A signed software update applied to the operating system of a hardware wallet or embedded device. Firmware updates can patch security vulnerabilities, add coin support, and improve the signing UI. Before applying a firmware update to a hardware wallet, always back up your seed phrase — some updates reset the device. SSP distributes app updates through standard app stores rather than device firmware.

Beginner

Firo (cryptocurrency)

Firo, formerly known as Zcoin, is a cryptocurrency aimed at using cryptography to provide better privacy for its users compared to other cryptocurrencies such as Bitcoin.

First In, First Out

First in, First Out (FIFO) is an inventory method used to specify your cost-basis when calculating your taxes.

Moderate

Fork (Software)

When an entirely new program has been developed from source code, taken from an open source software.

Moderate

Fork Choice Rule

The fork choice rule is a mechanism in Ethereum that allows nodes to agree on a canonical chain when the network splits into competing forks.

Moderate

FORK-256

FORK-256 is a hash algorithm designed in response to security issues discovered in the earlier SHA-1 and MD5 algorithms. After substantial cryptanalysis, the algorithm is considered broken.

Forking lemma

The forking lemma is any of a number of related lemmas in cryptography research. The lemma states that if an adversary, on inputs drawn from some distribution, produces an output that has some property with non-negligible probability, then with non-negligible probability, if the adversary is re-run on new inputs but with the same random tape, its second output will also have the property.

Form 1099-DA

Form 1099-DA is an Internal Revenue Service (IRS) tax form used to report the sale or exchange of digital assets, such as cryptocurrency, stablecoins, and non-fungible tokens (NFTs). Introduced for the 2025 tax year, it represents the first standardized information return specifically dedicated to digital asset transactions, bringing reporting requirements for digital brokers in line with those of traditional financial institutions.

Format-preserving encryption

In cryptography, format-preserving encryption (FPE), refers to encrypting in such a way that the output is in the same format as the input. The meaning of "format" varies. Typically only finite sets of characters are used; numeric, alphabetic or alphanumeric. For example:Encrypting a 16-digit credit card number so that the ciphertext is another 16-digit number. Encrypting an English word so that the ciphertext is another English word. Encrypting an n-bit number so that the ciphertext is another n-bit number.

Format-transforming encryption

In cryptography, format-transforming encryption (FTE) refers to encryption where the format of the input plaintext and output ciphertext are configurable. Descriptions of formats can vary, but are typically compact set descriptors, such as a regular expression.

Forward anonymity

Forward anonymity is a property of a cryptographic system which prevents an attacker who has recorded past encrypted communications from discovering its contents and participants in the future. This property is analogous to forward secrecy.

Forward secrecy

In cryptography, forward secrecy (FS), also known as perfect forward secrecy (PFS), is a feature of specific key-agreement protocols that gives assurances that session keys will not be compromised even if long-term secrets used in the session key exchange are compromised, limiting damage. For TLS, the long-term secret is typically the private key of the server. Forward secrecy protects past sessions against future compromises of keys or passwords. By generating a unique session key for every session a user initiates, the compromise of a single session key will not affect any data other than that exchanged in the specific session protected by that particular key. This by itself is not sufficient for forward secrecy, which additionally requires that a long-term secret compromise does not affect the security of past session keys.

Fractional Stablecoins

A fractional stablecoin is one that is backed in two ways: collaterally-backed and algorithmically modified.

Moderate

Fraud Proof

A fraud proof is a technological method that functions as a bond in a decentralized environment that uses Optimistic Rollups (ORs), which are sidechains that aim to reduce the costs and latency that dApps might encounter on a blockchain platform.

Hard

Front Running

Front running is when you place a transaction in a queue when you have knowledge of a future transaction.

Moderate

FROST

Flexible Round-Optimized Schnorr Threshold signatures — a protocol that allows a group of N parties to collaboratively produce a single Schnorr signature, with any threshold T of them present. Unlike ECDSA-based threshold schemes, FROST signatures are indistinguishable from single-signer Schnorr signatures on-chain, providing privacy and fee savings. FROST is a candidate for future SSP key schemes on Taproot-enabled chains.

Advanced

Functional encryption (FE) is a generalization of public-key encryption in which possessing a secret key allows one to learn a function of what the ciphertext is encrypting.

Fundamental Analysis (FA)

Fundamental analysis is a method of evaluating the underlying economic and financial factors that affect the value of an asset.

Easy

Funding Payments

Funding payments are periodic payments between traders. These are designed to reduce the discrepancy between the perpetual market price and the spot market price.

Hard

Fungible

In cryptocurrency, fungibility is when a coin or token can be replaced by any other identical coin or token.

Easy

Fusion Rollups

Fusion rollups are a blockchain scalability solution that combines the best of other L2 approaches such as Appchains and Shared Rollups.

Hard

Futo

Futo is an organization that develops and invests in decentralized technologies and companies.

Moderate

Futures

A futures contract is a standardized legal agreement to buy or sell a particular commodity or asset at a predetermined price at a specified time in the future.

Easy

G

Gains

Gains refer to an increase in value or profit.

Easy

Game Channels

Game channels are the newest technological advancement in the world of blockchain gaming, as they enable fast gameplay by removing the wait time for block confirmations. With game channels, games and dApps can run off-chain securely, individually, and in near real-time.

Easy

Game Theory

Game theory is a way of creating a simplified interactive environment (a ‘game’) that allows researchers to model how people and entities will respond to certain actions.

Easy

GameFi

GameFi, better known as play-to-earn (P2E) games, is a rather new term in the field of both gaming and cryptocurrency industries. It references games that are designed with economic and financial aspects of blockchain and cryptocurrencies, enabling players to exert full control over their in-game assets to generate revenue.

Easy

Garantex

Garantex was a Russian cryptocurrency exchange that was co-founded in 2019 by Stanislav Drugalev, Sergey Mendeleev and Aleksandr Mira Serda, located in the Federation Tower. It is mainly known for exchanging rubles for other currencies via trading them through cryptocurrencies, avoiding sanctions based on the 2022 Russian invasion of Ukraine.

Gold-backed digital token, abbreviated as GBDT is an investment instrument used in Zimbabwe. It was formerly known as ZiG, but its name was taken by a newly created gold backed currency, the Zimbabwean ZiG, thus renaming this investment instrument to GBDT. The digital coins are not loanable.

Gemini (cryptocurrency exchange)

Gemini Space Station Inc. (Gemini) is an American cryptocurrency exchange and custodian bank. It was founded in 2014 by Cameron and Tyler Winklevoss.

Gems

Gem is a term for relatively unknown low-cap coins that have immense potential or are grossly undervalued.

Easy

Generic Bootstrapping Architecture

Generic Bootstrapping Architecture (GBA) is a technology that enables the authentication of a user. This authentication is possible if the user owns a valid identity on an HLR or on an HSS.

Generic Security Service Algorithm for Secret Key Transaction

GSS-TSIG is an extension to the TSIG DNS authentication protocol for secure key exchange. It is a GSS-API algorithm which uses Kerberos for passing security tokens to provide authentication, integrity and confidentiality.

Genesis (cryptocurrency company)

Genesis is a cryptocurrency intermediary for institutional investors, with Digital Currency Group (DCG) as its parent company.

Genesis Block

The first block of data that is processed and validated to form a new blockchain, often referred to as block 0 or block 1.

Easy

GENIUS Act

The Guiding and Establishing National Innovation for U.S. Stablecoins Act is a United States federal law that aims to create a comprehensive regulatory framework for stablecoins. Stablecoins are a type of cryptocurrency that are backed by assets considered to be reliable such as a national currency or a commodity. Stablecoins are typically used to transfer funds between different cryptocurrency tokens.

Geotagged NFT

Geotagged non-fungible tokens (NFT) feature 3D versions of the street art alongside the corresponding geo-location. They allows art aficionados to own both the virtual and physical artwork without the need to remove the actual infrastructure it was originally painted on.

Moderate

Geth

Geth, short for Go Ethereum, is a command-line interface that allows developers to run full Ethereum nodes, mine the cryptocurrency and execute smart contracts.

Hard

The GOST hash function, defined in the standards GOST R 34.11-94 and GOST 34.311-95 is a 256-bit cryptographic hash function. It was initially defined in the Russian national standard GOST R 34.11-94 Information Technology – Cryptographic Information Security – Hash Function. The equivalent standard used by other member-states of the CIS is GOST 34.311-95.

Governance

In the world of cryptocurrencies, governance is defined as the people or organizations that have decision-making powers regarding the project.

Easy

Governance Token

A governance token is a token that can be used to vote on decisions that influence an ecosystem.

Moderate

GPG Encryption

GNU Privacy Guard (GPG) is a popular OpenPGP (Pretty Good Privacy) implementation. It is an open-source alternative to PGP that encrypts and signs communications and data securely.

Hard

GPU mining

GPU mining is the use of graphics processing units (GPUs) to "mine" proof-of-work cryptocurrencies, such as Bitcoin. Miners receive rewards for performing computationally intensive work, such as calculating hashes, that amend and verify transactions on an open and decentralized ledger. GPUs can be especially performant at calculating such hashes using math.

Graphical Processing Unit (GPU)

More commonly known as a graphics card, it is a computer chip that creates 3D images on computers, but has turned out to be efficient for mining cryptocurrencies.

Easy

Gray Swan Event

Gray swan is a significant event whose occurrence could be predicted, but the likelihood is low.

Easy

Greater Fool Theory

The greater fool theory was first discussed by professor Burton Malkiel. It suggests that there is always a “greater fool” that you can sell an overvalued asset to.

Easy

Green Candle

A green candle is an indication of the price closing higher than the opening price. The green candle is an indication that the overall sentiment of the market at the time of trading was bullish, or positive. A wide body with a small tail on top indicates a strong bullish movement in the market.

Easy

Grid Security Infrastructure

The Grid Security Infrastructure (GSI), formerly called the Globus Security Infrastructure, is a specification for secret, tamper-proof, delegatable communication between software in a grid computing environment. Secure, authenticatable communication is enabled using asymmetric encryption.

Gridcoin

Gridcoin is a cryptocurrency which rewards volunteer computing performed on the BOINC platform. BOINC was originally developed to support SETI@home, but has also been used for research in other areas.

Grøstl

Grøstl is a cryptographic hash function submitted to the NIST hash function competition by Praveen Gauravaram, Lars Knudsen, Krystian Matusiewicz, Florian Mendel, Christian Rechberger, Martin Schläffer, and Søren S. Thomsen. Grøstl was chosen as one of the five finalists of the competition. It uses the same S-box as AES in a custom construction. The authors claim speeds of up to 21.4 cycles per byte on an Intel Core 2 Duo, and 9.6 cycles/byte on an Intel i7 with AES-NI.

Group Domain of Interpretation

Group Domain of Interpretation or GDOI is a cryptographic protocol for group key management. The GDOI protocol is specified in an IETF Standard, RFC 6407, and is based on Internet Security Association and Key Management Protocol (ISAKMP), RFC 2408, and Internet Key Exchange version 1 (IKE). Whereas IKE is run between two peers to establish a "pair-wise security association", GDOI protocol is run between a group member and a "group controller/key server" (controller) and establishes a security association among two or more group members.

Group key

In cryptography, a group key is a cryptographic key that is shared between a group of users. Typically, group keys are distributed by sending them to individual users, either physically, or encrypted individually for each user using either that user's pre-distributed private key.

Group Mining

As opposed to solo mining, group mining is when multiple people mine together.

Moderate

Group signature

A group signature scheme is a method for allowing a member of a group to anonymously sign a message on behalf of the group. The concept was first introduced by David Chaum and Eugene van Heyst in 1991. For example, a group signature scheme could be used by an employee of a large company where it is sufficient for a verifier to know a message was signed by an employee, but not which particular employee signed it. Another application is for keycard access to restricted areas where it is inappropriate to track individual employee's movements, but necessary to secure areas to only employees in the group.

Gwei

The denomination used in defining the cost of gas in transactions involving Ether.

Moderate

H

H.235

H.235 covers security and encryption for H.323 and other H.245 based terminals.

Hacking

Hacking is the process of using a computer to manipulate another computer or computer system in an unauthorized fashion.

Moderate

A hard peg is an exchange rate policy, where a currency is set at a fixed rate against another currency.

Easy

Hardware random number generator

In computing, a hardware random number generator (HRNG), true random number generator (TRNG), non-deterministic random bit generator (NRBG), or physical random number generator is a device that generates random numbers from a physical process capable of producing entropy, unlike a pseudorandom number generator (PRNG) that utilizes a deterministic algorithm and non-physical nondeterministic random bit generators that do not include hardware dedicated to generation of entropy.

Hardware Security Module

A hardware security module is a type of computing device that secures digital keys and encrypts data.

Moderate

Hardware Wallet

A purpose-built physical device that stores private keys in a secure element and signs transactions without exposing the key material to a connected computer. The host machine sends an unsigned transaction to the hardware wallet; the device displays the details for confirmation, signs internally, and returns only the signature. SSP Wallet running on a dedicated phone achieves similar isolation through software and air-gap controls.

Beginner

Hardware-based encryption

Hardware-based encryption is the use of computer hardware to assist software, or sometimes replace software, in the process of data encryption. Typically, this is implemented as part of the processor's instruction set. For example, the AES encryption algorithm can be implemented using the AES instruction set on the ubiquitous x86 architecture. Such instructions also exist on the ARM architecture. However, more unusual systems exist where the cryptography module is separate from the central processor, instead being implemented as a coprocessor, in particular a secure cryptoprocessor or cryptographic accelerator, of which an example is the IBM 4758, or its successor, the IBM 4764. Hardware implementations can be faster and less prone to exploitation than traditional software implementations, and furthermore can be protected against tampering.

Harvest now, decrypt later

Harvest now, decrypt later (HNDL) is a surveillance strategy that relies on the acquisition and long-term storage of currently unreadable encrypted data awaiting possible breakthroughs in decryption technology that would render it readable in the future—a hypothetical date referred to as Y2Q, or Q-Day.

HAS-160

HAS-160 is a cryptographic hash function designed for use with the Korean KCDSA digital signature algorithm. It is derived from SHA-1, with assorted changes intended to increase its security. It produces a 160-bit output.

HAS-V

HAS-V is a cryptographic hash function with a variable output length. HAS-V is a hash function based on a block cipher. The hash function can produce hash values with lengths from 16 to 40 bytes.

Hash

A hash is the output result of a hashing algorithm, which creates a unique, fixed-length string to encrypt and secure a certain selection of arbitrary data.

Moderate

Hash calendar

A hash calendar is a data structure that is used to measure the passage of time by adding hash values to an append-only database with one hash value per elapsed second. It can be thought of special kind of Merkle or hash tree, with the property that at any given moment, the tree contains a leaf node for each second since 1970‑01‑01 00:00:00 UTC.

Hash Function

A deterministic function that maps arbitrary-length input data to a fixed-length output (digest) in a way that is fast to compute but infeasible to reverse. Bitcoin uses SHA-256 (double-hashed) for block mining and transaction IDs; Ethereum uses Keccak-256. Collision resistance — the inability to find two inputs that produce the same hash — is fundamental to blockchain integrity.

Beginner

Hash function security summary

This article summarizes publicly known attacks against cryptographic hash functions. Note that not all entries may be up to date. For a summary of other hash function parameters, see comparison of cryptographic hash functions.

Hash list

In computer science, a hash list is typically a list of hashes of the data blocks in a file or set of files. Lists of hashes are used for many different purposes, such as fast table lookup and distributed databases.

Hash Power / Hash Rate

A unit of measurement for the amount of computing power being consumed by the network to continuously operate.

Moderate

Hash-based cryptography

Hash-based cryptography is the generic term for constructions of cryptographic primitives based on the security of hash functions. It is of interest as a type of post-quantum cryptography.

Hashcash

Hashcash is a proof-of-work system used to limit email spam and denial-of-service attacks. Hashcash was proposed in 1997 by Adam Back and described more formally in Back's 2002 paper "Hashcash – A Denial of Service Counter-Measure". In Hashcash the client has to concatenate a random number with a string several times and hash this new string. It then has to do so over and over until a hash beginning with a certain number of zeros is found.

HashClash

HashClash was a volunteer computing project running on the Berkeley Open Infrastructure for Network Computing (BOINC) software platform to find collisions in the MD5 hash algorithm. It was based at Department of Mathematics and Computer Science at the Eindhoven University of Technology, and Marc Stevens initiated the project as part of his master's degree thesis.

Hashed Timelock Contract (HTLC)

A hashed timelock contract (HTLC) is an agreement between two parties that requires no trust between two users by offering special features to reduce risk.

Hard

Hashgraph Consensus Mechanism

The hashgraph consensus is an advanced and up-to-date version of the technology that enables consensus mechanisms.

Hard

Hashrate

The proof-of-work distributed computing schemes, including Bitcoin, frequently use cryptographic hashes as a proof-of-work algorithm. Hashrate is a measure of the total computational power of all participating nodes expressed in units of hash calculations per second. The hash/second units are small, so usually multiples are used, for large networks the preferred unit is terahash, for example, in 2023 the Bitcoin hashrate was about 300,000,000 terahashes per second.

Haskell Programming Language

The Haskell programming language is a standardized, general-purpose, statically-typed, purely functional programming language that came into existence in 1990.

Moderate

HAVAL

HAVAL is a cryptographic hash function. Unlike MD5, but like most modern cryptographic hash functions, HAVAL can produce hashes of different lengths – 128 bits, 160 bits, 192 bits, 224 bits, and 256 bits. HAVAL also allows users to specify the number of rounds to be used to generate the hash. HAVAL was broken in 2004.

HEAAN

HEAAN is an open source homomorphic encryption (HE) library which implements an approximate HE scheme proposed by Cheon, Kim, Kim and Song (CKKS). The first version of HEAAN was published on GitHub on 15 May 2016, and later a new version of HEAAN with a bootstrapping algorithm was released. Currently, the latest regular version is version 1.1 and the latest pre-release version is 2.1.

Hedera (distributed ledger)

Hedera Hashgraph, commonly known as Hedera, is a distributed ledger which uses a variant of proof of stake to reach consensus. The native cryptocurrency of the Hedera Hashgraph system is HBAR.

Hedge Contract

A hedge contract is a form of insurance that investors use to hedge against the risk of financial loss. Typically, a hedge is designed to protect against price fluctuations in the market.

Easy

Hedge Fund

A hedge fund is pooled investment fund that employs a number of investment strategies in a variety of liquid asset classes.

Moderate

Helium Network

The Helium Network is a wireless system composed of two distinct networks: one for Internet of things (IoT) devices using LoRaWAN and another for mobile phone coverage using Wi-Fi hotspots.

Hidden Cap

Hidden cap is an unknown limit to the amount of money a team elects to receive from investors in its initial coin offering (ICO). The purpose of a hidden cap is to even the playing field by letting smaller investors put in money, without the large investors forming an accurate understanding of the total cap and adjusting their investment as a result.

Moderate

Hierarchical Deterministic Wallet (HD Wallet)

A wallet that uses Hierarchical Deterministic (HD) protocol to support the generation of crypto-wallets from a single master seed using 12 mnemonic phrases. *see Deterministic Wallet.

Hard

High Assurance Internet Protocol Encryptor

A High Assurance Internet Protocol Encryptor (HAIPE) is a Type 1 encryption device that complies with the National Security Agency's HAIPE IS. The cryptography used is Suite A and Suite B, also specified by the NSA as part of the Cryptographic Modernization Program. HAIPE IS is based on IPsec with additional restrictions and enhancements. One of these enhancements includes the ability to encrypt multicast data using a "preplaced key". This requires loading the same key on all HAIPE devices that will participate in the multicast session in advance of data transmission. A HAIPE is typically a secure gateway that allows two enclaves to exchange data over an untrusted or lower-classification network.

Higher High

A higher high is when the price of a cryptocurrency closes higher than the previous day, which itself closed at a high.

Easy

Higher Low

A higher low is when the price of a cryptocurrency closes at a level that is higher than the close of the previous day.

Easy

History of bitcoin

Bitcoin is a cryptocurrency, a digital asset that uses cryptography to control its creation and management rather than relying on central authorities. Originally designed as a medium of exchange, Bitcoin is now primarily regarded as a store of value. The history of bitcoin started with its invention and implementation by Satoshi Nakamoto, who integrated many existing ideas from the cryptography community. Over the course of bitcoin's history, it has undergone rapid growth to become a significant store of value both on- and offline. From the mid-2010s, some businesses began accepting bitcoin in addition to traditional currencies.

HKDF

HKDF is a multi-purpose key derivation function (KDF) based on the HMAC message authentication code. HKDF follows "extract-then-expand" paradigm, where the KDF logically consists of two modules: the first stage takes the input keying material and "extracts" from it a fixed-length pseudorandom key, and then the second stage "expands" this key into several additional, independent pseudorandom keys as the output of the KDF.

HMAC

Hash-based Message Authentication Code — a construction that uses a cryptographic hash function together with a secret key to produce an authentication tag for a message. BIP-32 uses HMAC-SHA512 internally to derive child keys from a parent key and a derivation index. An HMAC tag verifies both the integrity and authenticity of data without requiring public-key operations.

Advanced

HODL

A type of passive investment strategy where you hold an investment for a long period of time, regardless of any changes in the price or markets. The term first became famous due to a typo made in a Bitcoin forum, and the term is now commonly expanded to stand for “Hold On for Dear Life.”

Easy

Hodlnaut

Hodlnaut is a Singapore-based cryptocurrency lending and borrowing platform that lost 69% of the cryptocurrencies that users deposited onto the platform.

Homomorphic encryption

Homomorphic encryption is a form of encryption that allows computations to be performed on encrypted data without first having to decrypt it. The resulting computations are left in an encrypted form which, when decrypted, result in an output that is identical to that of the operations performed on the unencrypted data. Homomorphic encryption can be used for privacy-preserving outsourced storage and computation. This allows data to be encrypted and outsourced to commercial cloud environments for processing, all while encrypted.

Honey encryption

Honey encryption is a type of data encryption that "produces a ciphertext, which, when decrypted with an incorrect key as guessed by the attacker, presents a plausible-looking yet incorrect plaintext."

Honeyminer

Honeyminer is a cryptocurrency mining app available for download on multiple devices.

Moderate

Honeypot

A honeypot is a scam used in the crypto industry to trap victims and steal their assets or sensitive information.

Easy

Host Identity Protocol

The Host Identity Protocol (HIP) is a host identification technology for use on Internet Protocol (IP) networks, such as the Internet. The Internet has two main name spaces, IP addresses and the Domain Name System. HIP separates the end-point identifier and locator roles of IP addresses. It introduces a Host Identity (HI) name space, based on a public key security infrastructure.

Hostage Byte Attack

A Hostage Byte Attack is a distributed denial of service (DDoS) attack against a user that stored its data on a malicious storage node and is asked to pay ransom to retrieve its data.

Moderate

Hosted Wallet

A wallet managed by a third-party service.

Moderate

Hot Storage

The online storage of private keys allowing for quicker access to cryptocurrencies. *see Cold Storage.

Easy

Hot Wallet

A wallet whose private key is held on a device with an active internet connection, such as a mobile app or browser extension. Hot wallets are convenient for frequent transactions but expose the key to network-based attacks. SSP mitigates the hot-wallet risk by requiring a second independent device signature before any transaction is valid.

Beginner

Howey Test

A test used to determine whether or not an asset is a security.

Easy

HTC Exodus

HTC Exodus 1 is an entry level 2019 HTC U series engineering based Android OS powered blockchain-secured "hardware cryptocurrency wallet" mobile phone developed by HTC Corporation. Its default web browser application is Brave and it runs DApps through a partnership with Opera.

HTTP Strict Transport Security

HTTP Strict Transport Security (HSTS) is a policy mechanism that helps to protect websites against man-in-the-middle attacks such as protocol downgrade attacks and cookie hijacking. It allows web servers to declare that web browsers should automatically interact with it using only HTTPS connections, which provide Transport Layer Security (TLS/SSL), unlike the insecure HTTP used alone. HSTS is an IETF standards track protocol and is specified in RFC 6797.

HTTP/1.1 Upgrade header

The Upgrade header field is an HTTP header field introduced in HTTP/1.1. In the exchange, the client begins by making a cleartext request, which is later upgraded to a newer HTTP protocol version or switched to a different protocol. A connection upgrade must be requested by the client; if the server wants to enforce an upgrade it may send a 426 Upgrade Required response. The client can then send a new request with the appropriate upgrade headers while keeping the connection open.

HTTPS

Hypertext Transfer Protocol Secure (HTTPS) is an extension of the Hypertext Transfer Protocol (HTTP). It uses encryption for secure communication over a computer network, and is widely used on the Internet. In HTTPS, the communication protocol is encrypted using Transport Layer Security (TLS) or, formerly, Secure Sockets Layer (SSL). The protocol is therefore also referred to as HTTP over TLS, or HTTP over SSL.

HTX (cryptocurrency exchange)

HTX, formerly known as Huobi, is a Seychelles-based cryptocurrency exchange. Founded in China,, HTX now has offices in Hong Kong, South Korea, Japan and the United States. In August 2018, it became a publicly listed Hong Kong company. According to Bloomberg, it is owned by cryptocurrency billionaire Justin Sun.

Hub Culture

Hub Culture is a digital identity and collaboration network founded in November 2002 by Stan Stalnaker, based on his book of the same name published that year. It is headquartered in Bermuda and operates a technology ecosystem encompassing digital currency, digital identity, and physical collaboration spaces known as Pavilions. The network has been covered by the Wall Street Journal, Wired, CNN, and Finextra, among other publications. Founder Stan Stalnaker’s essay on peer-to-peer networks was named the lead Breakthrough Idea of 2008 by the Harvard Business Review, where he described a coming economy in which consumers become consumer-producers. Hub Culture launched Ven, its digital currency, in July 2007. Ven was the first digital currency to be listed for pricing on the Thomson Reuters terminal network, and was the first virtual currency used for consumer retail transactions at physical locations worldwide. In 2010, Hub Culture added carbon to Ven’s underlying basket of currencies and commodities, making it one of the first environmentally linked digital currencies.

Human Keys

Human Keys are cryptographic keys derived from what you are, what you know, or what you have. They are used to secure digital assets, protect privacy, and access the decentralized web.

Easy

Human rights and encryption

Human rights and encryption refers to the ways in which digital encryption affects human rights. Encryption can be used as both a detriment and a boon to human rights; for example, encryption can be used to enforce digital rights management for video games. This kind of video game licensing can render software unusable long term and represents the erosion of consumer rights. At the same time, encryption is fundamental part of internet security. Asymmetrical encryption is used extensively online for authentication, providing users confidence their internet traffic is not being misdirected. Encryption is also used to obfuscate information as it travels from end-to-end over the internet, preventing eavesdropping and tampering. Encryption can also provide anonymity, which is an important consideration for freedom of expression. Despite its drawbacks, encryption is essential for a free, open, and trustworthy internet.

Human-Readable Names

In computer programming, human-readable refers to making information able to be read naturally by humans and stands in opposition to machine-readable format - i.e binary.

Easy

Huobi BTC (HBTC)

Launched by Huobi, Huobi BTC or HBTC is a standard ERC-20 token pegged to BTC on a 1:1 ratio.

Easy

Hybrid argument (cryptography)

In cryptography, the hybrid argument is a proof technique used to show that two distributions are computationally indistinguishable.

Hybrid cryptosystem

In cryptography, a hybrid cryptosystem is one which combines the convenience of a public-key cryptosystem with the efficiency of a symmetric-key cryptosystem. Public-key cryptosystems are convenient in that they do not require the sender and receiver to share a common secret in order to communicate securely. However, they often rely on complicated mathematical computations and are thus generally much more inefficient than comparable symmetric-key cryptosystems. In many applications, the high cost of encrypting long messages in a public-key cryptosystem can be prohibitive. This is addressed by hybrid systems by using a combination of both.

Hybrid PoW/PoS

A hybrid PoW/PoS allows for both proof-of-stake and proof-of-work as consensus distribution algorithms on the network. This approach aims to bring together the security of PoW consensus and the governance and energy efficiency of PoS.

Moderate

Hydra (Cardano)

Hydra is a layer-two scaling solution for the Cardano blockchain that aims to increase the transaction processing capacity of the network by allowing multiple heads or channels.

Hard

HypeLab

HypeLab is a cryptocurrency advertising network. It programmatically operates a two-sided marketplace connecting advertisers with web publishers, using proprietary technology for ad targeting and optimization.

Hyper-encryption

Hyper-encryption is a form of encryption invented by Michael O. Rabin which uses a high-bandwidth source of public random bits, together with a secret key that is shared by only the sender and recipient(s) of the message. It uses the assumptions of Ueli Maurer's bounded-storage model as the basis of its secrecy. Although everyone can see the data, decryption by adversaries without the secret key is still not feasible, because of the space limitations of storing enough data to mount an attack against the system.

Hyperbridge

Hyperbridge is a cross-chain interoperability bridge that uses cryptographic protocols to facilitate the transfer of assets and data between different blockchains. Hyperbridge was launched on Polkadot mainnet in 2024 by Polytope Labs. The protocol is designed with a decentralised verification system which eliminates traditional reliance on blockchain validators, addressing the limitations of traditional bridges.

Hyperelliptic curve cryptography

Hyperelliptic curve cryptography is similar to elliptic curve cryptography (ECC) insofar as the Jacobian of a hyperelliptic curve is an abelian group in which to do arithmetic, just as we use the group of points on an elliptic curve in ECC.

Hyperinflation

Hyperinflation is defined as unrestricted growth in prices for goods and services in an economy. It happens when resources become limited, such as gas or food, and prices rise as demand outstrips supply.

Easy

Hyperledger (Hyperledger Foundation)

Hyperledger is an umbrella project of open source blockchains and blockchain-related tools started by the Linux Foundation in 2015 to support the collaborative development of blockchain-based distributed ledgers.

Easy

HyperVerse

HyperVerse is a defunct cryptocurrency hedge fund. The collapse of the company resulted in approximately $1.3 billion in customer losses.

I

ICON (blockchain platform)

ICON is a decentralized, open-source blockchain with smart contract functionality. ICX is the native cryptocurrency of the platform.

Identity-based conditional proxy re-encryption

Identity-based conditional proxy re-encryption (IBCPRE) is a type of proxy re-encryption (PRE) scheme in the identity-based public key cryptographic setting. An IBCPRE scheme is a natural extension of proxy re-encryption on two aspects. The first aspect is to extend the proxy re-encryption notion to the identity-based public key cryptographic setting. The second aspect is to extend the feature set of proxy re-encryption to support conditional proxy re-encryption. By conditional proxy re-encryption, a proxy can use an IBCPRE scheme to re-encrypt a ciphertext but the ciphertext would only be well-formed for decryption if a condition applied onto the ciphertext together with the re-encryption key is satisfied. This allows fine-grained proxy re-encryption and can be useful for applications such as secure sharing over encrypted cloud data storage.

Identity-based cryptography

Identity-based cryptography is a type of public-key cryptography in which a publicly known string representing an individual or organization is used as a public key. The public string could include an email address, domain name, or a physical IP address.

Identity-based encryption

Identity-based encryption (IBE), is an important primitive of identity-based cryptography. As such it is a type of public-key encryption in which the public key of a user is some unique information about the identity of the user. This means that a sender who has access to the public parameters of the system can encrypt a message using e.g. the text-value of the receiver's name or email address as a key. The receiver obtains its decryption key from a central authority, which needs to be trusted as it generates secret keys for every user.

IEEE 802.11i-2004

IEEE 802.11i-2004, or 802.11i for short, is an amendment to the original IEEE 802.11, implemented as Wi-Fi Protected Access II (WPA2). The draft standard was ratified on 24 June 2004. This standard specifies security mechanisms for wireless networks, replacing the short Authentication and privacy clause of the original standard with a detailed Security clause. In the process, the amendment deprecated broken Wired Equivalent Privacy (WEP), while it was later incorporated into the published IEEE 802.11-2007 standard.

Immutable

A property that defines the inability to be changed, especially over time.

Easy

Impact of non-fungible tokens on traditional businesses

The impact of Non-Fungible Tokens (NFTs) on traditional businesses is quantifiable in several distinct operational, transactional, and economic variables within multiple industry sectors. NFTs, characterized by their indivisibility and uniqueness, are registered on a blockchain.

Impermanent Loss

Impermanent loss is when a liquidity provider has a temporary loss of funds because of volatility in a trading pair.

Moderate

Implicit certificate

In cryptography, implicit certificates are a variant of public key certificate. A subject's public key is reconstructed from the data in an implicit certificate, and is then said to be "implicitly" verified. Tampering with the certificate will result in the reconstructed public key being invalid, in the sense that it is infeasible to find the matching private key value, as would be required to make use of the tampered certificate.

In-the-Money / Out-of-the-Money

In-the-money and out-of-the-money are options trading mechanisms that allow investors to benefit from additional tools to work with the market.

Moderate

Independent Reserve

Independent Reserve is an Australian-based digital currency exchange founded in 2013. They are an order book exchange and an OTC desk.

Indistinguishability obfuscation

In cryptography, indistinguishability obfuscation is a type of software obfuscation with the defining property that obfuscating any two programs that compute the same mathematical function results in programs that cannot be distinguished from each other. Informally, such obfuscation hides the implementation of a program while still allowing users to run it. Formally, iO satisfies the property that obfuscations of two circuits of the same size which implement the same function are computationally indistinguishable.

Infinite Approval

Pre-approving smart contracts to enable the platform to spend any amount of your coins.

Moderate

Infinite Mint Attack

An infinite mint attack occurs when an unwanted entity or hacker mints an absurd ("infinite") amount of tokens within a protocol.

Hard

Inflation

A general increase in prices and fall in the purchasing value of money.

Easy

Information leakage

Information leakage happens whenever a system that is designed to be closed to an eavesdropper reveals some information to unauthorized parties nonetheless. In other words: Information leakage occurs when secret information correlates with, or can be correlated with, observable information. For example, when designing an encrypted instant messaging network, a network engineer without the capacity to crack encryption codes could see when messages are transmitted, even if he could not read them.

Information security

Information security or data security (infosec) is the practice of protecting information by mitigating information risks. It is part of information risk management. It typically involves preventing or reducing the probability of unauthorized or inappropriate access to data or the unlawful use, disclosure, disruption, deletion, corruption, modification, inspection, recording, or devaluation of information. It also involves actions intended to reduce the adverse impacts of such incidents. Protected information may take any form, e.g., electronic or physical, tangible, or intangible. Information security's primary focus is the balanced protection of data confidentiality, integrity, and availability while maintaining a focus on efficient policy implementation, all without hampering organization productivity. This is largely achieved through a structured risk management process.

Initial Bounty Offering (IBO)

A novel way of launching a project that focuses on people contributing skills to a platform rather than money.

Moderate

In cryptography, an initialization vector (IV) or starting variable is an input to a cryptographic primitive being used to provide the initial state. The IV is typically required to be random or pseudorandom, but sometimes an IV only needs to be unpredictable or unique. Randomization is crucial for some encryption schemes to achieve semantic security, a property whereby repeated usage of the scheme under the same key does not allow an attacker to infer relationships between segments of the encrypted message. For block ciphers, the use of an IV is described by the modes of operation.

An internal transaction, also known as a "message," is a byproduct of an EOA interaction with a contract address that results in Ether being transferred.

Easy

Internet Key Exchange

In computing, Internet Key Exchange is the protocol used to set up a security association (SA) in the IPsec protocol suite. IKE builds upon the Oakley protocol and ISAKMP. IKE uses X.509 certificates for authentication ‒ either pre-shared or distributed using DNS ‒ and a Diffie–Hellman key exchange to set up a shared session secret from which cryptographic keys are derived. A IETF draft is currently being written to provide a quantum-resistant key establishment using ML-KEM. In addition, a security policy for every peer which will connect must be manually maintained.

Internet Layer

Internet layer is the third layer in the TCP/IP model and is responsible for the transportation of network packets.

Hard

Internet Memes

A meme is an image, a video, or a piece of text that is copied and spread rapidly by internet users. They are typically humorous but can also be critical as well.

Easy

Internet of Things

Internet of Things (IoT) is a global interconnected network of devices, sensors and software that can collect and exchange data with each other in real-time over the Internet.

Easy

Internet Security Association and Key Management Protocol

Internet Security Association and Key Management Protocol (ISAKMP) is a protocol defined by RFC 2408 for establishing security association (SA) and cryptographic keys in an Internet environment. ISAKMP only provides a framework for authentication and key exchange and is designed to be key exchange independent; protocols such as Internet Key Exchange (IKE) and Kerberized Internet Negotiation of Keys (KINK) provide authenticated keying material for use with ISAKMP. For example: IKE describes a protocol using part of Oakley and part of SKEME in conjunction with ISAKMP to obtain authenticated keying material for use with ISAKMP, and for other security associations such as AH and ESP for the IETF IPsec DOI.

Internet Service Provider (ISP)

Internet Service Providers (ISPs) are commercial entities that provide end-users with access to the internet.

Hard

InternetCash.com

InternetCash.com was a company that generated pre-paid cards, either in physical or electronic form, to distribute cash. The cash consisted of an InternetCash number together with a customer-selected PIN. The InternetCash e-currency could then be spent with participating online merchants. An early name for InternetCash, before it acquired the internetcash.com domain name, was SpendCash.com.

Interoperability

Blockchain interoperability, or cross-chain interoperability, is the ability to see and share information across multiple blockchains.

Moderate

InterPlanetary File System (IPFS)

The InterPlatery File System is a peer-to-peer, distributed system for storing and accessing files, as well as websites and applications, which relies on content addressing rather than location.

Moderate

Intrinsic Value

The intrinsic value of an asset depicts the asset’s actual worth based on a complex financial calculation rather than its current price.

IP addresses are unique numeric addresses assigned to devices connected to the internet or a local network.

Hard

IPsec

In computing, Internet Protocol Security (IPsec) is a secure network protocol suite that authenticates and encrypts packets of data to provide secure encrypted communication between two computers over an Internet Protocol network. It is used in virtual private networks (VPNs).

Iron Finance

Iron Finance was a decentralized finance (DeFi) protocol on the Polygon blockchain.

Isolated Margin

This mode is useful for traders who want to take speculative positions, and where there is a probable chance of their speculation turning out to be incorrect. In such a situation, the user will be better protected as compared to cross-margin mode because only their isolated margin balance will face liquidation, instead of their entire margin balance. The downside of using isolated margin is that your exposure will be limited to one position in a particular market.

Moderate

J

Jager

The smallest denomination of Binance Coin (BNB) is called Jager.

Easy

James Howells

James Howells is a Welsh entrepreneur and information technology specialist, best known for accidentally discarding a hard drive containing 7,500 bitcoins, now worth hundreds of millions of dollars. He is currently founding a new technology company focused on blockchain solutions and digital security known as Ceiniog Coin.

Java

Java is a general-purpose, class-based as well as object-oriented programming language.

Easy

Java KeyStore

A Java KeyStore (JKS) is a repository of security certificates – either authorization certificates or public key certificates – plus corresponding private keys, used for instance in TLS encryption.

JavaScript

JavaScript is a powerful, dynamic, lightweight, and advanced programming language. It is mostly used in web-based applications.

Hard

Jeevan Pramaan

Jeevan Pramaan is an Indian Life Certificate program affiliated with Aadhaar for people with pensions. It was started by Prime Minister Narendra Modi on 10 November 2014.

JH (hash function)

JH is a cryptographic hash function submitted to the NIST hash function competition by Hongjun Wu. Though chosen as one of the five finalists of the competition, in 2012 JH ultimately lost to NIST hash candidate Keccak. JH has a 1024-bit state, and works on 512-bit input blocks. Processing an input block consists of three steps:XOR the input block into the left half of the state. Apply a 42-round unkeyed permutation (encryption function) to the state. This consists of 42 repetitions of: Break the input into 256 4-bit blocks, and map each through one of two 4-bit S-boxes, the choice being made by a 256-bit round-dependent key schedule. Equivalently, combine each input block with a key bit, and map the result through a 5→4 bit S-box. Mix adjacent 4-bit blocks using a maximum distance separable code over GF(24). Permute 4-bit blocks so that they will be adjacent to different blocks in following rounds. XOR the input block into the right half of the state.

JioSphere

JioSphere Browser is a web browser developed by Jio Platforms, a subsidiary of Reliance Industries Limited, an Indian multinational conglomerate. The browser is designed to provide a localized and integrated internet browsing experience for users, particularly within the Jio digital ecosystem. It is available for multiple platforms, including mobile devices and smart TVs.

JOMO

Joy of missing out (JOMO) is the opposite of having a fear of missing out (FOMO.)

Easy

JPM Coin

JPM Coin is a dollar-backed cryptocurrency (stablecoin) from the bank JPMorgan Chase, announced in February 2019 as an institution-to-institution service.

JSON Web Encryption

JSON Web Encryption (JWE) is an IETF standard providing a standardized syntax for the exchange of encrypted data, based on JSON and Base64. It is defined by RFC 7516. Along with JSON Web Signature (JWS), it is one of the two possible formats of a JWT. JWE forms part of the JavaScript Object Signing and Encryption (JOSE) suite of protocols.

K

KCDSA

KCDSA is a digital signature algorithm created by a team led by the Korea Internet & Security Agency (KISA). It is an ElGamal variant, similar to the Digital Signature Algorithm and GOST R 34.10-94. The standard algorithm is implemented over , but an elliptic curve variant (EC-KCDSA) is also specified.

Kerberized Internet Negotiation of Keys

Kerberized Internet Negotiation of Keys (KINK) is a protocol defined in RFC 4430 used to set up an IPsec security association (SA), similar to Internet Key Exchange (IKE), utilizing the Kerberos protocol to allow trusted third parties to handle authentication of peers and management of security policies in a centralized fashion.

Kerckhoffs's principle

Kerckhoffs's principle of cryptography was stated by the Dutch cryptographer Auguste Kerckhoffs in the 19th century. The principle holds that a cryptosystem should be secure, even if everything about the system, except the key, is public knowledge. This concept is widely embraced by cryptographers, in contrast to security through obscurity, which is not.

Key (cryptography)

A key in cryptography is a piece of information, usually a string of numbers or letters that are stored in a file, which, when processed through a cryptographic algorithm, can encode or decode cryptographic data. Based on the used method, the key can be different sizes and varieties, but in all cases, the strength of the encryption relies on the security of the key being maintained. A key's security strength is dependent on its algorithm, the size of the key, the generation of the key, and the process of key exchange.

Key Derivation

The process of computing a cryptographic key from source material — a password, a seed, or a parent key — using a deterministic algorithm. BIP-32 key derivation uses HMAC-SHA512 to derive child private and public keys from a parent extended key. Key derivation functions (KDFs) like PBKDF2 are also used to stretch a BIP-39 mnemonic into the 512-bit seed before HD derivation begins.

Advanced

Key exchange

Key exchange is a method in cryptography by which cryptographic keys are exchanged between two parties, allowing use of a cryptographic algorithm.

Key Management Interoperability Protocol

The Key Management Interoperability Protocol (KMIP) is an extensible communication protocol that defines message formats for the manipulation of cryptographic keys on a key management server. This facilitates data encryption by simplifying encryption key management. Keys may be created on a server and then retrieved, possibly wrapped by other keys. Both symmetric and asymmetric keys are supported, including the ability to sign certificates. KMIP also allows for clients to ask a server to encrypt or decrypt data, without needing direct access to the key.

Key Transparency

Key Transparency allows communicating parties to verify public keys used in end-to-end encryption. In many end-to-end encryption services, to initiate communication a user will reach out to a central server and request the public keys of the user with which they wish to communicate. If the central server is malicious or becomes compromised, a man-in-the-middle attack can be launched through the issuance of incorrect public keys. The communications can then be intercepted and manipulated. Additionally, legal pressure could be applied by surveillance agencies to manipulate public keys and read messages.

Key-agreement protocol

In cryptography, a key-agreement protocol is a protocol whereby two parties generate a cryptographic key as a function of information provided by each honest party so that no party can predetermine the resulting value. In particular, all honest participants influence the outcome. A key-agreement protocol is a specialisation of a key-exchange protocol.

Key-based routing

Key-based routing (KBR) is a lookup method used in conjunction with distributed hash tables (DHTs) and certain other overlay networks. While DHTs provide a method to find a host responsible for a certain piece of data, KBR provides a method to find the closest host for that data, according to some defined metric. This may not necessarily be defined as physical distance, but rather the number of network hops.

Keylogger

A keylogger or keystroke logging software is a spying tool often used by hackers to record keystrokes made by users.

Moderate

Keyring (cryptography)

In cryptography, a keyring stores known encryption keys. For example, GNU Privacy Guard makes use of keyrings.

KillRoy Was Here

KillRoy Was Here is a 2022 American comedy horror anthology film directed by Kevin Smith, who co-wrote it with Andrew McElfresh. The film stars Azita Ghanizada, Ryan O'Nan, Harley Quinn Smith, Chris Jericho, Justin Kucsulain, Jason Mewes, and Ralph Garman.

Kimchi Premium

Kimchi premium is a phenomenon occurring in South Korean crypto exchanges, making valuations appear higher than on other international exchanges.

Easy

Klinger Oscillator

The Klinger volume oscillator is a volume-based technical indicator that compares volume to price to forecast price reversals in the financial markets.

Hard

KLJN Secure Key Exchange

Random-resistor-random-temperature Kirchhoff-law-Johnson-noise key exchange, also known as RRRT-KLJN or simply KLJN, is an approach for distributing cryptographic keys between two parties that claims to offer unconditional security. This claim, which has been contested, is significant, as the only other key exchange approach claiming to offer unconditional security is Quantum key distribution.

Knapsack cryptosystems

Knapsack cryptosystems are cryptosystems whose security is based on the hardness of solving the knapsack problem. They remain quite unpopular because simple versions of these algorithms have been broken for several decades. However, that type of cryptosystem is a good candidate for post-quantum cryptography.

Knapsack problem

The knapsack problem is the following problem in combinatorial optimization:Given a set of items, each with a weight and a value, determine which items to include in the collection so that the total weight is less than or equal to a given limit and the total value is as large as possible.

Know Your Customer (KYC)

Short for Know Your Customer, these are checks that crypto exchanges and trading platforms must complete to verify the identity of their customers.

Easy

Kodak KashMiner

The Kodak KashMiner was a Bitcoin mining computer that was displayed at Kodak's booth at the Consumer Electronics Show in January 2018. It was promoted by Spotlite USA, who had previously licensed the Kodak name for Kodak-branded LED lighting. The initiative was not endorsed by Eastman Kodak.

KodakCoin

KodakCoin was a Kodak-branded blockchain cryptocurrency, used to plan payments for licensed photographers. It was also able to generate individualized cryptocurrency for its users through Kodak KashMiner, a Bitcoin-mining computer. Critics characterized Kodak's association with the cryptocurrency as a "desperate money grab."

Kraken (cryptocurrency exchange)

Kraken is a US-based cryptocurrency exchange, founded in 2011. It is the first cryptocurrency company to obtain a bank charter. In 2025, Kraken began allowing the trading of tokenized equities by non-US customers.

Kruskal count

The Kruskal count is a probabilistic concept originally demonstrated by the Russian mathematician Evgenii Borisovich Dynkin in the 1950s or 1960s discussing coupling effects and rediscovered as a card trick by the American mathematician Martin David Kruskal in the early 1970s as a side-product while working on another problem. It was published by Kruskal's friend Martin Gardner and magician Karl Fulves in 1975. This is related to a similar trick published by magician Alexander F. Kraus in 1957 as Sum total and later called Kraus principle.

KuCoin

KuCoin is a Seychelles-based cryptocurrency exchange. It was founded in China in 2017, but was later moved to Singapore following the Chinese government's restrictions on cryptocurrency companies, and subsequently to the Seychelles.

Kuna (company)

Kuna is the first Ukrainian and CIS cryptocurrency exchange.

Kupyna

Kupyna is a cryptographic hash function defined in the Ukrainian national standard DSTU 7564:2014. It was created to replace an obsolete GOST hash function defined in the old standard GOST 34.11-95, similar to Streebog hash function standardized in Russia.

Kurzsignale

The Short Signal Code, also known as the Short Signal Book, was a short code system used by the Kriegsmarine during World War II to minimize the transmission duration of messages.

L

L3cos

L3COS is an algorithm for digitising processes based on Blockchain, which has a three-level structure and is distributed as Platform as a Service for state bodies and businesses. The algorithm is based on the blockchain, in which any decision made at any of the levels will become part of the common chain. The technology involves a three-level framework that provides national governments, businesses, and private individuals with the tools to create a digital economy that does not allow fraudulent activity, financial or otherwise.

A layer-1 blockchain is a set of solutions that improve the base protocol itself

Moderate

LBRY

LBRY is a blockchain-based file-sharing and payment network that is primarily used for social networks and video platforms.

Leased Proof of Stake (LPoS)

Leased Proof of Stake (LPoS) is a consensus mechanism that allows cryptocurrency holders to lease their coins to nodes on a network.

Easy

Ledger

A record of financial transactions that cannot be changed, only appended with new transactions.

Easy

Legality of cryptocurrency by country or territory

The legal status of cryptocurrencies varies substantially from one jurisdiction to another, and is still undefined or changing in many of them. While in the majority of countries the usage of cryptocurrency is not in itself illegal, its status and usability as a means of payment varies, with differing regulatory implications.

Letter frequency

Letter frequency is the number of times letters of the alphabet appear on average in written language. Letter frequency analysis dates back to the Arab mathematician Al-Kindi, who formally developed the method to break ciphers. Letter frequency analysis gained importance in Europe with the development of movable type in AD 1450, wherein one must estimate the amount of type required for each letterform. Linguists use letter frequency analysis as a rudimentary technique for language identification, where it is particularly effective as an indication of whether an unknown writing system is alphabetic, syllabic, or logographic.

Leverage

Money that a trader borrows from a brokerage, enabling them to gain far greater exposure to a position than what their capital allows.

Moderate

Leveraged Tokens

In the world of cryptocurrencies, leveraged tokens give you a leveraged position in trading, meaning that your earnings and losses are multiplied.

Moderate

LINK is an Ethereum-based token that is used to pay Chainlink node operators.

Moderate

Litecoin is a cryptocurrency and open-source software project. Litecoin was the first cryptocurrency after bitcoin, starting in October 2011.

Liveness

A guarantee that a system will continue to provide data, and that no centralized authority can shut down its services.

Moderate

LMD GHOST

LMD GHOST (aka the GHOST Protocol) is a fork-choice rule that allows the nodes in a blockchain network to reach an agreement on the valid state of the ledger.

Easy

Loan-to-value (LTV)

Used by lenders, loan-to-value (LTV) is the assessment ratio of risk involved while approving a loan. Simply, it is the ratio of the loan's value to the value of the collateral.

Hard

A lower low is when the price of a cryptocurrency closes lower than the previous day, which itself closed at a low.

Easy

LSH (hash function)

LSH is a cryptographic hash function designed in 2014 by South Korea to provide integrity in general-purpose software environments such as PCs and smart devices. LSH is one of the cryptographic algorithms approved by the Korean Cryptographic Module Validation Program (KCMVP). And it is the national standard of South Korea.

Luke Dashjr

Luke Dashjr is an American software developer known for his long-standing role in the development of Bitcoin Core and for co-founding the Bitcoin mining pool Ocean.

Lyn Alden

Lyn Alden is an American investment strategist and founder of Lyn Alden Investment Strategy. She is known for her macroeconomic analysis of U.S. equities and international market trends. She is also known for her analysis and advocacy of Bitcoin and has been a speaker at the Bitcoin Conference.

M

M-of-N Multisig

A generalized multisig scheme requiring M signatures from a set of N cosigners before a transaction is valid. A 2-of-3 setup, for example, tolerates one lost key while still requiring two out of three participants to agree on a spend. SSP uses a 2-of-2 variant — the strictest form — so both devices must sign every transaction.

Beginner

Mainchain

A mainchain is the base blockchain layer where all transactions are processed and finalized.

Moderate

Mainnet

An independent blockchain running its own network with its own technology and protocol.

Easy

Mainnet Swap

Mainnet swap refers to the shift of a cryptocurrency project from one blockchain network to another (which in most cases is its own native blockchain network).

Easy

Maker Protocol (MakerDAO)

The Maker Protocol allows users to leverage their assets as collateral that are approved by the Maker governance in order to get rewarded with DAI.

Moderate

Malicious DApp

A decentralized application designed to trick users into signing transactions that drain their wallet or grant unlimited token approvals to attacker-controlled contracts. Malicious DApps often impersonate legitimate protocols through typosquatted domains or compromised front-ends. SSP's co-signing model provides a second review point: both devices must confirm the transaction data before it is broadcast.

Moderate

Malleability (cryptography)

Malleability is a property of some cryptographic algorithms. An encryption algorithm is said to be malleable if it is possible to transform a ciphertext into another ciphertext which decrypts to a related plaintext. That is, given an encryption of a plaintext , it is possible to generate another ciphertext which decrypts to , for a known function , without necessarily knowing or learning .

Malware

Malware or malicious software refers to harmful programs utilized by bad actors to illegally access and/or compromise a computer, network or server.

Easy

Man-in-the-Middle Attack (MITM)

a man-in-the-middle attack (MITM) attack is a general term for a cyberattack where a perpetrator positions himself in a conversation between two parties either to secretly eavesdrop.

Moderate

Markets in Crypto-Assets is a regulation in European Union (EU) law. It is intended to help streamline the adoption of blockchain and distributed ledger technology (DLT) as part of virtual asset regulation in the EU, while protecting users and investors.

Markets in Crypto-Assets (MiCA)

The Markets in Crypto-Assets (MiCA) regulation is a comprehensive regulatory framework instituted by the European Union (EU) to govern the issuance, trading, and provision of services related to crypto.

Easy

Marlowe

Developed by Input Output Hong Kong (IOHK), Marlowe is an easy-to-use programming language for experts with no programming expertise or knowledge, enabling them to write smart contracts for financial products.

Moderate

MASH-1

For a cryptographic hash function, a MASH-1 is a hash function based on modular arithmetic.

Mask generation function

A mask generation function (MGF) is a cryptographic primitive similar to a cryptographic hash function except that while a hash function's output has a fixed size, a MGF supports output of a variable length. In this respect, a MGF can be viewed as a extendable-output function (XOF): it can accept input of any length and process it to produce output of any length. Mask generation functions are completely deterministic: for any given input and any desired output length the output is always the same.

Master/Session

In cryptography, Master/Session is a key management scheme in which a pre-shared Key Encrypting Key is used to encrypt a randomly generated and insecurely communicated Working Key. The Working Key is then used for encrypting the data to be exchanged. Its advantage is simplicity, but it suffers the disadvantage of having to communicate the pre-shared Key Exchange Key, which can be difficult to update in the event of compromise.

Masternodes

Masternodes are a server maintained by its owner, somewhat like full nodes, but with additional functionalities such as anonymizing transactions, clearing transactions, and participating in governance and voting. It was initially popularized by Dash to reward owners of these servers for maintaining a service for the blockchain.

Moderate

Max Supply

The best approximation of the maximum amount of coins that will ever exist in the lifetime of the cryptocurrency. *see Circulating Supply and Total Supply.

Moderate

Maximal Extractable Value (MEV)

Maximal extractable value (MEV) is a measure of the profit a miner can make through their ability to arbitrarily include, exclude, or re-order transactions within the blocks they produce.

Hard

MazaCoin

MazaCoin is a cryptocurrency launched in 2014 by developer Payu Harris. It was created with the goal of providing a digital currency for the Oglala Lakota tribe in South Dakota.

MD2 (hash function)

The MD2 Message-Digest Algorithm is an obsolete cryptographic hash function developed by Ronald Rivest in 1989. The algorithm is optimized for 8-bit computers. MD2 is specified in IETF RFC 1319. The "MD" in MD2 stands for "Message Digest".

MD4

The MD4 Message-Digest Algorithm is a cryptographic hash function developed by Ronald Rivest in 1990. The digest length is 128 bits. The algorithm has influenced later designs, such as the MD5, SHA-1 and RIPEMD algorithms. The initialism "MD" stands for "Message Digest".

MD5

The MD5 message-digest algorithm is a widely used hash function producing a 128-bit hash value. MD5 was designed by Ronald Rivest in 1991 to replace an earlier hash function MD4, and was specified in 1992 as RFC 1321.

MD6

The MD6 Message-Digest Algorithm is a cryptographic hash function. It uses a Merkle tree-like structure to allow for immense parallel computation of hashes for very long inputs. Authors claim a performance of 28 cycles per byte for MD6-256 on an Intel Core 2 Duo and provable resistance against differential cryptanalysis. The source code of the reference implementation was released under MIT license.

MDC-2

In cryptography, MDC-2 is a cryptographic hash function. MDC-2 is a hash function based on a block cipher with a proof of security in the ideal-cipher model. The length of the output hash depends on the underlying block cipher used.

MDS matrix

An MDS matrix is a matrix representing a function with certain diffusion properties that have useful applications in cryptography. Technically, an matrix over a finite field is an MDS matrix if it is the transformation matrix of a linear transformation from to such that no two different -tuples of the form coincide in or more components. Equivalently, the set of all -tuples is an MDS code, i.e., a linear code that reaches the Singleton bound.

Medium of Exchange

A medium of exchange can be seen as an intermediary instrument or system that is used to facilitate a sale, purchase or even trade of goods between parties.

Moderate

Megahashes Per Second

Megahashes per second (MH/s) is a unit of measurement that equals one million hashes per second.

Hard

Meme coin

A meme coin is a cryptocurrency that originated from an internet meme or has some other humorous characteristic.

Meme Economy

Merkle Root

A single 32-byte hash that commits to all transactions in a block by repeatedly hashing pairs of transaction hashes up a binary tree. The Merkle root is stored in the block header; changing any transaction would change the root and invalidate the block's proof-of-work. It allows efficient proof of transaction inclusion without downloading the full block.

Advanced

Merkle signature scheme

In hash-based cryptography, the Merkle signature scheme is a digital signature scheme based on Merkle trees and one-time signatures such as the Lamport signature scheme. It was developed by Ralph Merkle in the late 1970s and is an alternative to traditional digital signatures such as the Digital Signature Algorithm or RSA. NIST has approved specific variants of the Merkle signature scheme in 2020.

Merkle Tree

A tree structure in cryptography, in which every leaf node is labelled with the hash of a data block and every non-leaf node is labelled with the cryptographic hash of the labels of its child nodes. Hash trees allow efficient and secure verification of the contents of blockchains, as each change propagates upwards so verification can be done by simply looking at the top hash.

Hard

Merkle–Damgård construction

In cryptography, the Merkle–Damgård construction or Merkle–Damgård hash function is a method of building collision-resistant cryptographic hash functions from collision-resistant one-way compression functions. This construction was used in the design of many popular hash algorithms such as MD5, SHA-1, and SHA-2.

Merkle's Puzzles

In cryptography, Merkle's Puzzles is an early construction for a public-key cryptosystem, devised by Ralph Merkle in 1974 and published in 1978. The protocol allows two parties to agree on a shared secret by exchanging messages, even if they share no secret beforehand. The scheme provides a quadratic security gap between legitimate parties and an eavesdropper, and is recognized as a precursor to public-key cryptography in the modern sense.

Message Authenticator Algorithm

The Message Authenticator Algorithm (MAA) was one of the first cryptographic functions for computing a message authentication code (MAC).

A micropayment is essentially a small transaction that is carried out online and can be as small as a fraction of a cent.

Easy

Microsoft Point-to-Point Encryption

Microsoft Point-to-Point Encryption (MPPE) encrypts data in Point-to-Point Protocol (PPP)-based dial-up connections or Point-to-Point Tunneling Protocol (PPTP) virtual private network (VPN) connections. 128-bit key (strong), 56-bit key, and 40-bit key (standard) MPPE encryption schemes are supported. MPPE provides data security for the PPTP connection that is between the VPN client and the VPN server.

Microsoft Points

Microsoft Points, introduced in November 2005 as Xbox Live Points, were a digital currency issued by Microsoft for use on its Xbox and Zune product lines. Points could be used to purchase video games and downloadable content from Xbox Live Marketplace, digital content such as music and videos on Zune Marketplace, along with content from Windows Live Gallery.

Microsoft Security Development Lifecycle

The Microsoft Security Development Lifecycle (SDL) is the approach Microsoft uses to integrate security into DevOps processes (sometimes called a DevSecOps approach). You can use this SDL guidance and documentation to adapt this approach and practices to your organization.

MicroStrategy

Strategy Inc., formerly known as MicroStrategy, is an American company that provides business intelligence (BI) and mobile software. Founded in 1989 by Michael J. Saylor, Sanju Bansal, and Thomas Spahr, the firm develops software to analyze internal and external data in order to make business decisions and to develop mobile apps. It is a public company headquartered in Tysons Corner, Virginia, in the Washington metropolitan area. Its primary business analytics competitors include SAP SE Business Objects, IBM Cognos, and Oracle Corporation's BI Platform. Saylor is the executive chairman and, from 1989 to 2022, was the CEO.

Microtransaction

A business model where very small payments can be made in exchange for common digital goods and services, such as pages of an ebook or items in a game.

Moderate

Mid Cap

Mid cap is a measure derived from a mathematical computation that determines the market value of a cryptocurrency with a market capitalization ranging from $1 billion to $10 billion.

Easy

Mihaela Ulieru

Mihaela Ulieru is a Romanian-Canadian computer scientist and systems researcher whose work focuses on distributed intelligence, adaptive systems, artificial intelligence, and decentralized socio-technical systems. Her research has examined the intersection of complex systems, digital governance, and emerging technologies, including blockchain and collective intelligence.

MIKEY

Multimedia Internet KEYing (MIKEY) is a key management protocol that is intended for use with real-time applications. It can specifically be used to set up encryption keys for multimedia sessions that are secured using SRTP, the security protocol commonly used for securing real-time communications such as VoIP.

MilliBitcoin

MilliBitcoin, also known as mBTC, is a sub-unit of Bitcoin which is equivalent to the one-thousandth of a BTC, the most famous and valuable cryptocurrency in the world.

Moderate

MintChip is a digital currency that provides the underlying system to facilitate the exchange of value between consumers and merchants in real-time. It was designed to reduce the cost and risk of financial transactions. This technology was created by the Royal Canadian Mint, backed by the Government of Canada and denominated in a variety of fiat currencies. The Royal Canadian Mint announced the MintChip project in 2012 and simultaneously launched the MintChip Challenge contest to encourage development of interesting uses for the MintChip. In January 2016, Loyalty Pays Holdings corporation—a wholly owned subsidiary of nanoPay, a fully integrated loyalty and payments platform provider, announced the acquisition of all assets related to MintChip.

Minting

Minting is the process of generating new coins using the proof-of-stake mechanism and adding them to the circulation to be traded.

Easy

Mix network

Mix networks are routing protocols that create hard-to-trace communications by using a chain of proxy servers known as mixes which take in messages from multiple senders, shuffle them, and send them back out in random order to the next destination. This breaks the link between the source of the request and the destination, making it harder for eavesdroppers to trace end-to-end communications. Furthermore, mixes only know the node that it immediately received the message from, and the immediate destination to send the shuffled messages to, making the network resistant to malicious mix nodes.

Mnemonic Phrase

A list of words used in sequence to access or restore your crypto assets.

Easy

Mnemonics

Mnemonics are memory aids with a system such as letters or associations that help in recall. *see Mnemonic Phrase.

Easy

Mobile Wallet

A mobile wallet is a crypto wallet installed on a mobile device.

Easy

MobileCoin

MobileCoin, also known as Sentz, is a peer-to-peer cryptocurrency developed by MobileCoin Inc., which was founded in 2017 by Josh Goldbard and Shane Glynn.

Modular Proof Verification

Modular proof verification is a process where confirming the validity and correctness of a ZK Proof, one of the most expensive parts of running ZK rollups and ZK apps, is offloaded to a dedicated service.

Hard

Moloch DAO

Moloch DAO can refer to the DAO framework, a description of a DAO that uses the framework, or the name of the Ethereum grant-giving DAO that originally created the framework.

Moderate

Music cipher

In cryptography, a music cipher is an algorithm for the encryption of a plaintext into musical symbols or sounds. Music-based ciphers are related to, but not the same as musical cryptograms. The latter were systems used by composers to create musical themes or motifs to represent names based on similarities between letters of the alphabet and musical note names, such as the BACH motif, whereas music ciphers were systems typically used by cryptographers to hide or encode messages for reasons of secrecy or espionage.

Musical cryptogram

A musical cryptogram is a cryptogrammatic sequence of musical symbols which can be taken to refer to an extra-musical text by some 'logical' relationship, usually between note names and letters. The most common and best known examples result from composers using musically translated versions of their own or their friends' names as themes or motifs in their compositions, with an early and commonly known example being the BACH sequence used by the composer. These are not really rigorous cipher algorithms in the formal sense, but more like musical monograms or labels using initials. The methods used historically by composers were either too incomplete or too simplistic to meaningfully encrypt long text messages. There is a separate history of music ciphers utilizing music notation to encode messages for reasons of espionage or personal security that involved encryption and/or steganography.

MuSig2

A Schnorr-based multisig protocol that aggregates several signatures into a single 64-byte signature indistinguishable from a single-signer transaction. Lower on-chain cost and better privacy than script-based multisig, at the price of an interactive signing round between cosigners. Not used in SSP's default 2-of-2 flow today (which uses P2WSH/script-based multisig), but a candidate for future Taproot-based variants.

Advanced

Mutual Credit Line

Mutual credit is a multilateral exchange network in which money created endogenously within the network serves as a medium of exchange.

Hard

My Story (VeChain)

A digital assurance system built on a blockchain by DNV and VeChain.

Moderate

N

N-hash

In cryptography, N-hash is a cryptographic hash function based on the FEAL round function, and is now considered insecure. It was proposed in 1990 in an article by Miyaguchi, Ohta, and Iwata; weaknesses were published the following year.

Name Wrapper

Name Wrapper is a smart contract that allows all registered ENS names to be converted into NFTs, expanding their customizability.

Moderate

Namecoin

Namecoin is a cryptocurrency originally forked from bitcoin software. It uses proof-of-work algorithm. Like bitcoin, it is limited to 21 million coins.

Nano (cryptocurrency)

Nano is a cryptocurrency characterized by a directed acyclic graph data structure and distributed ledger, making it possible for Nano to work without intermediaries. To agree on what transactions to commit, it uses a voting system with weight based on the amount of currency an account holds.

Naor–Reingold pseudorandom function

In 1997, Moni Naor and Omer Reingold described efficient constructions for various cryptographic primitives in private key as well as public-key cryptography. Their result is the construction of an efficient pseudorandom function. Let p and l be prime numbers with l |p−1. Select an element g ∈ of multiplicative order l. Then for each (n+1)-dimensional vector a = (a0,a1, ..., an)∈ they define the function

NEAR (blockchain platform)

NEAR is a public blockchain platform that uses a proof-of-stake consensus mechanism and provides smart-contract functionality. Its native cryptocurrency is NEAR. It was founded in 2018 by Illia Polosukhin and Alexander Skidanov, with mainnet launching in 2020.

Negative Volume Index (NVI)

The negative volume index (NVI) is a powerful technical indicator that shows how price is being influenced by low-volume timeframes.

Hard

NEO (blockchain)

Neo is a blockchain-based cryptocurrency and application platform used to run smart contracts and decentralized applications. The project, originally named Antshares, was founded in 2014 by Da HongFei and Erik Zhang and rebranded as Neo in 2017. In 2017 and 2018, it became popular in China despite the recently enacted prohibition on cryptocurrency in that country.

Nervos Network

Nervos Network is a proof-of-work blockchain platform which consists of multiple blockchain layers that are designed for different functions. The native cryptocurrency of this layer is called CKB. Smart contracts and decentralized applications can be deployed on the Nervos blockchain. The Nervos Network was founded in 2018.

Neteller

Neteller is a global payments platform and digital wallet used to transfer money to and from merchants, such as forex trading brokers, social networks, and gambling websites. Users in the European Economic Area (EEA) and the United Kingdom can add a Net+ Mastercard to their account to pay with their balance in stores or withdraw it as cash from ATMs. Regardless of their location, users can transfer their balance to their own bank accounts or cards if they need to withdraw the funds from their account.

Network

A network refers to all nodes in the operation of a blockchain at any given moment in time.

Moderate

Network Latency

Network latency refers to the amount of time it takes for a computer on one network to communicate with a computer on another network.

Easy

Network-Enhanced Virtual Machine (NEVM)

A Network-Enhanced Virtual Machine (NEVM) combines the best attributes of the Bitcoin (BTC) and Ethereum (ETH) networks, enabling smart contracts to leverage unprecedented levels of interoperability and scalability to support broad mass adoption.

Hard

Nick Szabo

Nick Szabo is the inventor of Bit Gold and the use of smart contracts.

Easy

Nifty Gateway

Nifty Gateway is an NFT platform owned by the Winklevoss twins.

Easy

NIPRNet

The Non-classified Internet Protocol (IP) Router Network (NIPRNet) is an IP network used to exchange unclassified information, including information subject to controls on distribution, among the private network's users. The NIPRNet also provides its users access to the Internet.

NIST hash function competition

The NIST hash function competition was an open competition held by the US National Institute of Standards and Technology (NIST) to develop a new hash function called SHA-3 to complement the older SHA-1 and SHA-2. The competition was formally announced in the Federal Register on November 2, 2007. "NIST is initiating an effort to develop one or more additional hash algorithms through a public competition, similar to the development process for the Advanced Encryption Standard (AES)." The competition ended on October 2, 2012, when NIST announced that Keccak would be the new SHA-3 hash algorithm.

No-Coiner

A no-coiner is someone who has no cryptocurrency in his or her investment portfolio and firmly believes that cryptocurrency in general will fail.

Easy

Node

The most basic unit of blockchain infrastructure that stores data.

The term "non-fungible assets" describes non-fungibility within a collection of similar assets being issued by a single party.

Moderate

Non-Fungible Token (NFT)

Non-fungible tokens (NFTs) are cryptocurrencies that do not possess the property of fungibility.

Easy

Non-interactive zero-knowledge proof

Non-interactive zero-knowledge proofs are cryptographic primitives, where information between a prover and a verifier can be authenticated by the prover, without revealing any of the specific information beyond the validity of the statement itself. This makes direct communication between the prover and verifier unnecessary, effectively removing any intermediaries.

Non-physical true random number generator

A non-physical true random number generator (NPTRNG), also known as a non-physical nondeterministic random bit generator, is a generator of unpredictable random numbers without the use of a dedicated hardware entropy source. An NPTRNG uses a non-physical noise source that obtains entropy from system data, such as outputs of application programming interface functions, residual information in random access memory, system time, or human input, in the expectation that that data may contain elements that are truly random or at least not known to or controllable by an adversary. A typical NPTRNG is implemented as software running on a general-purpose computer. NPTRNGs are found in the kernels of popular operating systems that are expected to run on any generic CPU without requiring specialised hardware.

Non-repudiation

In law, non-repudiation is a situation where a statement's author cannot successfully dispute its authorship or the validity of an associated contract. The term is often seen in a legal setting when the authenticity of a signature is being challenged. In such an instance, the authenticity is being "repudiated".

Nonce

In Ethereum, a per-account counter that increments with each transaction sent from that account. The nonce ensures transactions are processed in order and prevents replay attacks: a transaction with a nonce that has already been used will be rejected. If you send a transaction with nonce 5 while nonce 4 is still pending, the nonce-5 transaction will be stuck until nonce 4 confirms.

Moderate

Nonce (Bitcoin)

A 32-bit field in the Bitcoin block header that miners increment to change the block hash during proof-of-work mining. Unlike the Ethereum account nonce (which counts transactions), the Bitcoin nonce has no transaction-ordering role — it simply gives miners a variable to iterate over when searching for a hash below the difficulty target. When the 32-bit space is exhausted, miners also vary the extra nonce in the coinbase transaction.

Advanced

Nonce Error

A nonce error occurs when a nonce - a number used only once - is misused or mishandled in a system.

Hard

Normal basis

In mathematics, specifically the algebraic theory of fields, a normal basis is a special kind of basis for Galois extensions of finite degree, characterised as forming a single orbit for the Galois group. The normal basis theorem states that any finite Galois extension of fields has a normal basis. In algebraic number theory, the study of the more refined question of the existence of a normal integral basis is part of Galois module theory.

Nostr

Nostr is an open protocol for decentralized message transmission, with the intention to be able to resist internet censorship while maintaining session integrity. "Noster" can also be translated as "our" or "ours" from Latin. The protocol achieves decentralization through users publishing content associated with a cryptographic public key to various "relays", which are WebSocket servers that store and distribute an activity stream of received data from users. This allows the network to verify users and achieve account portability on Nostr, as users have to sign all posts using their secret key, preventing any relay from tampering with content without invalidating the signature.

Notarization on Blockchain

Notarization on blockchain simply uses the intrinsic nature and advantages of blockchain technology to let anyone create a timestamped artifact. The authorship and identity of this artifact can easily and securely be identified at any point.

Hard

Nothing-up-my-sleeve number

In cryptography, nothing-up-my-sleeve numbers are any numbers which, by their construction, are above suspicion of hidden properties. They are used in creating cryptographic functions such as hashes and ciphers. These algorithms often need randomized constants for mixing or initialization purposes. The cryptographer may wish to pick these values in a way that demonstrates the constants were not selected for a nefarious purpose, for example, to create a backdoor to the algorithm. These fears can be allayed by using numbers created in a way that leaves little room for adjustment. An example would be the use of initial digits from the number π as the constants. Using digits of π millions of places after the decimal point would not be considered trustworthy because the algorithm designer might have selected that starting point because it created a secret weakness the designer could later exploit—though even with natural-seeming selections, enough entropy exists in the possible choices that the utility of these numbers has been questioned.

Numerai

Numerai is an AI-run, crowd-sourced hedge fund based in San Francisco. It was founded by South African technologist Richard Craib in October 2015.

Nxt

NXT is an open source cryptocurrency and payment network launched in 2013 by anonymous software developer BCNext. It uses proof-of-stake to reach consensus for transactions—as such, there is a static money supply. Unlike Bitcoin, there is no mining.

O

Oak Industries

Oak Industries, Inc. was an American electronics company that manufactured a variety of products throughout seven decades in the 20th century. In existence from 1932 to 2000, the company's business lines primarily centered around electronic components and materials, though the company made a high-profile and ultimately failed extension into communications media in the late 1970s and early 1980s. The firm was founded in Crystal Lake, Illinois, moving its headquarters to Rancho Bernardo, California, in the late 1970s and again to Waltham, Massachusetts, in 1990. Corning Inc. purchased Oak in January 2000 primarily for its Lasertron division, a manufacturer of lasers.

Oakley protocol

The Oakley Key Determination Protocol is a key-agreement protocol that allows authenticated parties to exchange keying material across an insecure connection using the Diffie–Hellman key exchange algorithm. The protocol was proposed by Hilarie K. Orman in 1998, and formed the basis for the more widely used Internet Key Exchange protocol.

Oblivious HTTP

Oblivious HTTP (OHTTP) is an IETF network protocol intended to enable anonymous HTTP transactions over the Internet. Its goal is to allow a user to send an HTTP request to a web server without allowing any single entity to see both the content of the request and the sender's IP address, since the IP address could be connected to the identity of the sender. OHTTP is documented in RFC 9458, published in January 2024 by authors affiliated with Mozilla and Cloudflare. The RFC says "Oblivious HTTP is simpler and less costly than more robust systems, like Prio or Tor, which can provide stronger guarantees at higher operational costs."

Oblivious pseudorandom function

An oblivious pseudorandom function (OPRF) is a cryptographic function, similar to a keyed-hash function, but with the distinction that in an OPRF two parties cooperate to securely compute a pseudorandom function (PRF).

Oblivious transfer

In cryptography, an oblivious transfer (OT) protocol is a type of protocol in which a sender transfers one of potentially many pieces of information to a receiver, but remains oblivious as to what piece has been transferred.

Off-the-Record Messaging (OTR) is a cryptographic protocol that provides encryption for instant messaging conversations. OTR uses a combination of AES symmetric-key algorithm with 128 bits key length, the Diffie–Hellman key exchange with 1536 bits group size, and the SHA-1 hash function. In addition to authentication and encryption, OTR provides forward secrecy and malleable encryption.

Offensive Security

Offensive Security is an American international company working in information security, penetration testing and digital forensics. Beginning around 2007, the company created open source projects, advanced security courses, the ExploitDB vulnerability database, and the Kali Linux distribution. OffSec was started by Mati Aharoni, and employs security professionals with experience in security penetration testing and system security evaluation. The company has provided security counseling and training to many technology companies.

Office of the Comptroller of the Currency (OCC)

The Office of the Comptroller (OCC) is a U.S. Treasury branch that regulates all national banks, federal savings associations, federal branches and foreign bank agencies

Easy

Offline private key protocol

The Offline Private Key Protocol (OPKP) is a cryptographic protocol to prevent unauthorized access to back up or archive data. The protocol results in a public key that can be used to encrypt data and an offline private key that can later be used to decrypt that data.

Offline root certificate authority

An offline root certificate authority is a certification authority which has been isolated from network access, and is often kept in a powered-down state.

Offline Storage

The act of storing cryptocurrencies in devices or systems not connected to the internet.

Moderate

Offshore Account

An offshore account is defined as a foreign bank account with assets and investments set outside of your origin country or country of residence.

Easy

OHM Fork

OlympusDAO or Ohm Forks represent the upgrades to OlympusDAO’s codebase that has given birth to a variety of forked products.

Moderate

OKX

OKX, formerly known as OKEx, is a cryptocurrency exchange and blockchain services company headquartered in San Jose, California. The platform offers trading in digital assets, as well as services including decentralized finance (DeFi) access through its OKX Wallet. The company was founded by Star Xu and rebranded from OKEx to OKX in 2022.

Olympics Go! Paris 2024

Olympics Go! Paris 2024 is a 2024 city-building and sports video game published by nWay and officially licensed with the International Olympic Committee (IOC) to coincide with the 2024 Summer Olympics.

OMEMO

OMEMO is an extension to the Extensible Messaging and Presence Protocol (XMPP) for multi-client end-to-end encryption developed by Andreas Straub. According to Straub, OMEMO uses the Double Ratchet Algorithm "to provide multi-end to multi-end encryption, allowing messages to be synchronized securely across multiple clients, even if some of them are offline". The name "OMEMO" is a recursive acronym for "OMEMO Multi-End Message and Object Encryption". It is an open standard based on the Double Ratchet Algorithm and the Personal Eventing Protocol . OMEMO offers future and forward secrecy and deniability with message synchronization and offline delivery.

Omnichain

Omnichain refers to a blockchain infrastructure that leverages chain abstraction to facilitate seamless interaction, data transfer, and transaction settlement across multiple blockchains.

Hard

On-Balance Volume (OBV)

On-balance volume (OBV) is a technical trading indicator that forecasts an asset's price movements based on the volume flow.

Easy

On-Chain

Transactions that are recorded on the blockchain itself and shared with all of the participants are done on-chain.

Moderate

On-Chain Governance

On-chain governance is a decentralized framework used for organizing and integrating updates/improvements to the blockchain networks.

Moderate

On-Ledger Currency

A currency that is both minted on the blockchain ledger and also used on the blockchain ledger, such as Bitcoin.

Moderate

Onchain Fiat

Onchain fiat is a first-of-its-kind, fully authorized and regulated subset of stablecoins that allows for seamless transitions between traditional bank accounts and web3.

Easy

One Cancels the Other Order (OCO)

A situation where two orders for cryptocurrency are placed simultaneously, with a rule in place to enforce that if one is accepted, the other is cancelled.

Easy

One-time pad

The one-time pad (OTP) is an encryption technique that cannot be cracked in cryptography. It requires the use of a single-use pre-shared key that is larger than or equal to the size of the message being sent. In this technique, a plaintext is paired with a random secret key. Then, each bit or character of the plaintext is encrypted by combining it with the corresponding bit or character from the pad using modular addition.

One-way compression function

In cryptography, a one-way compression function is a function that transforms two fixed-length inputs into a fixed-length output. The transformation is "one-way", meaning that it is difficult given a particular output to compute inputs which compress to that output. One-way compression functions are not related to conventional data compression algorithms, which instead can be inverted exactly or approximately to the original data.

One-way function

In computer science, a one-way function is a function that is easy to compute on every input, but hard to invert given the image of a random input. Here, "easy" and "hard" are to be understood in the sense of computational complexity theory, specifically the theory of polynomial time problems. This has nothing to do with whether the function is one-to-one; finding any one input with the desired image is considered a successful inversion.

OneID

OneID was a digital security service based in Redwood City, California. OneID sold a digital identity system that claimed to provide security across all devices using public-key cryptography instead of passwords. The technology is utilized by non-profits, such as Salsa Labs, to increase the frequency and security of online donations. OneID now operates as a subsidiary program of Neustar following its acquisition in 2016.

Onion routing

Onion routing is a technique for anonymous communication over a computer network. In an onion network, messages are encapsulated in layers of encryption, analogous to the layers of an onion. The encrypted data is transmitted through a series of network nodes called "onion routers," each of which "peels" away a single layer, revealing the data's next destination. When the final layer is decrypted, the message arrives at its destination. The sender remains anonymous because each intermediary knows only the location of the immediately preceding and following nodes. While onion routing provides a high level of security and anonymity, there are methods to break the anonymity of this technique, such as timing analysis.

Online Banking ePayments

Online Banking ePayments (OBeP) is a type of payments network, developed by the banking industry in conjunction with technology providers. It is specifically designed to address the unique requirements of payments made via the Internet.

Online Certificate Status Protocol

The Online Certificate Status Protocol (OCSP) is an Internet protocol used for obtaining the revocation status of an X.509 digital certificate. It was created as an alternative to certificate revocation lists (CRL), specifically addressing certain problems associated with using CRLs in a public key infrastructure (PKI). Messages communicated via OCSP are encoded in ASN.1 and are usually communicated over HTTP. The "request/response" nature of these messages leads to OCSP servers being termed OCSP responders.

Online credentials for learning

Online credentials for learning are digital credentials that are offered in place of traditional paper credentials for a skill or educational achievement. They are directly linked to the accelerated development of internet communication technologies, the development of digital badges, electronic passports and massive open online courses (MOOCs).

Online Storage

The act of storing cryptocurrencies in devices or systems connected to the internet.

Moderate

The price at which a cryptocurrency opens at a time period or the programming principle of software parts being extendable.

Easy

OpenSea

OpenSea is a decentralized P2P platform for NFTs.

Easy

An orphaned block is a block where the parent block does not exist or is unknown.

Moderate

When a cryptocurrency has been sold by more and more investors over time, with its price decreasing for an extended period of time.

Parachain

Parachains are application-specific data structures that run in parallel to each other within Polkadot.

Hard

Participation Node

Participation nodes are present in the Algorand platform to help in conducting the Pure Proof of Stake (PPoS) consensus process.

Hard

Passive Income

Passive income is money produced from investments that do not require the earner to be actively involved.

Easy

Passphrase

An optional extra string — sometimes called the '25th word' — appended to a BIP-39 mnemonic before the seed is derived. A passphrase creates a completely separate wallet from the same seed words, so an attacker who finds the mnemonic still cannot access funds without the passphrase. The passphrase is not stored anywhere and must be memorized or stored separately from the seed words.

Moderate

Password Authenticated Key Exchange by Juggling

The Password Authenticated Key Exchange by Juggling is a password-authenticated key agreement protocol, proposed by Feng Hao and Peter Ryan. This protocol allows two parties to establish private and authenticated communication solely based on their shared (low-entropy) password without requiring a Public Key Infrastructure. It provides mutual authentication to the key exchange, a feature that is lacking in the Diffie–Hellman key exchange protocol.

Password Manager

A password manager is a tool or software that stores all sorts of passwords needed for online applications and services.

Easy

Password strength

Password strength is a measure of the effectiveness of a password against guessing or brute-force attacks. In its usual form, it estimates how many trials an attacker who does not have direct access to the password would need, on average, to guess it correctly. The strength of a password is a function of length, complexity, and unpredictability.

Password-authenticated key agreement

In cryptography, a password-authenticated key agreement (PAK) method is an interactive method for two or more parties to establish cryptographic keys based on one or more parties' knowledge of a password.

Password-based cryptography

Password-based cryptography is the study of password-based key encryption, decryption, and authorization. It generally refers two distinct classes of methods:Single-party methods Multi-party methods

Paul Le Roux

Paul Le Roux is a criminal kingpin that many believe could be the founder of Bitcoin, Satoshi Nakamoto.

Easy

Payee

A payee is a party within an exchange of goods or even services that can receive payment.

Moderate

Paymaster

An ERC-4337 contract that sponsors the gas fees for a UserOperation, allowing the user to pay in ERC-20 tokens or receive completely gasless transactions. Paymasters inspect the UserOperation and agree to reimburse the bundler in ETH if the operation succeeds according to their rules. They are optional; without a paymaster the smart-contract wallet must hold ETH to pay its own gas.

Advanced

Payment Services Directive

The Revised Payment Services Directive (PSD2, Directive (EU) 2015/2366, which replaced the Payment Services Directive (PSD), Directive 2007/64/EC) is an EU Directive, administered by the European Commission (Directorate General Internal Market) to regulate payment services and payment service providers throughout the European Union (EU) and European Economic Area (EEA). The PSD's purpose was to increase pan-European competition and participation in the payments industry also from non-banks, and to provide for a level playing field by harmonizing consumer protection and the rights and obligations of payment providers and users. The key objectives of the PSD2 directive are creating a more integrated European payments market, making payments more secure and protecting consumers.

Payment tokenization

Payment tokenization is a data security process that replaces sensitive payment information, such as credit card numbers, with a unique identifier or "token." This token can be used in place of actual data during transactions but has no exploitable value if breached, thereby reducing the risk of data theft and fraud.

Payments as a service

Payments as a service (PaaS) is a marketing phrase used to describe software as a service to connect a group of international payment systems. The architecture is represented by a layer – or overlay – that resides on top of these disparate systems and provides for two-way communications between the payment system and the PaaS. Communication is governed by standard APIs created by the PaaS provider.

Paysafe

Paysafe Limited is a multinational online payments company. Paysafe offers payment processing, digital wallet and online cash systems to businesses and consumers, with particular experience of serving the global entertainment sectors. The group offers services both under the Paysafe brand and subsidiary brands that have become part of the group through several mergers and acquisitions, most notably Neteller, Skrill, SafetyPay, PagoEfectivo, PaysafeCash and PaysafeCard.

PaysafeCard

PaysafeCard is a prepaid e-commerce payment solution powered by vouchers. It is part of Paysafe, a global payments platform. PaysafeCard allows customers to pay online without providing personal financial information.

Peer-to-Peer (P2P)

The decentralized interactions between parties in a distributed network, partitioning tasks or workloads between peers.

Easy

Peer-to-Peer (P2P) Lending

Crypto P2P lending refers to a practice of lending assets without the involvement of a middleman. Such loans rely on collateral material originally owned by borrowers.

Easy

Peercoin

Peercoin, also known as Peer-to-Peer Coin, PP Coin, or PPC, is a cryptocurrency utilizing both proof-of-stake and proof-of-work systems. It is notable as the first cryptocurrency to implement the proof-of-stake consensus mechanism.

Peg

A “peg” is a specified price for the rate of exchange between two assets.

Easy

Pegged Currency

A stablecoin is a currency whose value is pegged to a real-world asset, such as a fiat currency.

Moderate

Pepe the Frog

Pepe the Frog is a comic character and Internet meme created by cartoonist Matt Furie. Designed as a green anthropomorphic frog with a humanoid body usually wearing a blue t-shirt, Pepe originated in Furie's 2005 webcomic Boy's Club. The character became an Internet meme when his popularity steadily grew across websites such as Myspace, Gaia Online, and 4chan from 2008 onwards; by 2015, he had become one of the most popular memes on 4chan and Tumblr.

The petro (₽), or petromoneda, launched in February 2018, was a crypto token issued by the government of Venezuela.

PGP word list

The PGP Word List is a list of words for conveying data bytes in a clear unambiguous way via a voice channel. They are analogous in purpose to the NATO phonetic alphabet, except that a longer list of words is used, each word corresponding to one of the 256 distinct numeric byte values.

Philco computers

Philco was one of the pioneers of transistorized computers, also known as second-generation computers. After the company developed the surface-barrier transistor, which was much faster than previous point-contact types, it was awarded contracts for military and government computers. Commercialized derivatives of some of these designs became successful business and scientific computers. The TRANSAC Model S-1000 was released as a scientific computer. The TRANSAC S-2000 mainframe computer system was first produced in 1958, and a family of compatible machines, with increasing performance, was released over the next several years.

Phishing

A social-engineering attack that tricks users into visiting a fraudulent website or app that mimics a legitimate one, then harvests seed phrases, private keys, or wallet signatures. Crypto phishing pages often rank in search results or arrive via direct messages on social platforms. SSP's two-device model does not protect against a user who voluntarily enters their seed phrase into a fake site.

Beginner

Phone Phishing

Phone phishing, also known as a telephone scam or vishing (voice phishing), refers to the practice of using fraudulent and malicious phone calls to extort money or sensitive information from victims.

Easy

Physical Bitcoins

A physical Bitcoin is a physical token that usually has an intricate design, as well as a public key and private key.

Easy

Physical unclonable function

A physical unclonable function, or PUF, is a physical object whose operation cannot be reproduced ("cloned") in physical way, that for a given input and conditions (challenge), provides a physically defined "digital fingerprint" output (response) that serves as a unique identifier, most often for a semiconductor device such as a microprocessor or a material producing an optical signal. PUFs are often based on unique physical variations occurring naturally during semiconductor manufacturing. A PUF is a physical entity embodied in a physical structure. PUFs can be implemented in integrated circuits, including FPGAs, and can be used in applications with high-security requirements, more specifically cryptography, Internet of things (IOT) devices and privacy protection. PUFs can also be physical materials which provide uniqueness of distribution that can be used for authentication. The term is also commonly expanded as a physically unclonable function in the academic literature.

A numeric or alphanumeric code that unlocks a wallet app or hardware device without requiring the full seed phrase. PINs protect against casual physical access but are not a substitute for seed backup — if the device is wiped or lost, the PIN is useless without the seed. SSP apps use a PIN or biometric unlock for daily use; the seed phrase is the ultimate recovery mechanism.

Beginner

Pineapple Fund

The Pineapple Fund was a philanthropic project by an anonymous individual which gave away 5,057 bitcoins to 60 charities. The amount was valued at $86 million in December 2017. Some of the themes supported were medical research, environmental conservation, human rights and psychedelic therapy.

Pingping (payment)

Pingping is an electronic micropayment system available in Belgium which allows users to make cashless purchases via a near-field communication (NFC) card or a using text messaging on a mobile phone. PingPing was founded by the Belgian telecom operator Belgacom in March 2009 and the technology was developed by Tunz, a mobile payments specialist which Belgacom acquired a 40% stake in PingPing. The system was subsequently acquired by Alfa-Zet Systems, a cashless payment specialist in Belgium and Holland.

Pizzino

Pizzino is an Italian language word derived from the Sicilian language equivalent pizzinu meaning "small piece of paper". The word has been widely used to refer to small slips of paper that the Sicilian Mafia uses for high-level communications.

PKCS

Public Key Cryptography Standards (PKCS) are a group of public-key cryptography intervendor standards first developed by RSA Security, with involvement from Apple, Digital, Lotus Development, Microsoft, MIT, Northern Telecom, and Sun Microsystems, first published in June 1991.

Plaintext

In cryptography, plaintext usually means unencrypted information pending input into cryptographic algorithms, usually encryption algorithms. This usually refers to data that is transmitted or stored unencrypted.

Platform

On CoinMarketCap, platform refers to the parent blockchain of tokens. It may also refer to a cryptocurrency exchange on which you may trade cryptocurrencies.

Easy

Play-to-Earn (Play2Earn)

The play-to-earn business model supports the notion of an open economy and gives financial rewards to players who bring value to its metaverse.

Easy

Play2Earn (Play-to-Earn)

The play-to-earn business model supports the notion of an open economy and gives financial rewards to players who bring value to its metaverse.

Easy

Player Payout

Player payouts is a new way of automatically paying online gaming participants immediately after the tournament ends.

Moderate

PlayNow Arena

PlayNow was Sony Ericsson's download service for media that included music, games, ringtones, wallpapers and themes. It was introduced in February 2004 as a way for owners of SE phones to listen to and directly purchase ringtones. It was rolled out into 32 countries. The Sony Ericsson S700 was the first Sony Ericsson phone to come pre-loaded with PlayNow.

Plutus (Cardano)

The scripting language used on Cardano blockchain for smart contract development.

Hard

Point-to-point encryption

Point-to-point encryption (P2PE) is a standard established by the PCI Security Standards Council. Payment solutions that offer similar encryption but do not meet the P2PE standard are referred to as end-to-end encryption (E2EE) solutions. The objective of P2PE and E2EE is to provide a payment security solution that instantaneously converts confidential payment card data and information into indecipherable code at the time the card is swiped, in order to prevent hacking and fraud. It is designed to maximize the security of payment card transactions in an increasingly complex regulatory environment.

Pointcheval–Stern signature algorithm

In cryptography, the Pointcheval–Stern signature algorithm is a digital signature scheme based on the closely related ElGamal signature scheme. It changes the ElGamal scheme slightly to produce an algorithm which has been proven secure in a strong sense against adaptive chosen-message attacks, assuming the discrete logarithm problem is intractable in a strong sense.

Politeia (Decred)

A decentralized governance platform that allows Decred stakeholders to submit, track and discuss proposals for suggestion and implementation of new ideas.

Moderate

Polkadot (blockchain platform)

Polkadot is a decentralized, nominated proof-of-stake blockchain with smart contract functionality. The cryptocurrency native to the blockchain is the DOT.

Polygon (blockchain)

Polygon is a blockchain platform which aims to create a multi-chain blockchain system compatible with Ethereum. As with Ethereum, it uses a proof-of-stake consensus mechanism for processing transactions on-chain. Polygon's native token is POL, an ERC-20 token which allows for compatibility with other Ethereum cryptocurrencies. It is operated by Polygon Labs.

Polygraphic substitution

Polygraphic substitution is a substitution cipher in which a uniform substitution is performed on blocks of letters. When the length of the block is specifically known, more precise terms are used: for instance, a cipher in which pairs of letters are substituted is bigraphic.

Polymarket

Polymarket is an American cryptocurrency-based prediction market which offers a platform where individuals can place bets on future outcomes, including sports matches, economic indicators, weather patterns, awards, political and legislative outcomes, and military conflicts. Participants can deposit USDC cryptocurrency through the Polygon blockchain network and trade shares that represent the likelihood of specific future outcomes. The company is headquartered in Manhattan, New York City, where the platform was launched in 2020.

Ponzi Scheme

A fraudulent investment involving the payment of purported returns to existing investors from funds contributed by new investors.

Easy

POODLE

POODLE is a security vulnerability which takes advantage of the fallback to SSL 3.0. If attackers successfully exploit this vulnerability, on average, they only need to make 256 SSL 3.0 requests to reveal one byte of encrypted messages. Bodo Möller, Thai Duong and Krzysztof Kotowicz from the Google Security Team discovered this vulnerability; they disclosed the vulnerability publicly on October 14, 2014. On December 8, 2014, a variation of the POODLE vulnerability that affected TLS was announced.

Poolsuite

Poolsuite, formerly Poolside.FM, is an Internet radio service primarily playing dance-pop music using a retro style user interface. The team behind Poolsuite has also launched Vacation, a line of sunscreen, and Manor DAO, a decentralized autonomous organization funded through sales of non-fungible tokens (NFT).

Portfolio

A collection of cryptocurrencies or crypto assets held by an investment company, hedge fund, financial institution or individual.

Easy

Portfolio Tracking

The act of tracking the movement and performance of assets of your financial holdings is termed portfolio tracking. This monitoring activity can cover stocks, commodities, mutual funds, ETFs, cryptocurrencies and NFTs

Moderate

Position Size

Position size is a vital part of a trading strategy, since it is directly related to one’s potential profit or loss. Sizing a position also plays an important role in risk management as knowing when to execute larger or smaller trades, and when to increase or reduce the size of a position impacts profitability.

Moderate

Post-Mine

The retroactive creation of new coins following a cryptocurrency’s launch, before public mining is possible.

Moderate

Post-quantum cryptography

Post-quantum cryptography (PQC), sometimes referred to as quantum-proof, quantum-safe, or quantum-resistant, is the development of cryptographic algorithms that are currently thought, but not proven, to be secure against a cryptanalytic attack by a quantum computer. Most widely used public-key algorithms rely on the difficulty of one of three mathematical problems: the integer factorization problem, the discrete logarithm problem, or the elliptic-curve discrete logarithm problem. All of these problems could be easily solved on a sufficiently powerful quantum computer running Shor's algorithm or possibly alternatives.

Post-Quantum Extended Diffie–Hellman

In cryptography, Post-Quantum Extended Diffie–Hellman (PQXDH) is a Kyber-based post-quantum key exchange method based on Diffie–Hellman key exchange. It has been a key part of the Signal Protocol, a popular end-to-end encryption protocol, since 2023.

Pre-IDO

Pre-IDO refers to token offerings before the actual initial DEX offering (IDO) takes place.

Moderate

Pre-Mine

When some or all of a coin’s initial supply is generated during or before the public launch.

Moderate

Pre-Sale

The sale of a cryptocurrency, ahead of it going public, to specific investors.

Moderate

Prediction Market

Prediction Markets are exchange-traded markets where the future outcomes of events are traded. It indicates the confidence of the crowd in a specific future event.

Moderate

PRESENT

PRESENT is a lightweight block cipher, developed by Orange Labs (France), Ruhr University Bochum (Germany) and the Technical University of Denmark in 2007. PRESENT was designed by Andrey Bogdanov, Lars R. Knudsen, Gregor Leander, Christof Paar, Axel Poschmann, Matthew J. B. Robshaw, Yannick Seurin, and C. Vikkelsoe. The algorithm is notable for its compact size.

Price Impact

The difference between market price and estimated price due to trade size.

Moderate

Pride Icons

Pride Icons is a NFT collection created by Israeli art director Max Bahman in Miami in June 2022 for Pride Month. This NFT project claims to be the world's largest collection of LGBTQ-inspired NFTs.

Primecoin

Primecoin is a cryptocurrency that implements a proof-of-work system that searches for chains of prime numbers.

Prince (cipher)

Prince is a block cipher targeting low latency, unrolled hardware implementations. It is based on the so-called FX construction. Its most notable feature is the alpha reflection: the decryption is the encryption with a related key which is very cheap to compute. Unlike most other "lightweight" ciphers, it has a small number of rounds and the layers constituting a round have low logic depth. As a result, fully unrolled implementation are able to reach much higher frequencies than AES or PRESENT. According to the authors, for the same time constraints and technologies, PRINCE uses 6–7 times less area than PRESENT-80 and 14–15 times less area than AES-128.

Priority Fee

The optional tip paid directly to the block proposer on Ethereum, on top of the burned base fee, to incentivize faster transaction inclusion. Also called the miner tip (EIP-1559 terminology: maxPriorityFeePerGas). During low congestion the priority fee can be near zero; during NFT drops or arbitrage races it can spike to many gwei. Wallets typically suggest priority fees based on recent block history.

Moderate

Privacy-Enhanced Mail

Privacy-enhanced mail (PEM) is a de facto file format for storing and sending cryptographic keys, certificates, and other data, based on a set of 1993 IETF standards defining "privacy-enhanced mail". While the original standards were never broadly adopted and were supplanted by PGP and S/MIME, the textual encoding they defined became very popular. The PEM format was eventually formalized by the IETF in RFC 7468.

Private Blockchain

A private blockchain is a type of blockchain in which only a single organization has authority over the network.

Moderate

Private Communications Technology

Private Communications Technology (PCT) 1.0 was a protocol developed by Microsoft in the mid-1990s. PCT was designed to address security flaws in version 2.0 of Netscape's Secure Sockets Layer protocol and to force Netscape to hand control of the then-proprietary SSL protocol to an open standards body.

Private information retrieval

In cryptography, a private information retrieval (PIR) protocol is a protocol that allows a user to retrieve an item from a server in possession of a database without revealing which item is retrieved. PIR is a weaker version of 1-out-of-n oblivious transfer, where it is also required that the user should not get information about other database items.

Private Key

A 256-bit random integer that is the ultimate proof of ownership for a blockchain address. Anyone who possesses the private key can sign transactions spending from the corresponding address. Private keys must never leave a secure environment — SSP keeps each device's private key confined to that device and never transmits it, even encrypted, through the relay.

Beginner

Private Key/Secret Key

A piece of code generated in asymmetric-key encryption process, paired with a public key, to be used in decrypting information hashed with the public key.

Easy

Private set intersection

Private set intersection is a secure multiparty computation cryptographic technique that allows two parties holding sets to compare encrypted versions of these sets in order to compute the intersection. In this scenario, neither party reveals anything to the counterparty except for the elements in the intersection.

PrivateCore

PrivateCore is a venture-backed startup located in Palo Alto, California that develops software to secure server data through server attestation and memory encryption. The company's attestation and memory encryption technology fills a gap that exists between “data in motion” encryption and “data at rest” encryption by protecting “data in use”. PrivateCore memory encryption technology protects against threats to servers such as cold boot attacks, hardware advanced persistent threats, rootkits/bootkits, computer hardware supply chain attacks, and physical threats to servers from insiders. PrivateCore was acquired by Facebook on 7 August 2014.

Privilege Management Infrastructure

In cryptography Privilege Management is the process of managing user authorisations based on the ITU-T Recommendation X.509. The 2001 edition of X.509 specifies most of the components of a Privilege Management Infrastructure (PMI), based on X.509 attribute certificates (ACs). Later editions of X.509 have added further components to the PMI, including a delegation service and interdomain authorisation.

Probabilistic signature scheme

Probabilistic Signature Scheme (PSS) is a cryptographic signature scheme designed by Mihir Bellare and Phillip Rogaway.

Procedural Programming

Procedural programming refers to a series of instructions that inform a computer what it should do step-by-step to achieve the task.

Hard

Profit and Loss (P&L) Statement

A profit and loss (P&L) statement is a financial document that gives that sum up the earnings, costs, and expenditures incurred during a specified period.

Easy

Programmability

Programmability implies that something is capable of following instructions.

Moderate

Programmable Privacy

Programmable privacy redefines data protection in decentralized applications (dApps), offering a flexible concept that empowers users and developers to personalize privacy settings.

Easy

Proof Market

A proof market is a decentralized marketplace where users can buy and sell cryptographic proofs to verify ownership, the validity of a particular transaction and the authenticity of a piece of information or computation results.

Moderate

Proof of Attendance Protocol

Proof of Attendance Protocol (POAP) refers to a business offering to use the ERC-721 NFT protocol on Ethereum to ascribe individuals a unique, non-fungible blockchain-based identifier that only the person can access

Hard

Proof of authority

Proof of authority (PoA) is a category of consensus protocols used with blockchains based on reputation and identity as a stake that delivers comparatively fast and efficient transactions. The most notable platforms using PoA are VeChain, Bitgert, Palm Network and Xodex.

Proof of identity (blockchain consensus)

Proof of identity (PoID) is a consensus protocol for permission-less blockchains, in which each uniquely identified individual receives one equal unit of voting power and associated rewards. The protocol is based on biometric identification, humanity identification parties and additional verification parties.

Proof of knowledge

In cryptography, a proof of knowledge is an interactive proof in which the prover succeeds in 'convincing' a verifier that the prover knows something. What it means for a machine to 'know something' is defined in terms of computation. A machine 'knows something', if this something can be computed, given the machine as an input. As the program of the prover does not necessarily spit out the knowledge itself, a machine with a different program, called the knowledge extractor is introduced to capture this idea. We are mostly interested in what can be proven by polynomial time bounded machines. In this case, the set of knowledge elements is limited to a set of witnesses of some language in NP.

PANA is an IP-based protocol that allows a device to authenticate itself with a network to be granted access. PANA will not define any new authentication protocol, key distribution, key agreement or key derivation protocols. For these purposes, the Extensible Authentication Protocol (EAP) will be used, and PANA will carry the EAP payload. PANA allows dynamic service provider selection, supports various authentication methods, is suitable for roaming users, and is independent from the link layer mechanisms.

Protocol Layer

A protocol layer of the blockchain is defined as the rules and processes that govern how the network will operate. This is where we can find the different algorithms that determine how consensus is achieved and who gets to create new blocks.

Moderate

Proxy re-encryption

Proxy re-encryption (PRE) schemes are cryptosystems which allow third parties (proxies) to alter a ciphertext which has been encrypted for one party, so that it may be decrypted by another.

PSBT

Partially Signed Bitcoin Transaction — the BIP-174 format for passing a half-built transaction between signers. SSP uses PSBTs internally: SSP Wallet builds and signs first, then ships the PSBT through the encrypted relay to SSP Key for the second signature. Once both signatures are attached, the transaction broadcasts.

Moderate

PSBT Coordination

The end-to-end workflow of constructing, partially signing, relaying, and completing a PSBT across SSP's two devices. SSP Wallet initiates the PSBT by selecting UTXOs, attaching its signature, and encrypting the payload for relay; SSP Key decrypts, verifies the outputs, applies the second signature, and returns the finalized transaction. The coordination layer ensures neither device ever holds a complete transaction until both have reviewed it.

Moderate

Pseudonymous

Writing under a false name, such as “Satoshi Nakamoto.”

Easy

Pseudorandom ensemble

In cryptography, a pseudorandom ensemble is a family of variables meeting the following criteria:

Pseudorandom function family

In cryptography, a pseudorandom function family, abbreviated PRF, is a collection of efficiently-computable functions which emulate a random oracle in the following way: no efficient algorithm can distinguish between a function chosen randomly from the PRF family and a random oracle. Pseudorandom functions are vital tools in the construction of cryptographic primitives, especially secure encryption schemes.

Pseudorandom generator

In theoretical computer science and cryptography, a pseudorandom generator (PRG) for a class of statistical tests is a deterministic procedure that maps a random seed to a longer pseudorandom string such that no statistical test in the class can distinguish between the output of the generator and the uniform distribution. The random seed itself is typically a short binary string drawn from the uniform distribution.

Pseudorandom permutation

In cryptography, a pseudorandom permutation (PRP) is a function that cannot be distinguished from a random permutation (that is, a permutation selected at random with uniform probability, from the family of all permutations on the function's domain) with practical effort.

Public Address

A public address is the cryptographic hash of a public key, allowing the user to use it as an address to request for payment.

Easy

Public Blockchain

A blockchain that can be accessed by anyone.

Easy

Public Key

A point on an elliptic curve derived from a private key via scalar multiplication — a one-way operation that cannot be reversed to recover the private key. Public keys are hashed to produce wallet addresses and embedded in scripts to define spending conditions. In SSP's multisig setup, both devices share their public keys to construct the joint spending script without revealing any private key.

Beginner

Public key certificate

In cryptography, a public-key certificate, also known as a digital certificate or identity certificate, is an electronic document used to prove the valid attribution of a public key to the identity of its holder. The certificate includes the public key and information about it, information about the identity of its owner, and the digital signature of an entity that has verified the certificate's contents.

Public key fingerprint

In public-key cryptography, a public key fingerprint is a short sequence of bytes used to identify a longer public key. Fingerprints are created by applying a cryptographic hash function to a public key. Since fingerprints are shorter than the keys they refer to, they can be used to simplify certain key management tasks. In Microsoft software, "thumbprint" is used instead of "fingerprint."

Public Sale

A public sale is the final stage of an ICO in which a company offers its token to the public at a significant discount before the token is listed on cryptocurrency exchanges.

Moderate

Public-Key Cryptography

Public-key cryptography is a collection of algorithms-based cryptographic procedures that are used to jumble secret data and make it look randomized.

Moderate

Public-Key Infrastructure

A public key infrastructure (PKI) is a collection of roles, rules, hardware, software, and processes for creating, managing, distributing, using, storing, and revoking digital certificates, as well as managing public-key encryption.

Hard

Publius (publishing system)

Publius was an attempted communication protocol developed by Lorrie Cranor, Avi Rubin and Marc Waldman to give individuals the ability to publish information on the web anonymously and with a high guarantee that their publications would not be censored or modified by a third party. The experiment terminated sometime in 2001 with no significant results. The name of the system was chosen to reflect the joint pen name of the authors of The Federalist Papers.

Pudgy Penguins

Pudgy Penguins is a blockchain-based collection of digital artwork composed of non-fungible tokens (NFTs). It is a collection of 8,888 unique NFTs launched on the Ethereum blockchain in August 2021.

Pump and Dump (P&D) Scheme

A form of fraud involving the artificial inflation of the price of a cryptocurrency with false and misleading positive statements.

Easy

PURB (cryptography)

In cryptography, a padded uniform random blob or PURB is a discipline for encrypted data formats designed to minimize unintended information leakage either from its encryption format metadata or from its total length.

Pure Proof of Stake (PPoS)

Pure Proof of Stake (PPoS) is Algorand’s consensus mechanism that allows random selection of validators based on the consistency of their stakes.

Hard

Put Option

A put option contract offers an owner the opportunity, but not the compulsion, to buy an underlying security at a certain price within a given time frame.

Easy

Puzzle friendliness

In cryptography, puzzle friendliness is a property of cryptographic hash functions. Not all cryptographic hash functions have this property. SHA-256 is a cryptographic hash function that is thought to have this property. Informally, a hash function is puzzle friendly if no solution exists which is better than just making random guesses, and the only way to find a solution is the brute force method. Although the property is very general, it is of particular importance to proof-of-work, such as in Bitcoin mining.

Pyramid Scheme

A pyramid scheme is a scam with a hierarchical top-down structure.

Easy

Q

QR Code

A machine-readable label that shows information encoded into a graphical black-and-white pattern.

Easy

QR Signing

A signing workflow where transaction data is exchanged between devices exclusively through QR codes rather than a network connection. One device displays the unsigned transaction as a QR; the signing device scans it, displays the details for confirmation, signs, and displays the result as a QR for the initiating device to scan. SSP supports QR signing as an air-gapped alternative to relay-based coordination.

Moderate

QRIS

Quick Response Code Indonesia Standard is a QR code payment system developed by Bank Indonesia (BI) and the Indonesian Payment System Association (ASPI) aimed to integrate all non-cash payment methods in Indonesia. Launched in 2019, the system enables peer-to-peer (P2P) transactions between banks and person-to-merchant (P2M) payments. All payment service providers (PJP) who uses QR code payments are required to implement QRIS. QRIS can be used by all smartphones with a QR code scanner to transfer funds. QRIS is also available as a near field communication (NFC) based payment under the name QRIS Tap.

Qstay

Qstay is a hospitality and property technology company headquartered in Dubai, United Arab Emirates. Founded in 2020, the company operates as a virtual hotel brand, managing a portfolio of short-term rental properties that it equips with standardized hotel-like services and amenities.

Quahl

Quahl, formerly known as Initiative Q, was an attempt to create a new payment network and digital currency. It was created by Israeli entrepreneur Saar Wilf, who previously founded Fraud Sciences, a payment security company acquired by PayPal. Quahl is backed by Cato Institute economist Lawrence H. White. The initiative has indicated it will not take measures to evade state regulation.

Quant Zone (FTX Exchange)

A tool to create and share trading strategies on the FTX exchange.

Moderate

Quantum Bit (Qubit)

A unit of measurement for the number of bits in quantum information, and is also called a "qubit."

Hard

Quantum Byzantine agreement

Byzantine fault tolerant protocols are algorithms that are robust to arbitrary types of failures in distributed algorithms. The Byzantine agreement protocol is an essential part of this task. The constant-time quantum version of the Byzantine protocol, is described below.

Quantum Computing

A computer that harnesses phenomena from quantum mechanics in order to perform much more efficient computations than older, classical computer technologies are capable of.

Moderate

Quantum fingerprinting

Quantum fingerprinting is a proposed technique that uses a quantum computer to generate a string with a similar function to the cryptographic hash function. Alice and Bob hold -bit strings and . Their goal and a referee's is to obtain the correct value of . To do this, quantum states are produced from the O(logn)-qubit state fingerprints and sent to the referee who performs the Swap test to detect if the fingerprints are similar or different with a high probability.

Quantum readout

Quantum readout is a method to verify the authenticity of an object. The method is secure provided that the object cannot be copied or physically emulated.

Quark (hash function)

Quark is a cryptographic hash function (family). It was designed by Jean-Philippe Aumasson, Luca Henzen, Willi Meier and María Naya-Plasencia.

Quasar Smart Contract (OMG Foundation)

A smart contract by OMG Network to solve layer-2 blockchain problems.

Moderate

Quorum (Governance

A quorum is the minimum number of members of an assembly or group that must be present at any of its meetings to make the proceedings of that meeting valid.

Hard

R

Radio Frequency Identification (RFID)

Radio Frequency Identification (RFID) is a type of technology that uses radio waves to passively identify a tagged item or individual.

Hard

RadioGatún

RadioGatún is a cryptographic hash primitive created by Guido Bertoni, Joan Daemen, Michaël Peeters, and Gilles Van Assche. It was first publicly presented at the NIST Second Cryptographic Hash Workshop, held in Santa Barbara, California, on August 24–25, 2006, as part of the NIST hash function competition. The same team that developed RadioGatún went on to make considerable revisions to this cryptographic primitive, leading to the Keccak SHA-3 algorithm.

Rage-quit

Rage-quit is the process where a member of a DAO exits part or all of their stake, leaves with a proportional share of the assets in the DAO’s treasury, and quits their participation.

Easy

Raiden Network

An off-chain scaling solution aiming to enable near-instant, low-fee and scalable payments on the Ethereum blockchain, similar to Bitcoin's proposed Lightning Network.

Moderate

Rain (cryptocurrency exchange)

Rain is a Middle Eastern cryptocurrency exchange company that operates through its holding company, Rain Financial Inc., which oversees Rain Management W.L.L. in Bahrain,

Rainbow table

A rainbow table is a precomputed table for caching the outputs of a cryptographic hash function, usually for cracking password hashes. Passwords are typically stored not in plain text form, but as hash values. If such a database of hashed passwords falls into the hands of attackers, they can use a precomputed rainbow table to recover the plaintext passwords. A common defense against this attack is to compute the hashes using a key derivation function that adds a "salt" to each password before hashing it, with different passwords receiving different salts, which are stored in plain text along with the hash.

Random oracle

In cryptography, a random oracle is an oracle that responds to every unique query with a (truly) random response chosen uniformly from its output domain. If a query is repeated, it responds the same way every time that query is submitted.

Randomness

In common usage, randomness is the apparent or actual lack of definite patterns or predictability in information. A random sequence of events, symbols or steps often has no order and does not follow an intelligible pattern or combination. Individual random events are, by definition, unpredictable, but if there is a known probability distribution, the frequency of different outcomes over repeated events is predictable. For example, when throwing two dice, the outcome of any particular roll is unpredictable, but a sum of 7 will tend to occur twice as often as 4. In this view, randomness is not haphazardness; it is a measure of uncertainty of an outcome. Randomness applies to concepts of chance, probability, and information entropy.

Rank

The relative position of a cryptocurrency by market capitalization.

Moderate

Ransomware

Ransomware is a type of malware used by hackers to steal or encrypt their victims’ files to extort them for a ransom in exchange for file decryption or restoration.

Easy

RCCA security

Replayable CCA security is a security notion in cryptography that relaxes the older notion of Security against Chosen-Ciphertext Attack : all CCA-secure systems are RCCA secure but the converse is not true. The claim is that for a lot of use cases, CCA is too strong and RCCA suffices. Nowadays a certain amount of cryptographic scheme are proved RCCA-secure instead of CCA secure. It was introduced in 2003 in a research publication by Ran Canetti, Hugo Krawczyk and Jesper B. Nielsen.

Real World Assets (RWAs)

Real World Assets are off-chain assets, which are tokenized and brought on-chain for use in DeFi. Tokenization involves converting an asset's value into a digital token for representation and transactions on the blockchain.

Easy

Rebalancing

Rebalancing is the process of realigning the weightage of a portfolio of assets, that involves buying or selling assets periodically to maintain a targeted level of asset allocation and risk.

Easy

Rebase

A token designed so that the circulating supply adjusts automatically according to price fluctuations.

Moderate

Recovery Phrase

A synonym for seed phrase or mnemonic — the sequence of 12 or 24 words generated by a BIP-39 wallet that can reconstruct all private keys in the wallet. The term is common in wallet UIs because it emphasizes the phrase's role in recovering access after device loss or failure. SSP generates two independent recovery phrases, one per device, and each must be backed up separately.

Beginner

Recovery Seed

A recovery seed is a cryptographically derived security code composed of a list of random words, typically ranging between 12 and 14.

Moderate

Recursion

Recursion refers to when a function calls on itself directly or indirectly in a circular loop(s).

Hard

Regulation is when something is controlled by a specific set of rules.

Easy

Regulation of algorithms

Regulation of algorithms, or algorithmic regulation, is the creation of laws, rules and public sector policies for promotion and regulation of algorithms, particularly in artificial intelligence and machine learning. For the subset of AI algorithms, the term regulation of artificial intelligence is used. The regulatory and policy landscape for artificial intelligence (AI) is an emerging issue in jurisdictions globally, including in the European Union. Regulation of AI is considered necessary to both encourage AI and manage associated risks, but challenging. Another emerging topic is the regulation of blockchain algorithms and is mentioned along with regulation of AI algorithms. Many countries have enacted regulations of high frequency trades, which is shifting due to technological progress into the realm of AI algorithms.

Ring CT (Confidential Transactions)

RingCT is how transaction amounts are hidden in Monero.

Hard

Ring Miners

Ring miners are network participants in the Loopring protocol who manage order rings and ensure trades are completed for all parties involved.

Moderate

Ring Signature

A cryptographic digital signature that obfuscates the identities of two parties within a transaction.

Moderate

Rough consensus, in its bare essence, refers to a method of decision-making that doesn't necessarily require unanimity.

Moderate

Round (cryptography)

In cryptography, a round or round function is a basic transformation that is repeated (iterated) multiple times inside the algorithm. Splitting a large algorithmic function into rounds simplifies both implementation and cryptanalysis.

Royal Mint Gold

Royal Mint Gold was a digital gold currency and a cryptocurrency backed by gold reserves in the UK Royal Mint. The Royal Mint launched a digitized token called RMG, representing one gram of physical gold per token, in 2016. It began testing blockchain transactions in April 2017. The first test transaction was in August 2017. The rollout was originally scheduled to occur by the end of 2017. US-based CME Group was tentatively set to administer the trading. At the time, The Daily Telegraph said it "appears somewhat similar to an exchange-traded fund such as ETF Securities Physical Gold".

RSA Award for Excellence in Mathematics

Formally called since 2025 The RSAC Conference Award for Excellence in Mathematics, is an annual award. It is announced at the annual RSA Conference in recognition of innovations and contributions in the field of cryptography. An award committee of experts, which is associated with the Cryptographer's Track committee at the RSA Conference (CT-RSA), nominates to the award persons who are pioneers in their field, and whose work has had applied or theoretical lasting value; the award is typically given for the lifetime achievements throughout the nominee's entire career. Nominees are often affiliated with universities or involved with research and development in the information technology industry. The award is cosponsored by the International Association for Cryptologic Research.

RSA problem

Salt (cryptography)

In cryptography, a salt is random data fed as an additional input to a one-way function that hashes data, a password or passphrase. Salting helps defend against attacks that use precomputed tables, by vastly growing the size of table needed for a successful attack. It also helps protect passwords that occur multiple times in a database, as a new salt is used for each password instance. Additionally, salting does not place any burden on users.

Salted Challenge Response Authentication Mechanism

In cryptography, the Salted Challenge Response Authentication Mechanism (SCRAM) is a family of modern, password-based challenge–response authentication mechanisms providing authentication of a user to a server. As it is specified for Simple Authentication and Security Layer (SASL), it can be used for password-based logins to services like LDAP, HTTP, SMTP, POP3, IMAP and JMAP (e-mail), XMPP (chat), or MongoDB and PostgreSQL (databases). For XMPP, supporting it is mandatory.

Samourai Wallet

Samourai Wallet was a privacy-focused Bitcoin wallet that uses a Coinjoin tool that mixes a Bitcoin transaction with other transactions. It is open source and was released in 2015 and operated until 2024. In April 2024, it was targeted by the U.S. Department of Justice, alleging that the service enabled money laundering.

SANDstorm hash

The SANDstorm hash is a cryptographic hash function designed in 2008 by Mark Torgerson, Richard Schroeppel, Tim Draelos, Nathan Dautenhahn, Sean Malone, Andrea Walker, Michael Collins, and Hilarie Orman for the NIST SHA-3 competition.

Sansar (video game)

Sansar is a social virtual reality platform, for Microsoft Windows only, developed by the San Francisco-based firm Linden Lab, and now owned by Sansar Inc. It launched in "creator beta" to the general public on July 31, 2017. The platform enables user-created 3D spaces where people can create and share interactive social experiences, such as playing games, watching videos, and having conversations in VR. Each participant is represented by a detailed avatar that is the graphical representation of the user, including speech-driven facial animations and motion-driven body animations.

Satoshi (SATS)

The smallest unit of bitcoin with a value of 0.00000001 BTC.

Moderate

Satoshi Nakamoto

The individual or group of individuals that created Bitcoin.

Easy

In telecommunications, a scrambler is a device that transposes or inverts signals or otherwise encodes a message at the sender's side to make the message unintelligible at a receiver not equipped with an appropriately set descrambling device. Whereas encryption usually refers to operations carried out in the digital domain, scrambling usually refers to operations carried out in the analog domain. Scrambling is accomplished by the addition of components to the original signal or the changing of some important component of the original signal in order to make extraction of the original signal difficult. Examples of the latter might include removing or changing vertical or horizontal sync pulses in television signals; televisions will not be able to display a picture from such a signal. Some modern scramblers are actually encryption devices, the name remaining due to the similarities in use, as opposed to internal operation.

Script

A computer script is a list of commands that are executed by a certain program or scripting language.

Moderate

Script Type

The category of Bitcoin locking script applied to an output, which determines how funds can be spent and what address format is used. Common script types are P2PKH (Legacy), P2SH (Script Hash), P2WPKH (native SegWit single-key), P2WSH (native SegWit script), and P2TR (Taproot). SSP multisig outputs use P2WSH; the script type affects fee cost, privacy, and hardware wallet compatibility.

Advanced

Scripting Programming Language

A scripting language is a programming language that does not require the compilation step. It uses a high-level construct to carry out one command at a time.

Hard

Scrypt

An alternative proof-of-work (PoW) algorithm to SHA-256, used in Bitcoin mining. Scrypt mining relies more heavily on memory than on pure CPU power, aiming to reduce the advantage that ASICs have and hence increasing network participation and energy efficiency.

Moderate

SCVP

The Server-based Certificate Validation Protocol (SCVP) is an Internet protocol for determining the path between an X.509 digital certificate and a trusted root and the validation of that path according to a particular validation policy.

Searchable symmetric encryption

Searchable symmetric encryption (SSE) is a form of encryption that allows efficient searching over a collection of encrypted documents or files without requiring decryption. SSE can be used to outsource files to an untrusted cloud storage server without revealing the files in plaintext, while preserving the server's ability to perform searches over them.

Second-Layer Solutions

A set of solutions built on top of a public blockchain to extend its scalability and efficiency, especially for micro-transactions or actions. Examples include Plasma, TrueBit, Lightning Network and more.

Moderate

Secondary Market

A secondary market is a place where investors or traders can buy and sell different kinds of assets or securities that they own, with others.

Easy

Secure Asset Fund for Users (SAFU)

SAFU is the acronym for the "Secure Asset Fund for Users," an insurance fund established by Binance for emergency cases.

Easy

Secure channel

In cryptography, a secure channel is a means of data transmission that is resistant to overhearing and tampering. A confidential channel is a means of data transmission that is resistant to overhearing, or eavesdropping, but not necessarily resistant to tampering. An authentic channel is a means of data transmission that is resistant to tampering but not necessarily resistant to overhearing.

Secure Communications Interoperability Protocol

The Secure Communications Interoperability Protocol (SCIP) is a US standard for secure voice and data communication, for circuit-switched one-to-one connections, not packet-switched networks. SCIP derived from the US Government Future Narrowband Digital Terminal (FNBDT) project. SCIP supports a number of different modes, including national and multinational modes which employ different cryptography. Many nations and industries develop SCIP devices to support the multinational and national modes of SCIP.

Secure copy protocol

Secure copy protocol (SCP) is a means of securely transferring computer files between a local host and a remote host or between two remote hosts. It is based on the Secure Shell (SSH) protocol. "SCP" commonly refers to both the Secure Copy Protocol and the program itself.

Secure Element

A secure element is a type of hardware chip that runs a specified number of applications.

Moderate

Secure Hash Algorithms

The Secure Hash Algorithms are a family of cryptographic hash functions published by the National Institute of Standards and Technology (NIST) as a U.S. Federal Information Processing Standard (FIPS), including:SHA-0: A retronym applied to the original version of the 160-bit hash function published in 1993 under the name "SHA". It was withdrawn shortly after publication due to an undisclosed "significant flaw" and replaced by the slightly revised version SHA-1. SHA-1: A 160-bit hash function which resembles the earlier MD5 algorithm. This was designed by the National Security Agency (NSA) to be part of the Digital Signature Algorithm. Cryptographic weaknesses were discovered in SHA-1, and the standard was no longer approved for most cryptographic uses after 2010. SHA-2: A family of two similar hash functions, with different block sizes, known as SHA-256 and SHA-512. They differ in the word size; SHA-256 uses 32-bit words where SHA-512 uses 64-bit words. There are also truncated versions of each standard, known as SHA-224, SHA-384, SHA-512/224 and SHA-512/256. These were also designed by the NSA. SHA-3: A hash function formerly called Keccak, chosen in 2012 after a public competition among non-NSA designers. It supports the same hash lengths as SHA-2, and its internal structure differs significantly from the rest of the SHA family.

Secure Hypertext Transfer Protocol

Secure Hypertext Transfer Protocol (S-HTTP) is an obsolete alternative to the HTTPS protocol for encrypting web communications carried over the Internet. It was developed by Eric Rescorla and Allan M. Schiffman at Enterprise Integration Technologies in 1994 and published in 1999 as RFC 2660. Netscape's dominance of the browser market led to HTTPS becoming the de facto method for securing web communications.

Secure key issuing cryptography

Secure key issuing is a variant of Identity-based cryptography that reduces the level of trust that needs to be placed in a trusted third party by spreading the trust across multiple third parties.

Secure multi-party computation

Secure multi-party computation is a subfield of cryptography with the goal of creating methods for parties to jointly compute a function over their inputs while keeping those inputs private. Unlike traditional cryptographic tasks, where cryptography assures security and integrity of communication or storage and the adversary is outside the system of participants, the cryptography in this model protects participants' privacy from each other.

Secure Multi-Party Computation (sMPC)

SMPC is a subfield of cryptography that allows parties to compute a function while keeping the inputs private.

Moderate

Secure Neighbor Discovery

The Secure Neighbor Discovery (SEND) protocol is a security extension of the Neighbor Discovery Protocol (NDP) in IPv6 defined in RFC 3971 and updated by RFC 6494.

Secure Proof of Stake (SPoS)

Secure Proof of Stake (SPoS) is a consensus mechanism used to secure blockchain networks. It is an evolution of the traditional proof-of-stake (PoS) consensus algorithm

Easy

Secure Real-time Transport Protocol

The Secure Real-time Transport Protocol (SRTP) is a profile for Real-time Transport Protocol (RTP) intended to provide encryption, message authentication and integrity, and replay attack protection to the RTP data in both unicast and multicast applications. It was developed by a small team of Internet Protocol and cryptographic experts from Cisco and Ericsson. It was first published by the IETF in March 2004 as RFC 3711.

Secure two-party computation

Secure two-party computation is a sub-problem of secure multi-party computation (MPC) that has received special attention by researchers because of its close relation to many cryptographic tasks. The goal of 2PC is to create a generic protocol that allows two parties to jointly compute an arbitrary function on their inputs without sharing the value of their inputs with the opposing party. One of the most well known examples of 2PC is Yao's Millionaires' problem, in which two parties, Alice and Bob, are millionaires who wish to determine who is wealthier without revealing their wealth. Formally, Alice has wealth , Bob has wealth , and they wish to compute without revealing the values or .

Secure voice

Secure voice is a term in cryptography for the encryption of voice communication over a range of communication types such as radio, telephone or IP.

Securities and Exchange Commission (SEC)

An independent agency of the United States federal government, responsible for enforcing federal securities laws, proposing securities rules, and regulating the securities industry, the nation's stock and options exchanges, and other related activities and organizations.

Moderate

Security

The term securities refers to a fungible and tradable financial instrument that carries a type of monetary value.

Easy

Security association

A security association (SA) is the establishment of shared security attributes between two network entities to support secure communication. An SA may include attributes such as: cryptographic algorithm and mode; traffic encryption key; and parameters for the network data to be passed over the connection. The framework for establishing security associations is provided by the Internet Security Association and Key Management Protocol (ISAKMP). Protocols such as Internet Key Exchange (IKE) and Kerberized Internet Negotiation of Keys (KINK) provide authenticated keying material.

Security level

In cryptography, security level is a measure of the strength that a cryptographic primitive — such as a cipher or hash function — achieves. Security level is usually expressed as a number of "bits of security", where n-bit security means that the attacker would have to perform 2n operations to break it, but other methods have been proposed that more closely model the costs for an attacker. This allows for convenient comparison between algorithms and is useful when combining multiple primitives in a hybrid cryptosystem, so there is no clear weakest link. For example, AES-128 is designed to offer a 128-bit security level, which is considered roughly equivalent to a RSA using 3072-bit key.

Security of cryptographic hash functions

In cryptography, cryptographic hash functions can be divided into two main categories. In the first category are those functions whose designs are based on mathematical problems, and whose security thus follows from rigorous mathematical proofs, complexity theory and formal reduction. These functions are called provably secure cryptographic hash functions. To construct these is very difficult, and few examples have been introduced. Their practical use is limited.

Security parameter

In cryptography, a security parameter is a way of measuring of how "hard" it is for an adversary to break a cryptographic scheme. There are two main types of security parameter: computational and statistical, often denoted by and , respectively. Roughly speaking, the computational security parameter is a measure for the input size of the computational problem on which the cryptographic scheme is based, which determines its computational complexity, whereas the statistical security parameter is a measure of the probability with which an adversary can break the scheme.

Security protocol notation

In cryptography, security (engineering) protocol notation, also known as protocol narrations and Alice & Bob notation, is a way of expressing a protocol of correspondence between entities of a dynamic system, such as a computer network. In the context of a formal model, it allows reasoning about the properties of such a system.

Security Protocols Open Repository

SPORE, the Security Protocols Open Repository, is an online library of security protocols with comments and links to papers. Each protocol is downloadable in a variety of formats, including rules for use with automatic protocol verification tools. All protocols are described using BAN logic or the style used by Clark and Jacob, and their goals. The database includes details on formal proofs or known attacks, with references to comments, analysis & papers. A large number of protocols are listed, including many which have been shown to be insecure.

Security through obscurity

In security engineering, security through obscurity is the practice of concealing the details or mechanisms of a system to enhance its security. This approach relies on the principle of hiding something in plain sight, akin to a magician's sleight of hand or the use of camouflage. It diverges from traditional security methods, such as physical locks, and is more about obscuring information or characteristics to deter potential threats. Examples of this practice include disguising sensitive information within commonplace items, like a piece of paper in a book, or altering digital footprints, such as spoofing a web browser's version number. While not a standalone solution, security through obscurity can complement other security measures in certain scenarios.

Security Token

A security token is essentially a digital form of traditional securities.

Easy

Security Token Offering

A security token offering (STO) is a public offering where tokenized digital securities are sold.

Moderate

Seed Funding

Seed funding is a type of funding that provides capital to startups in exchange for equity in the company.

Easy

Seed Leak

The unintentional exposure of a BIP-39 seed phrase or the entropy it was derived from, whether through a photo, cloud backup, clipboard, or insecure note. A seed leak gives an attacker complete, irrevocable access to all funds in the wallet. SSP mitigates seed leak risk partly through its 2-of-2 structure: even if one device's seed is leaked, the attacker still lacks the second key.

Beginner

Seed Phrase

A single starting point when deriving keys for a deterministic wallet.

Moderate

Seed Phrase

A human-readable backup of a wallet's private key, encoded as 12 or 24 dictionary words via BIP-39. Anyone with the phrase can recreate the wallet on any device, so it must be stored offline and never typed into a website or photographed. SSP generates two independent seed phrases — one per device — and you back up each separately.

Beginner

Segregated Witness (SegWit)

A Bitcoin Improvement Proposal (BIP) that aimed to fix transaction malleability on Bitcoin.

Hard

SegWit

Segregated Witness (SegWit), formally known as Segregated Witness (Consensus layer), is an implemented soft fork change in the transaction format of bitcoin.

Self-shrinking generator

A self-shrinking generator is a pseudorandom generator that is based on the shrinking generator concept. Variants of the self-shrinking generator based on a linear-feedback shift register (LFSR) are studied for use in cryptography.

Selfish Mining

A situation in which a miner mines a new block but does not broadcast this new block to the other miners.

Hard

Sell Wall

A situation where a large limit order has been placed to sell when a cryptocurrency reaches a certain value.

Moderate

Semantic Web

The ambition of the Semantic Web is to enable computers to manipulate information on our behalf.

Hard

Sender Keys

In cryptography, Sender Keys is a variant of the Signal Protocol used in end-to-end encryption used in instant messaging. Sender Keys is used for group chats. Applications using it have included Signal, Matrix, WhatsApp, Session, and Facebook Messenger.

Serge Belamant

Serge Belamant is a French-born South African entrepreneur best known for designing the Universal Electronic Payment System (UEPS) and the Chip Offline Pre-authorised Card (COPAC).

Series B Funding

A Series B funding round is the second round of funding a business.

Moderate

Server-based signatures

In cryptography, server-based signatures are digital signatures in which a publicly available server participates in the signature creation process. This is in contrast to conventional digital signatures that are based on public-key cryptography and public-key infrastructure. With that, they assume that signers use their personal trusted computing bases for generating signatures without any communication with servers.

Server-Gated Cryptography

Server-Gated Cryptography (SGC), also known as International Step-Up by Netscape, is a defunct mechanism that was used to step up from 40-bit or 56-bit to 128-bit cipher suites with SSL. It was created in response to United States federal legislation on the export of strong cryptography in the 1990s. The legislation had limited encryption to weak algorithms and shorter key lengths in software exported outside of the United States of America. When the legislation added an exception for financial transactions, SGC was created as an extension to SSL with the certificates being restricted to financial organisations. In 1999, this list was expanded to include online merchants, healthcare organizations, and insurance companies. This legislation changed in January 2000, resulting in vendors no longer shipping export-grade browsers and SGC certificates becoming available without restriction.

Settlement

Settlement refers to the process in which a user executes limit or market orders on an order-book-based DEX.

Easy

Settlement Layer

A settlement layer is a layer that essentially provides an anchor for an entire ecosystem.

Moderate

SFINKS

In cryptography, SFINKS is a stream cypher algorithm developed by An Braeken, Joseph Lano, Nele Mentens, Bart Preneel, and Ingrid Verbauwhede. It includes a message authentication code. It has been submitted to the eSTREAM Project of the eCRYPT network. In 2005, Nicolas T. Courtois noted that, while the cipher is elegant and secure against some simple algebraic attacks, it is vulnerable to more elaborate known attacks.

SFOX

sFOX is a cryptocurrency prime dealer and trading platform founded in 2014.

SHA-1

In cryptography, SHA-1 is a hash function which takes an input and produces a 160-bit (20-byte) hash value known as a message digest – typically rendered as 40 hexadecimal digits. It was designed by the United States National Security Agency, and is a U.S. Federal Information Processing Standard. The algorithm has been cryptographically broken but is still widely used.

SHA-2

SHA-2 is a set of cryptographic hash functions designed by the United States National Security Agency (NSA) and first published in 2001. They are built using the Merkle–Damgård construction, from a one-way compression function itself built using the Davies–Meyer structure from a specialized block cipher.

SHA-256

A cryptographic hash function that generates a 256-bit signature for a text, used in Bitcoin proof-of-work (PoW).

Hard

SHA-3

SHA-3 is the latest member of the Secure Hash Algorithm family of standards, released by NIST on August 5, 2015. Although part of the same series of standards, SHA-3 is internally different from the MD5-like structure of SHA-1 and SHA-2.

Shabal

Shabal is a cryptographic hash function submitted by the France-funded research project Saphir to NIST's international competition on hash functions.

Shanghai Upgrade

The Shanghai Upgrade will allow users to unstake and withdraw their ETH from the network.

Moderate

A short squeeze is an unusual market condition that causes the price of a coin to rise quickly, encouraging traders (who are betting against the price of the token) to buy it to avoid losses.

Easy

Short Weather Cipher

The Short Weather Cipher, also known as the weather short signal book, was a cipher, presented as a codebook, that was used by the radio telegraphists aboard U-boats of the German Navy (Kriegsmarine) during World War II. It was used to condense weather reports into a short 7-letter message, which was enciphered by using the naval Enigma and transmitted by radiomen to intercept stations on shore, where it was deciphered by Enigma and the 7-letter weather report was reconstructed.

Side Channel

An attack that extracts secret information by measuring physical or environmental characteristics of a device — power consumption, electromagnetic emissions, timing variations, or acoustic noise — rather than by exploiting logical flaws in the algorithm. Hardware wallets use secure elements with countermeasures such as constant-time operations and power-line filtering to resist side-channel attacks during key operations.

Advanced

Side Channel Attack

A side channel attack is a hacking method that exploits a computer’s inherent “tells" that unintentionally convey information.

Moderate

Sidechain

A sidechain is a separate blockchain, tied to its parent blockchain via a two-way peg.

Hard

Sighash

A flag in a Bitcoin transaction signature that specifies which parts of the transaction the signature commits to. SIGHASH_ALL (default) signs all inputs and outputs; SIGHASH_NONE signs inputs but no outputs; SIGHASH_SINGLE signs the input and the corresponding output. The sighash type is appended to the DER-encoded signature and affects what aspects of a transaction can be modified after signing.

Advanced

SIGINT Activity Designator

A SIGINT Activity Designator identifies a signals intelligence (SIGINT) line of collection activity associated with a signals collection station, such as a base or a ship. For example, the SIGAD for Menwith Hill in the UK is USD1000. SIGADs are used by the signals intelligence agencies of Australia, Canada, New Zealand, the United Kingdom, and the United States.

Signal

Signals are a call to action to either buy or sell an asset.

Easy

Signal Protocol

The Signal Protocol is a non-federated cryptographic protocol that provides end-to-end encryption for voice and instant messaging conversations. The protocol was developed by Open Whisper Systems in 2013 and was introduced in the open-source TextSecure app, which later became Signal. Several closed-source applications have implemented the protocol, such as WhatsApp, which is said to encrypt the conversations of "more than a billion people worldwide" or Google who provides end-to-end encryption by default to all RCS-based conversations between users of their Google Messages app for one-to-one conversations. Facebook Messenger also say they offer the protocol for optional "Secret Conversations", as did Skype for its "Private Conversations".

Signals intelligence

Signals intelligence (SIGINT) is the act and field of intelligence-gathering by interception of signals, whether communications between people or from electronic signals not directly used in communication. As classified and sensitive information is usually encrypted, signals intelligence may necessarily involve cryptanalysis. Traffic analysis—the study of who is signaling to whom and in what quantity—is also used to integrate information, and it may complement cryptanalysis.

Signature

A cryptographic value computed from a private key and a message hash that proves the key holder authorized the message without revealing the key itself. On Bitcoin, signatures are ECDSA (Legacy/SegWit) or Schnorr (Taproot); on Ethereum, ECDSA over secp256k1. Signatures are the fundamental primitive that authorizes every on-chain transaction.

Beginner

Signature Record Type Definition

In near field communications the NFC Forum Signature Record Type Definition (RTD) is a security protocol used to protect the integrity and authenticity of NDEF Messages. The Signature RTD is an open interoperable specification modeled after Code signing where the trust of signed messages is tied to digital certificates.

A lightweight client to verify blockchain transactions.

Moderate

Simultaneous Authentication of Equals

In cryptography, Simultaneous Authentication of Equals (SAE) is a password-based authentication and password-authenticated key agreement method.

SIPRNet

The Secret Internet Protocol Router Network (SIPRNet) is "a system of interconnected computer networks used by the U.S. Department of Defense and the U.S. Department of State to transmit classified information by packet switching over the 'completely secure' environment". It also provides services such as hypertext document access and electronic mail.

Skein (hash function)

Skein is a cryptographic hash function and one of five finalists in the NIST hash function competition. Entered as a candidate to become the SHA-3 standard, the successor of SHA-1 and SHA-2, it ultimately lost to NIST hash candidate Keccak.

Skrill

Skrill is part of Paysafe Limited, a global payments platform. It is one of Paysafe's digital wallet brands and was established in 2001 to offer multiple online payment and money transfer services. Skrill operates in more than 100 countries with the digital wallet offered in more than 40 currencies. The company facilitates multiple payment options including card payments, bank transfers and local payment methods. The funds in a Skrill account can then be used to pay merchants and other Skrill users or converted into cryptocurrency.

Skynet

A platform built on Sia blockchain for decentralized content storage.

Moderate

Slashing

A penalty mechanism in proof-of-stake protocols that destroys part of a validator's staked collateral for provable misbehavior — specifically double voting (signing two conflicting blocks at the same height) or surround voting. Slashing creates strong economic disincentives against attacks and is enforced automatically by the protocol. A slashed validator is also forcibly ejected from the validator set.

Advanced

Slippage

Slippage happens when traders have to settle for a different price than what they initially requested due to a price movement.

Easy

Slot (Cardano)

The smallest time period in the Cardano blockchain.

Hard

SM3 (hash function)

ShangMi 3 (SM3) is a cryptographic hash function, standardised for use in commercial cryptography in China. It was published by the State Cryptography Administration on 2010-12-17 as "GM/T 0004-2012: SM3 cryptographic hash algorithm".

Smart treasury is a mechanism for automatic buyback of project tokens in the DeFi industry.

Moderate

Smart-ID

Smart-ID is an electronic authentication tool developed by SK ID Solutions, an Estonian company. Users can log in to various electronic services and sign documents with an electronic signature.

SMASH (hash)

SMASH is a cryptographic hash function which was created by Lars R. Knudsen. SMASH comes in two versions: 256-bit and 512-bit. Each version was supposed to rival SHA-256 and SHA-512, respectively, however, shortly after the SMASH presentation at FSE 2005, an attack vector against SMASH was discovered which left the hash broken.

Snake oil (cryptography)

In cryptography, snake oil is any cryptographic method or product considered to be bogus or fraudulent. The name derives from snake oil, one type of patent medicine widely available in 19th century United States.

Snapshot

A snapshot in the blockchain world is the act of documenting the status of a blockchain at a specific block height.

Moderate

A software token is a piece of a two-factor authentication security device that may be used to authorize the use of computer services. Software tokens are stored on a general-purpose electronic device such as a desktop computer, laptop, PDA, or mobile phone and can be duplicated.

Software Wallet

A software wallet, also known as a wallet app, is an application that allows users to HODL, send, and receive cryptocurrencies.

Easy

Solana (blockchain platform)

Solana is a public blockchain platform that uses a proof-of-stake consensus mechanism and provides smart contract functionality. The platform's native cryptocurrency is SOL. Solana was founded in 2018 by Toly Yakovenko and Raj Gokal, and the network was launched in March 2020 by their San Francisco-based company, Solana Labs.

Solana Virtual Machine (SVM)

The Solana Virtual Machine, or SVM, is the system powering Solana's ability to handle thousands of transactions per second.

Moderate

Solidity

The programming language used by Ethereum for developing smart contracts.

Moderate

Source Code

A collection of lines or computer-executable commands written in a high-level language is called a source code.

Easy

South Park: Post COVID: The Return of COVID

"South Park: Post COVID: The Return of COVID" is a 2021 American adult animated comedy television special episode written and directed by Trey Parker. It is the second in a series of South Park television specials for the streaming service Paramount+ and premiered on December 16, 2021. It is a sequel to and continues the storyline of the previous special, "South Park: Post COVID". It is also the 311th episode of the series.

Sovereign Currency Act of 2018

Sovereign Currency Act of 2018 was a statute of the Legislature of the Marshall Islands which was passed on February 26, 2018. The act created and issued a digital decentralized currency ("cryptocurrency") that is used as a legal tender of the Marshall Islands.

SPAC

Simple and Protected GSSAPI Negotiation Mechanism (SPNEGO), often pronounced "spenay-go", is a GSSAPI "pseudo mechanism" used by client-server software to negotiate the choice of security technology. SPNEGO is used when a client application wants to authenticate to a remote server, but neither end is sure what authentication protocols the other supports. The pseudo-mechanism uses a protocol to determine what common GSSAPI mechanisms are available, selects one and then dispatches all further security operations to it. This can help organizations deploy new security mechanisms in a phased manner.

Stacks, formerly Blockstack, is a Bitcoin layer-2 blockchain.

Stagflation

Stagflation is a period during which an economy sees simultaneous stagnant growth and rising inflation (in other words, growth and inflation move in opposite directions).

Easy

Staking

The act of locking cryptocurrency as collateral in a proof-of-stake network to participate in block validation and earn rewards. On Ethereum, validators stake exactly 32 ETH and are selected pseudo-randomly to propose and attest to blocks. Staking rewards compensate validators for honest participation; misbehavior can result in slashing — the partial or full loss of staked funds.

Moderate

Staking Pool

Staking Pools allows users to combine their resources in order to increase their chances of earning rewards. This mechanism offers more staking power to the network to verify and validate new blocks.

Hard

Stale Block

A block which was successfully mined but not included on the current longest blockchain, usually because another block at the same height was added to the chain first.

Moderate

StarkWare Industries

StarkWare Industries is an Israeli software company that specializes in cryptography. It develops zero-knowledge proof technology that compresses information to address the scalability problem of the blockchain, and works on the Ethereum platform. In May 2022, the company's estimated value was $8 billion, an increase from $2 billion six months earlier.

State Channel

A second-layer scaling solution that reduces the total on-chain transactions necessary, moving the transactions off-chain and letting participants sign to the main chain after multiple off-chain transactions.

Moderate

Statistical distance

In statistics, probability theory, and information theory, a statistical distance quantifies the distance between two statistical objects, which can be two random variables, or two probability distributions or samples, or the distance can be between an individual sample point and a population or a wider sample of points.

Stegomalware

Stegomalware is a form of malicious software that leverages steganography techniques to conceal its code, configuration data, or command-and-control (C&C) communications within seemingly benign digital media such as images, audio files, videos, documents, or network traffic. It typically embeds encrypted or obfuscated payloads into digital media and only extracts and executes them at runtime, which makes traditional signature-based and sandbox-based detection significantly more difficult. Stegomalware has been observed in attacks ranging from advanced persistent threats (APTs) to financially motivated cybercrime, and is now the subject of dedicated academic surveys, research projects, and international law-enforcement initiatives.

StormPay of TN was an electronic money auction payment processor run by Stormpay Incorporated, a Clarksville, Tennessee, United States company founded in October 2002. It allowed anyone with an e-mail address to buy or sell StormPay Auction items after opening an online account.

Stream cipher

A stream cipher is a symmetric key cipher where plaintext digits are combined with a pseudorandom cipher digit stream (keystream). In a stream cipher, each plaintext digit is encrypted one at a time with the corresponding digit of the keystream, to give a digit of the ciphertext stream. Since encryption of each digit is dependent on the current state of the cipher, it is also known as state cipher. In practice, a digit is typically a bit and the combining operation is an exclusive-or (XOR).

Streebog

Streebog is a cryptographic hash function defined in the Russian national standard GOST R 34.11-2012 Information Technology – Cryptographic Information Security – Hash Function. It was created to replace an obsolete GOST hash function defined in the old standard GOST R 34.11-94, and as an asymmetric reply to SHA-3 competition by the US National Institute of Standards and Technology. The function is also described in RFC 6986 and one out of hash functions in ISO/IEC 10118-3:2018.

Strong cryptography

Strong cryptography or cryptographically strong are general terms used to designate the cryptographic algorithms that, when used correctly, provide a very high level of protection against any eavesdropper, including the government agencies. There is no precise definition of the boundary line between the strong cryptography and (breakable) weak cryptography, as this border constantly shifts due to improvements in hardware and cryptanalysis techniques. These improvements eventually place the capabilities once available only to the NSA within the reach of a skilled individual, so in practice there are only two levels of cryptographic security, "cryptography that will stop your kid sister from reading your files, and cryptography that will stop major governments from reading your files".

Strong secrecy

Strong secrecy is a term used in formal proof-based cryptography for making propositions about the security of cryptographic protocols. It is a stronger notion of security than syntactic secrecy. Strong secrecy is related with the concept of semantic security or indistinguishability used in the computational proof-based approach. Bruno Blanchet provides the following definition for strong secrecy:Strong secrecy means that an adversary cannot see any difference when the value of the secret changes

Stroop

A stroop is the smallest unit of Lumen (XLM).

Easy

Structured encryption

Structured encryption (STE) is a form of encryption that encrypts a data structure so that it can be privately queried. Structured encryption can be used as a building block to design end-to-end encrypted databases, efficient searchable symmetric encryption (SSE) and other algorithms that can be efficiently executed on encrypted data.

Subgraph Manifest

A component of Subgraph that entails information pertaining to subgraph’s data sources, templates, and more.

Hard

Subliminal channel

In cryptography, subliminal channels are covert channels that can be used to communicate secretly in normal looking communication over an insecure channel. Subliminal channels in digital signature crypto systems were found in 1984 by Gustavus Simmons.

Subnet

A subnet is a smaller network within a larger network. Think of all the computers, printers and other devices that make up a network as pieces of a huge jigsaw puzzle. A subnet is like a chunk of that jigsaw; it collects nodes that all have something in common.

Moderate

Substrate

Substrate is a web app development framework developed by Parity Technologies.

Hard

Succinct Proofs of Random Access (SPoRA)

Succinct Proofs of Random Access (SPoRA) is a consensus mechanism used to confirm transactions and validate blocks on the Arweave decentralized network.

Easy

Sum-check protocol

A sum-check protocol is a cryptographic protocol for the construction of interactive proof systems, used widely in zero-knowledge protocols.

Supercomputer

A supercomputer is a superior version of a general-purpose computer, which has a significantly increased capacity and processing power.

Easy

Supercycle

In economics, a "supercycle" describes an extended period characterized by the outsized growth of a particular asset or sector.

Easy

In cryptography, SWIFFT is a collection of provably secure hash functions. It is based on the concept of the fast Fourier transform (FFT). SWIFFT is not the first hash function based on the FFT, but it sets itself apart by providing a mathematical proof of its security. It can be shown that finding collisions in SWIFFT is at least as difficult as finding short vectors in cyclic/ideal lattices in the worst case. By giving a security reduction to the worst case of a difficult mathematical problem, SWIFFT gives a much stronger security guarantee than most other cryptographic hash functions.

Swing Failure Pattern (SFP)

A swing failure pattern (SFP) is a trend reversal indicator that can be used to discover a weakness in the current trend and identify early reversal signs.

Easy

Swing Trading

Swing trading is a market trading technique that aims to profit from short to medium-term price changes in stocks, commodities, and/or currencies over a period of days or weeks.

Easy

Sybil Attack

Sybil attacks undermine an online network by creating many IDs, accounts or nodes to upset the balance of power.

Moderate

Symbol

The ticker of a cryptocurrency; for example, Bitcoin's symbol is BTC.

Easy

Symmetric Boolean function

In mathematics, a symmetric Boolean function is a Boolean function whose value does not depend on the order of its input bits, i.e., it depends only on the number of ones in the input. For this reason they are also known as Boolean counting functions.

Symmetric Key Cryptography

Symmetric key cryptography is a type of cryptography that uses a single key to both encrypt and decrypt data.

Hard

Synthetic Asset

Synthetic assets, sometimes referred to as synths, are a combination of cryptocurrencies and traditional derivative assets. In other words, synths are tokenized derivatives.

Hard

T

T-Address (Zcash)

T-addresses are one of the two types of addresses available for the privacy-focused cryptocurrency, Zcash, used when transparency is desired.

Moderate

T-function

In cryptography, a T-function is a bijective mapping that updates every bit of the state in a way that can be described as , or in simple words an update function in which each bit of the state is updated by a linear combination of the same bit and a function of a subset of its less significant bits. If every single less significant bit is included in the update of every bit in the state, such a T-function is called triangular. Thanks to their bijectivity regardless of the used Boolean functions and regardless of the selection of inputs, T-functions are now widely used in cryptography to construct block ciphers, stream ciphers, PRNGs and hash functions. T-functions were first proposed in 2002 by A. Klimov and A. Shamir in their paper "A New Class of Invertible Mappings". Ciphers such as TSC-1, TSC-3, TSC-4, ABC, Mir-1 and VEST are built with different types of T-functions.

Tableau de Concordance

The Tableau de Concordance was the main French diplomatic code used during World War I; the term also refers to any message sent using the code. It was a superenciphered four-digit code that was changed three times between 1 August 1914 and 15 January 1915.

Taint

The percentage of cryptocurrency in an account that can be traced to another account.

Moderate

Take Profit

A take-profit order is an act of selling cryptocurrency to secure profits. It is usually executed at a predetermined price when the trade is in profit.

Easy

Talim (textiles)

Talim in textiles is a symbolic code and system of notation that facilitates the creation of intricate patterns in fabrics, such as shawls and carpets, and the written coded plans that include colour schemes and weaving instructions. The term is used in traditional hand-weaving in the Indian subcontinent. Talim was initially used to create certain types of patterns in Kashmiri shawls, and later came to be applied in the

Tamper-Proof Ledger

A tamper-proof ledger is essentially any system of records that has the fundamental properties of a blockchain distributed ledger.

Hard

Tamperproofing

Tamperproofing is a methodology used to hinder, deter or detect unauthorised access to a device or circumvention of a security system. Since any device or system can be foiled by a person with sufficient knowledge, equipment, and time, the term "tamperproof" is a misnomer unless some limitations on the tampering party's resources is explicit or assumed.

Tangle

The Tangle is a blockchain alternative developed by IOTA, using directed acyclic graphs which only builds in one single direction and in a way that it never repeats, and is quantum-computing resistant.

Hard

Tap-to-Earn Crypto Games

Tap-to-earn crypto games are applications that allow users to earn crypto rewards by performing simple, repetitive actions - typically tapping or clicking on their device screens.

Easy

Taproot

A Bitcoin soft fork (BIP-341) that introduced Schnorr signatures and Merklized Abstract Syntax Trees (MAST), allowing complex scripts to look like simple single-key spends when all parties cooperate. Taproot improves privacy, reduces fees for cooperative closings, and enables aggregated signatures via MuSig2. SSP's future Taproot multisig would have the same on-chain footprint as a single-key spend in the cooperative case.

Advanced

Tardigrade (Storj)

Tardigrade is the decentralized cloud storage service provided by the Storj platform.

Hard

Tcpcrypt

In computer networking, tcpcrypt is a transport layer communication encryption protocol. Unlike prior protocols like TLS (SSL), tcpcrypt is implemented as a TCP extension. It was designed by a team of six security and networking experts: Andrea Bittau, Mike Hamburg, Mark Handley, David Mazières, Dan Boneh and Quinn Slack. Tcpcrypt has been published as an Internet Draft. Experimental user-space implementations are available for Linux, Mac OS X, FreeBSD and Windows. There is also a Linux kernel implementation.

Technical Analysis/Trend Analysis (TA)

An evaluation method involving statistical analyses of market activity, such as price and volume. Charts and other tools are used to identify patterns to underpin and drive investment decisions.

Moderate

Technical Indicators

A technical indicator is a statistical algorithm or pattern-based indication based on a security's or contract's historical price, volume, and/or open interest.

Easy

Teleadministration

Teleadministration is based on the concept that documents in electronic format have legal value. Administrative informatics is not new, but for many years it was merely information technology applied to legal documents; that is, the reproduction of paper-based legal documents into electronic file systems. Instead, teleadministration turns this approach into its head. It is based on research conducted in 1978, the year when, at a conference promoted by the Court of Cassation, Giovanni Duni launched the then-futuristic idea that an electronic document could have legal value. 1978 was also the year in which the first research on digital signatures (RSA) was published in the United States, yet it would take more than twenty-five years for jurists and mathematicians to start working together.

Temporal Key Integrity Protocol

Temporal Key Integrity Protocol is a security protocol used in the IEEE 802.11 wireless networking standard. TKIP was designed by the IEEE 802.11i task group and the Wi-Fi Alliance as an interim solution to replace Wired Equivalent Privacy (WEP) without requiring the replacement of legacy hardware. This was necessary because the breaking of WEP had left Wi-Fi networks without viable link-layer security, and a solution was required for already deployed hardware. However, TKIP itself is no longer considered secure, and was deprecated in the 2012 revision of the 802.11 standard.

Tencent QQ

Tencent QQ, also known as QQ, is an instant messaging software service and web portal developed by the Chinese technology company Tencent. QQ offers services that provide online social games, music, shopping, microblogging, movies, and group and voice chat software. As of March 2023, there were 597 million monthly active QQ accounts.

Tendermint

Tendermint is a consensus mechanism that allows applications to launch across different machines securely and consistently.

Hard

Terahashes Per Second

Terahashes per second (Th/s) is equivalent to 1 trillion (1,000,000,000,000) hashes per second, a unit that indicates the power of a computer or mining machine.

Easy

TeraWulf

TeraWulf Inc. is an American bitcoin mining company. Founded in 2021 and publicly listed on Nasdaq under the ticker WULF, it operates mining facilities in New York and Pennsylvania.

Terra (blockchain)

Terra is a blockchain protocol and payment platform used for algorithmic stablecoins. The project was created in 2018 by Terraform Labs, a startup co-founded by Do Kwon and Daniel Shin. It is best known for its Terra algorithmic stablecoin and the associated LUNA reserve asset cryptocurrency.

Testnet

An alternative blockchain used by developers for testing.

Easy

Tether (cryptocurrency)

Tether, often referred to by its currency codes USD₮ and USDT, is a cryptocurrency stablecoin launched by Tether Limited Inc. in 2014. It is pegged to the United States dollar, and is distinct from a central bank digital currency (CBDC). As of 1 August 2024, Tether reported having $118.4 billion in reserves, including $5.3 billion in excess reserves. In the second quarter of 2024, the company reported a profit of $1.3 billion, contributing to a total profit of $5.2 billion for the first half of the year. Tether Limited also disclosed a net equity of $11.9 billion, and the stablecoin's market capitalization exceeded $114 billion.

Tether Limited

Tether Limited is a financial technology company that issues the Tether stablecoin (USDT), the world’s largest stablecoin by market capitalization. Founded in 2014, Tether pioneered the concept of fiat-backed digital currencies pegged 1:1 to traditional currencies. USDT has become a key source of liquidity in the cryptocurrency market, with over $170 billion in tokens circulating as of 2025. Tether Limited is privately owned and has grown into one of the most valuable fintech companies; in 2025 it was reportedly seeking to raise capital at a valuation of around $500 billion, which would place it among the world’s most valuable firms.

Texas Strategic Bitcoin Reserve

The Texas Strategic Bitcoin Reserve is a strategic reserve fund that enables the State of Texas to purchase cryptocurrency.

Tezos

Tezos is an open-source blockchain that can execute peer-to-peer transactions and serve as a platform for deploying smart contracts. The native cryptocurrency for the Tezos blockchain is the tez. The Tezos network achieves consensus using proof-of-stake. Tezos uses an on-chain governance model that enables the protocol to be amended when upgrade proposals receive a favorable vote from the community. Its testnet was launched in June 2018, and its mainnet went live in September 2018.

The Barbell Strategy

A method in which investors put their money in two extremes of high-risk and no-risk assets while ignoring the middle-risk assets.

Easy

The Bitcoin Standard

The Bitcoin Standard: The Decentralized Alternative to Central Banking is a 2018 book by Saifedean Ammous, published by Wiley.

The Block (website)

The Block is an American online publication specializing in cryptocurrencies. It is based in New York.

The Cantillon Effect

Developed by Richard Cantillon, The Cantillon Effect is a change in relative prices resulting from a change in the money supply.

Moderate

The DAO

The DAO is the first decentralized autonomous organization, which was created by a group of developers in April 2016.

Easy

The Flash (film)

The Flash is a 2023 American superhero film based on the DC Comics character Barry Allen / The Flash. Directed by Andy Muschietti from a screenplay by Christina Hodson and a story by the writing team of John Francis Daley and Jonathan Goldstein alongside Joby Harold, it is the 13th film in the DC Extended Universe (DCEU). Ezra Miller stars as Barry Allen, who travels back in time to prevent his mother's death and becomes stranded in an alternate past. Sasha Calle also stars in her film debut, alongside Michael Shannon, Ron Livingston, Maribel Verdú, Kiersey Clemons, Antje Traue, and Michael Keaton. Barbara Muschietti and Michael Disco produced the film for DC Films and Warner Bros. Pictures.

The Graph

The Graph is an open-source, decentralized protocol that powers the indexing and querying of blockchain data. It enables developers to build scalable web3 decentralized applications without managing complex indexing and querying infrastructure. It powers indexing, querying, real-time data streams, and analytics. The protocol is designed to support the growing infrastructure needs of web3, artificial intelligence (AI) agents, and dapps. With support for multiple networks, including Ethereum, Solana, Arbitrum, Base, BSC, and Polygon, The Graph is the industry standard for accessing blockchain data.

The Magic Words are Squeamish Ossifrage

"The Magic Words are Squeamish Ossifrage" was the solution to a challenge ciphertext posed by the inventors of the RSA cipher in 1977. The problem appeared in Martin Gardner's Mathematical Games column in the August 1977 issue of Scientific American. It was solved in 1993–94 by a large, joint computer project co-ordinated by Derek Atkins, Michael Graff, Arjen Lenstra and Paul Leyland. More than 600 volunteers contributed CPU time from about 1,600 machines over six months. The coordination was done via the Internet and was one of the first such projects.

The Merge (Ethereum 2.0)

The merge is a planned network upgrade that will combine the Ethereum mainnet and the Beacon Chain to transition from the proof-of-work consensus mechanism to the proof-of-stake system.

Hard

The Mysterious Mr. Nakamoto

The Mysterious Mr. Nakamoto: A Fifteen-Year Quest to Unmask the Secret Genius Behind Crypto is a 2025 book by Benjamin Wallace about Satoshi Nakamoto, the pseudonymous creator of Bitcoin, and the long-running efforts to determine Nakamoto's identity. Published by Crown on March 18, 2025, the book follows Wallace's fifteen-year investigation into Bitcoin's origins, the cypherpunk milieu from which it emerged, and the many people proposed as Nakamoto.

The Rise and Rise of Bitcoin

The Rise and Rise of Bitcoin is a 2014 American documentary film directed by Nicholas Mross. The film interviews multiple companies and people that have played important roles in the history expansion of Bitcoin. It first premiered at the Tribeca Film Festival in New York on April 23, 2014. The film was nominated for the “Best International Documentary Film” at the 2014 Zurich Film Festival. The film has a run time of 96 minutes.

Think Long Term (TLT)

A mindset where you have a longer-term investment horizon of months to years.

Moderate

This Is Gentlemen

Originally an error in writing the full “This is it, gentlemen”. It is now used as an introduction for good news.

Easy

Thodex

Koineks Teknoloji A.Ş., known online as Thodex, is a defunct Turkey-based cryptocurrency exchange founded by Faruk Fatih Özer.

Three-pass protocol

In cryptography, a three-pass protocol for sending messages is a framework which allows one party to securely send a message to a second party without the need to exchange or distribute encryption keys. Such message protocols should not be confused with various other algorithms which use 3 passes for authentication.

Threshold cryptosystem

A threshold cryptosystem, the basis for the field of threshold cryptography, is a cryptosystem in which the secret key is split into a number of pieces that are given to different parties. Several parties can then cooperate to use the cryptosystem.

Threshold Signature

A cryptographic scheme where a signing key is distributed among N parties and any M of them can produce a valid signature without any single party knowing the full key. Unlike script-based multisig, a threshold signature produces a single on-chain signature that reveals nothing about the signing structure. FROST and MuSig2 are threshold signature protocols applicable to Schnorr-based chains.

Advanced

Throughput

Throughput is how many actions can be completed in a given time frame.

Moderate

Ticker

An abbreviation used to uniquely identify cryptocurrencies. *see Symbol.

Easy

Ticker Symbol

The ticker symbol is the unique combination of letters assigned to stocks or cryptocurrencies that makes them distinguishable on exchanges and other trading applications.

Moderate

Tiger (hash function)

In cryptography, Tiger is a cryptographic hash function designed by Ross Anderson and Eli Biham in 1995 for efficiency on 64-bit platforms. The size of a Tiger hash value is 192 bits. Truncated versions can be used for compatibility with protocols assuming a particular hash size. Unlike the SHA-2 family, no distinguishing initialization values are defined; they are simply prefixes of the full Tiger/192 hash value.

Time stamp protocol

The Time-Stamp Protocol, or TSP is a cryptographic protocol for certifying timestamps using X.509 certificates and public key infrastructure. The timestamp is the signer's assertion that a piece of electronic data existed at or before a particular time. The protocol is defined in RFC 3161. One application of the protocol is to show that a digital signature was issued before a point in time, for example before the corresponding certificate was revoked.

The process by which real-world assets are turned into something of digital value called a token, often subsequently able to offer ownership of parts of this asset to different owners.

Moderate

Tokenization (data security)

Tokenization, when applied to data security, is the process of substituting a sensitive data element with a non-sensitive equivalent, referred to as a token, that has no intrinsic or exploitable meaning or value. The token is a reference that maps back to the sensitive data through a tokenization system. The mapping from original data to a token uses methods that render tokens infeasible to reverse in the absence of the tokenization system, for example using tokens created from random numbers. A one-way cryptographic function is used to convert the original data into tokens, making it difficult to recreate the original data without obtaining entry to the tokenization system's resources. To deliver such services, the system maintains a vault database of tokens that are connected to the corresponding sensitive data. Protecting the system vault is vital to the system, and improved processes must be put in place to offer database integrity and physical security.

Tokenized Carbon Credits

Tokenized carbon credits represent carbon that has been avoided or removed from the environment. One metric tonne of carbon verifiably avoided or removed translates to one carbon credit.

Moderate

Tokenized Identity

Tokenized identity refers to the representation of an identity as a digital token on a blockchain, enabling seamless, interoperable identity verification across platforms and applications.

Easy

Tokenized private placement

A tokenized private placement is a form of digital securities offering that combines traditional private placement structures with blockchain technology to create tradeable digital tokens representing ownership stakes in private companies or assets. This emerging financial technology allows companies, particularly small and medium-sized enterprises (SMEs), to raise capital while providing investors with potentially greater liquidity compared to conventional private placements.

Tokenized real-world asset

Real-World Asset or RWA is an asset class within blockchain and cryptocurrency that represents a digital token of a tangible or intangible asset existing outside the blockchain ecosystem. These tokens are created through a process called tokenization, which aims to bridge the gap between traditional finance (TradFi) and decentralized finance (DeFi). RWAs can represent a wide range of assets, such as real estate, government and corporate bonds, commodities like gold, private credit, and works of art. This asset class is considered a key driver of digital asset adoption, with some financial leaders, such as BlackRock CEO Larry Fink, describing the underlying technology as "the next generation for markets." The asset class has garnered significant attention from financial regulators, with bodies such as the U.S. President's Working Group on Digital Asset Markets outlining frameworks for its integration into national financial systems.

Tokenized Securities

Tokenized securities are when the ownership of a security is materialized through the issuance of a token.

Moderate

Tokenized Stocks

Tokenized Stocks are the digital assets that are traded on exchanges using blockchain technology.

Easy

Tokenomics

Tokenomics is the science of token economy which consists of a set of rules that governs a cryptocurrency's issuance and supply.

Easy

TokenSets (Set Protocol)

TokenSets is a Set Protocol-based decentralized platform for crypto portfolio management.

Hard

Tokken

Tokken is a payment system and mobile app most known for being a legal and secure option for businesses transactions within the cannabis industry, because of its compliance with bank requirements. The startup company was created by Lamine Zarrad, a former regulator at the Office of the Comptroller of the Currency.

Toll Bridge

A toll bridge is a bridge powered by a smart contract where a monetary value called a toll fee unlocks access to extra functionalities.

Moderate

TON (blockchain)

The Open Network (TON), or simply TON Blockchain, is a public, decentralised layer-1 blockchain platform that employs the cryptocurrency Toncoin to support transactions and its decentralised-app ecosystem. TON was originally established by Nikolai Durov, who co-founded the Telegram messaging platform, and was originally explored in a technical white paper publication released in 2019. After a legal dispute with the U.S. Securities and Exchange Commission (SEC) caused Telegram to abandon the project in 2020, the application has subsequently been developed and governed by an independent, community-run body called the TON Foundation.

Tor

Tor is a decentralized network that anonymizes users' web traffic by encrypting it and routing it through a series of relays before it reaches its final destination.

Easy

Tornado Cash

Tornado Cash is an open source, non-custodial, fully decentralized cryptocurrency tumbler that runs on Ethereum Virtual Machine-compatible networks. It offers a service that mixes potentially identifiable or "tainted" cryptocurrency funds with others, so as to obscure the trail back to the fund's original source. This is a privacy tool used in EVM networks where all transactions are public by default.

Torus-based cryptography

Torus-based cryptography involves using algebraic tori to construct a group for use in ciphers based on the discrete logarithm problem. This idea was first introduced by Alice Silverberg and Karl Rubin in 2003 in the form of a public key algorithm by the name of CEILIDH. It improves on conventional cryptosystems by representing some elements of large finite fields compactly and therefore transmitting fewer bits.

Total Exchange Volume

Total exchange volume is a measure of the total value that has been traded on an exchange(s).

Easy

Total Supply

The total amount of coins in existence right now, minus any coins that have been verifiably burned. *see Circulating Supply and Max Supply.

Easy

Total Value Locked (TVL)

Тotal value locked represents the number of assets that are currently being staked in a specific protocol.

Easy

A transaction ID (TXID) is the unique identification number of each blockchain transaction.

Easy

Transaction malleability problem

The transaction malleability problem is a vulnerability in blockchain which can be exploited by altering a cryptographic hash, such as the digital signature used to identify a cryptocurrency transaction. Transaction malleability is considered to be one of the largest ongoing threats to blockchain technology, as it can compromise financial transactions such as Bitcoin and other cryptocurrency transactions, and cause other issues in the network.

Transaction Triggers

Triggers can be set up on a blockchain, which group various transactions together to be executed when the designated conditions are met.

Hard

Transactions Per Second (TPS)

Transactions per second (TPS) is a measure of a computer system's (or network's) capacity to perform transactions or calculations in a second.

Easy

Transient-key cryptography

Transient-key cryptography is a form of public-key cryptography wherein keypairs are generated and assigned to brief intervals of time instead of to individuals or organizations, and the blocks of cryptographic data are chained through time. In a transient-key system, private keys are used briefly and then destroyed, which is why it is sometimes nicknamed “disposable crypto.” Data encrypted with a private key associated with a specific time interval can be irrefutably linked to that interval, making transient-key cryptography particularly useful for digital trusted timestamping. Transient-key cryptography was invented in 1997 by Michael Doyle of Eolas, and has been adopted in the ANSI ASC X9.95 Standard for trusted timestamps.

Transmission security

Transmission security (TRANSEC) is the component of communications security (COMSEC) that results from the application of measures designed to protect transmissions from interception and exploitation by means other than cryptanalysis. Goals of transmission security include:Low probability of interception (LPI) Low probability of detection (LPD) Antijam — resistance to jamming (EPM or ECCM)

Transparent decryption

Transparent decryption is a method of decrypting data which unavoidably produces evidence that the decryption operation has taken place. The idea is to prevent the covert decryption of data. In particular, transparent decryption protocols allow a user Alice to share with Bob the right to access data, in such a way that Bob may decrypt at a time of his choosing, but only while simultaneously leaving evidence for Alice of the fact that decryption occurred. Transparent decryption supports privacy, because this evidence alerts data subjects to the fact that information about them has been decrypted and disincentivises data misuse.

Transport Layer Security

Transport Layer Security (TLS) is a cryptographic protocol designed to provide communications security over a computer network, such as the Internet. The protocol is widely used in applications such as email, instant messaging, and voice over IP, but its use in securing HTTPS remains the most publicly visible.

Trapdoor function

In theoretical computer science and cryptography, a trapdoor function is a function that is easy to compute in one direction, yet difficult to compute in the opposite direction without special information, called the "trapdoor". Trapdoor functions are a special case of one-way functions and are widely used in public-key cryptography.

TRC-10 (TRON)

TRC10 is a technological token standard that does not require the TRON Virtual Machine and is backed by the TRON blockchain network (TVM).

Moderate

TRC-20 Token

The TRC-20 token standard allows for tokens to be created on the TRON network.

Moderate

Treasury Bills (T-Bills)

Treasury bills (T-Bills) are short-term U.S. government debt obligations.

Easy

Treasury Bond (T-Bond)

The treasury bond is a debt security issued by the United States government that is backed by the "full faith and credit" of the U.S. Treasury Department.

Easy

Trust Wallet

Trust Wallet is a crypto wallet software that gives its users complete ownership of their crypto funds.

Easy

Trusted Computing

Trusted Computing (TC) is a technology developed and promoted by the Trusted Computing Group. The term is taken from the field of trusted systems and has a specialized meaning that is distinct from the field of confidential computing. With Trusted Computing, the computer will consistently behave in expected ways, and those behaviors will be enforced by computer hardware and software. Enforcing this behavior is achieved by loading the hardware with a unique encryption key that is inaccessible to the rest of the system and the owner.

Trusted Execution Environments (TEEs)

Trusted Execution Environments (TEEs) are secure areas within a main processor that provide a protected space where sensitive code and data can operate without fear of tampering or observation from the outside world.

Hard

Trusted third party

In cryptography, a trusted third party (TTP) is an entity which facilitates interactions between two parties who both trust the third party; the third party reviews all critical transaction communications between the parties, based on the ease of creating fraudulent digital content. In TTP models, the relying parties use this trust to secure their own interactions. TTPs are common in any number of commercial transactions and in cryptographic digital transactions as well as cryptographic protocols, for example, a certificate authority (CA) would issue a digital certificate to one of the two parties in the next example. The CA then becomes the TTP to that certificate's issuance. Likewise transactions that need a third party recordation would also need a third-party repository service of some kind.

Trustless

An environment where there is no centralized authority.

Moderate

A physically unclonable function (PUF) is a physical entity that can serve as a hardware security primitive, particularly useful in authentication and anti-counterfeiting applications. PUFs generate identifiers based on unique, complex physical structures or responses that are difficult to replicate or model. Their evaluation typically involves measuring physical properties or optical features associated with the specific device.

TypeScript Programming Language

TypeScript programming language is a more advanced version of JavaScript that includes more functionality.

Moderate

Typosquatting

Typosquatting is a deceptive practice used by scammers to trick people into entering a counterfeit website and compromising their private information.

Easy

U

U-Prove

U-Prove is a free and open-source technology and accompanying software development kit for user-centric identity management. The underlying cryptographic protocols were designed by Dr. Stefan Brands and further developed by Credentica and, subsequently, Microsoft. The technology was developed to allow internet users to disclose only the minimum amount of personal data when making electronic transactions as a way to reduce the likelihood of privacy violations.

U.S. Strategic Bitcoin Reserve

The Strategic Bitcoin Reserve is a proposed reserve asset, funded by the United States Department of the Treasury's forfeited bitcoin, announced by United States president Donald Trump in March 2025. The United States Digital Asset Stockpile for non-bitcoin assets was also announced to be created. Trump has previously stated that he wants the United States to become the "crypto capital of the world".

Ultra (cryptography)

Ultra was the designation adopted by British military intelligence in June 1941 for wartime signals intelligence obtained by breaking high-level encrypted enemy radio and teleprinter communications at the Government Code and Cypher School (GC&CS) at Bletchley Park. Ultra eventually became the standard designation among the western Allies for all such intelligence. The name arose because the intelligence obtained was considered more important than that designated by the highest British security classification then used and so was regarded as being Ultra Secret. Several other cryptonyms had been used for such intelligence.

Unbanked

Unbanked refers to those that are either unable to access banking services, or choose not to.

Easy

Uncle Block (Ommer Block)

Uncle Block (Ommer Block) refers to the discarded block in the phenomenon when two blocks are simultaneously created, resulting in one block being omitted from the blockchain.

Moderate

Unconfirmed

A state in which a transaction has not been appended to the blockchain.

Moderate

Undeniable signature

An undeniable signature is a digital signature scheme which allows the signer to be selective to whom they allow to verify signatures. The scheme adds explicit signature repudiation, preventing a signer later refusing to verify a signature by omission; a situation that would devalue the signature in the eyes of the verifier. It was invented by David Chaum and Hans van Antwerpen in 1989.

UNI Token

A native governance token of Uniswap, the largest decentralized exchange at the time of writing.

Easy

Uniswap

Uniswap is a decentralized cryptocurrency exchange protocol built on the Ethereum blockchain. It enables the automated trading of digital assets through smart contracts, eliminating the need for intermediaries or centralized order books. Uniswap facilitates cryptocurrency tokens swaps using liquidity pools contributed by users.

Unit of Account

A unit of account is a standardized unit of measurement used in accounting to record and track financial transactions.

Easy

United States House Committee on Financial Services

The U.S. House Committee on Financial Services is a committee of the United States House of Representatives that oversees all components of the US’s financial and housing services.

Easy

United States v. Gratkowski

United States v. Gratkowski, 964 F.3d 307, was a case in the United States Court of Appeals for the Fifth Circuit involving the Fourth Amendment implications of Bitcoin transactions.

Universal hashing

In mathematics and computing, universal hashing refers to selecting a hash function at random from a family of hash functions with a certain mathematical property. This guarantees a low number of collisions in expectation, even if the data is chosen by an adversary. Many universal families are known, and their evaluation is often very efficient. Universal hashing has numerous uses in computer science, for example in implementations of hash tables, randomized algorithms, and cryptography.

Upbit is a South Korean cryptocurrency exchange founded in 2017. It is operated by Dunamu, which is one of the highest-valued startups in South Korea.

Urbit

Urbit is a decentralized personal server platform based on functional programming in a peer-to-peer network.

US Office of Foreign Assets Control (OFAC)

The US Office of Foreign Assets Control (OFAC) is a financial intelligence and enforcement agency of the US Treasury Department.

Easy

USDC (cryptocurrency)

USDC is a cryptocurrency stablecoin issued by Circle Internet Group. It is pegged to the United States dollar, and is distinct from a central bank digital currency (CBDC).

Use Case

A use case is a description of the interactions between an actor (human or system) and a system that leads to an event.

Easy

User Interface

The user interface is the user’s interaction with a website or application using a digital device.

Easy

User Operation

The ERC-4337 equivalent of a standard Ethereum transaction for smart-contract wallets — a data structure containing the sender, call data, gas limits, nonce, signature, and optional paymaster fields. UserOperations are submitted to an alternative mempool and bundled into regular on-chain transactions by bundlers. They enable features impossible for EOAs, such as batched calls, sponsored gas, and custom signature validation.

Advanced

UTC Time

Coordinated Universal Time.

Easy

Utility Mining

Utility mining is a mechanism that allows for the distribution of tokens based on user activity and active participation. This allows crypto projects to distribute flexible yields attached to any specified on-chain interaction.

Hard

Utility Token

Tokens that are designed specifically to be able to help people use something.

A cryptocurrency public address with custom letters and numbers, usually picked by its owner.

Moderate

Vaporware

A cryptocurrency project that is never actually developed.

Moderate

Ven (currency)

Ven is a private digital accounting unit and internal credit system issued by Hub Culture Ltd. Launched in 2007 by promoter Stan Stalnaker, the unit is presented as a representative money system for the Hub Culture social network. The company claims Ven's value is derived from a proprietary, weighted basket of fiat currencies, commodities, and carbon credits; however, as the ledger is centralized and closed to public audit, there is no independent verification of these reserves. While marketed as the "first digital currency" to trade in regulated Forex markets, it lacks liquidity on major public exchanges and primarily functions as an internal medium of exchange.

Venture Capital

A form of private equity provided to fund small, early-stage firms considered to have high growth potential.

Easy

Verge (cryptocurrency)

Verge Currency is a decentralized open-source cryptocurrency which offers various levels of private transactions. It does this by obfuscating the IP addresses of users with Tor and by leveraging stealth transactions making it difficult to determine the geolocation of its users.

Verifiable random function

In cryptography, a verifiable random function (VRF) is a public-key pseudorandom function that provides proofs that its outputs were calculated correctly. The owner of the secret key can compute the function value as well as an associated proof for any input value. Everyone else, using the proof and the associated public key, can check that this value was indeed calculated correctly, yet this information cannot be used to find the secret key.

Verification Code

A verification code is a security protection method that is used to avoid internet bots from abusing or even spamming various online services.

Moderate

Vertcoin

Vertcoin is an open-source cryptocurrency created in early 2014, that focuses on decentralization. Vertcoin uses a proof-of-work mechanism to issue new coins and incentivize miners to secure the network and validate transactions. Vertcoin is designed to be mined via graphics cards instead of through ASICs.

Very smooth hash

In cryptography, Very Smooth Hash (VSH) is a provably secure cryptographic hash function invented in 2005 by Scott Contini, Arjen Lenstra, and Ron Steinfeld. Provably secure means that finding collisions is as difficult as some known hard mathematical problem. Unlike other provably secure collision-resistant hashes, VSH is efficient and usable in practice. Asymptotically, it only requires a single multiplication per log(n) message-bits and uses RSA-type arithmetic. Therefore, VSH can be useful in embedded environments where code space is limited.

VEST

VEST (Very Efficient Substitution Transposition) ciphers are a set of families of general-purpose hardware-dedicated ciphers that support single pass authenticated encryption and can operate as collision-resistant hash functions designed by Sean O'Neil, Benjamin Gittins and Howard Landman. VEST cannot be implemented efficiently in software.

Vesting Period

The act of restricting the sale of a token for a particular period of time.

Easy

VeVe

VeVe is a New Zealand-based company specializing in licensed digital collectibles. The company has mobile apps available for Android and iOS devices, as well as a web app, where users can purchase digital collectibles and view them in AR & VR. VeVe has the distinction of being the first marketplace to offer NFTs from prominent brands such as Marvel, Disney and DC.

Virgin Bitcoin

A Bitcoin that has never been spent.

Moderate

Virtual Automated Market Makers (vAMMs)

A virtual Automated Market Maker (vAMM) is a system that provides synthetic (or virtual) liquidity, allowing traders to buy and sell derivatives entirely on the blockchain.

Hard

Virtual Commodity Association (VCA)

The virtual commodity association is a non-profit organization of cryptocurrency exchanges and custodians with an aim to build a self-regulatory organization (SRO) for the U.S. virtual currency industry.

Moderate

Virtual currency law in Iran

In 2018, Iran recognized cryptocurrency mining as a legal industry in order to monitor and regulate the mining farms that were already operating. In December 2025 Iranian regime globally banned any and all transaction and transfer of cryptocurrency and along with that of in gold. In July 2018, President Hassan Rouhani's administration declared its intention of launching a national cryptocurrency, a news agency affiliated with the Central Bank of Iran outlined multiple features of the national cryptocurrency, stating that it would be backed by the Iran's national currency, the rial. The cryptocurrency could allow Iranians to make international transactions amidst trade embargo. As of December 2020 Iranians traded between $16 and $20 million in 12 different cryptocurrencies each day. Iran's mining amount of bitcoin is close to $1 billion a year.

Virtual Private Network (VPN)

A virtual private network (VPN) is a technology that creates a safe and encrypted network from a public internet connection – giving you anonymity and privacy.

Easy

Virtual Reality (VR)

Virtual reality (VR) technology is used to simulate an immersive artificial world that can mimic or transcend reality. V

Easy

Virus

Computers are usually infected with a virus when a user unknowingly installs it via a downloaded file.

Easy

Visible Embryo Project

The Visible Embryo Project (VEP) is a multi-institutional, multidisciplinary research project originally created in the early 1990s as a collaboration between the Developmental Anatomy Center at the National Museum of Health and Medicine and the Biomedical Visualization Laboratory (BVL) at the University of Illinois at Chicago, "to develop software strategies for the development of distributed biostructural databases using cutting-edge technologies for high-performance computing and communications (HPCC), and to implement these tools in the creation of a large-scale digital archive of multidimensional data on normal and abnormal human development." This project related to BVL's other research in the areas of health informatics, educational multimedia, and biomedical imaging science. Over the following decades, the list of VEP collaborators grew to include over a dozen universities, national laboratories, and companies around the world.

Visual cryptography

Visual cryptography is a cryptographic technique which allows visual information to be encrypted in such a way that the decrypted information appears as a visual image.

Vitalik Buterin

Vitalik Buterin is one of the creators of Ethereum, the second-largest cryptocurrency after Bitcoin.

Easy

Vndc

VNDC is a stablecoin that’s claimed to be pegged 1:1 to the Vietnamese đồng. It has been widely adopted by the Vietnamese cryptocurrency community for trading and transactions.

Voice inversion

Voice inversion scrambling is an analog method of obscuring the content of a transmission. It is sometimes used in public service radio, automobile racing, cordless telephones and the Family Radio Service. Without a descrambler, the transmission makes the speaker "sound like Donald Duck". Despite the term, the technique operates on the passband of the information and so can be applied to any information being transmitted.

Voiceverse NFT plagiarism scandal

Easy

Web 3.0 is the coming generation of the internet.

Moderate

Web3

Web3 is an idea for a new iteration of the World Wide Web which incorporates concepts such as decentralization, blockchain technologies, tokenomics, and privacy-enhancing technologies. The term is sometimes confused with the Semantic Web, as both have sometimes been referred to as "Web 3.0". Some technologists and journalists have contrasted it with Web 2.0, in which they say user-generated content is controlled by a small group of companies referred to as Big Tech. The term "web 3.0" as applied to blockchain technology was coined in 2014 by Ethereum co-founder Gavin Wood, and the idea gained interest in 2021 from cryptocurrency enthusiasts, large technology companies, and venture capital firms.

Web3 Foundation

The Web3 Foundation was created to foster new technologies and applications in the field of decentralized web software protocols.

Easy

Wi‑Fi Protected Setup (WPS), referred to as Wi‑Fi Simple Configuration in the specification, and branded as WPS, is a standard designed to ease the setup of Wi‑Fi networks in home and small office environments.

Winding Down

Winding down is the process of unwrapping tokens back to their original form in DeFi.

Moderate

Winding Up

In decentralized finance (DeFi), winding up essentially means wrapping crypto tokens through various projects in order to find the best yield.

Moderate

Wired Equivalent Privacy

Wired Equivalent Privacy (WEP) is an obsolete security algorithm for 802.11 wireless networks. It was introduced as part of the original IEEE 802.11 standard ratified in 1997. The intention was to provide a level of security and privacy comparable to that of a traditional wired network. WEP, recognizable by its key of 10 or 26 hexadecimal digits, was at one time widely used, and was often the first security choice presented to users by router configuration tools. After a severe design flaw in the algorithm was disclosed in 2001, WEP was no longer considered a secure method of wireless connection; however, in the vast majority of cases, Wi-Fi hardware devices relying on WEP security could not be upgraded to secure operation. Some of WEP's design flaws were addressed in WEP2, but it also proved insecure, and never saw wide adoption or standardization.

Wireless Public Key Infrastructure

Wireless Public Key Infrastructure (WPKI) is a technology that provides public key infrastructure functionality using a mobile Secure Element such as a SIM card. It can be used for example for two-factor authentication.

Wireless Transport Layer Security

Wireless Transport Layer Security (WTLS) is a security protocol, part of the Wireless Application Protocol (WAP) stack. It sits between the WTP and WDP layers in the WAP communications stack.

WLAN Authentication and Privacy Infrastructure

WLAN Authentication and Privacy Infrastructure (WAPI) is a Chinese National Standard for Wireless LANs . Although it was allegedly designed to operate on top of Wi-Fi, compatibility with the security protocol used by the 802.11 wireless networking standard developed by the IEEE is in dispute. Due to the limited access of the standard, it was the focus of a U.S.–China trade dispute. Following this it was submitted to, and rejected by the ISO. It was resubmitted to ISO in 2010, but was cancelled as a project on 21 November 2011 after being withdrawn by China.

World (blockchain)

World, also known as World Network, is a humanity verification project and financial network. It was developed and launched as the cryptocurrency project Worldcoin. Among other organizations, contributors to the project include Tools for Humanity, a company founded in 2019 by Sam Altman, Max Novendstern, and Alex Blania. World's stated mission is to provide a reliable and anonymous way to authenticate humans online, which it calls World ID. After accumulating $250 million in funding from venture capital firms such as Andreessen Horowitz, it launched out of beta in 2023. The project was rebranded as World in 2024, at which point it had partnerships with the governments of Taiwan and Malaysia concerning digital identity verification. To join the network, new users complete biometric verification by the company's Orb hardware, with users in some locales then receiving Worldcoin (WLD), a digital token. This collection process has caused privacy concerns in multiple countries.

World Liberty Financial

World Liberty Financial (WLFI) is a decentralized finance protocol developed by its namesake company. It was founded in 2024 by Zachary Folkman, Chase Herro, Alex Witkoff, Zach Witkoff, and Trump family members. It is a business venture of the Trump family. The Trump family receives 75% of net proceeds when WLFI sells tokens, as well as gets a cut of stablecoin profits. By December 2025, the Trumps had profited $1 billion on proceeds, while holding $3 billion worth of unsold tokens.

WYSIWYS

In cryptography, What You See Is What You Sign (WYSIWYS) is a property of digital signature systems that ensures the semantic content of signed messages can not be changed, either by accident or intent.

X

X.1035

ITU-T Recommendation X.1035 specifies a password-authenticated key agreement protocol that ensures mutual authentication of two parties by using a Diffie–Hellman key exchange to establish a symmetric cryptographic key. The use of Diffie-Hellman exchange ensures perfect forward secrecy—a property of a key establishment protocol that guarantees that compromise of a session key or long-term private key after a given session does not cause the compromise of any earlier session.

X.509

In cryptography, X.509 is an International Telecommunication Union (ITU) standard defining the format of public key certificates. X.509 certificates are used in many Internet protocols, including TLS/SSL, which is the basis for HTTPS, the secure protocol for browsing the web. They are also used in offline applications, like electronic signatures.

X402

x402 is an open, neutral payment standard for internet-native transactions built on the HTTP protocol. It repurposes the long-unused HTTP 402 "Payment Required" status code to enable peer-to-peer payments directly within HTTP request-response cycles. Payments can be made in supported cryptocurrencies like USDC and through supported fiat money facilitators like payment cards.

x86 Virtual Machine (Qtum)

X86 Virtual Machine enables Qtum developers to write smart contracts in a language of their choice.

Hard

XBT

XBT is the lesser-known ticker symbol for Bitcoin.

Easy

XCOPY (artist)

XCOPY is the pseudonym of an anonymous, London-based digital artist associated with crypto art and non-fungible tokens (NFTs). Fortune described XCOPY as one of the early artists in the cryptoart field and wrote that their "static-saturated" works usually flash frantically and address death and dystopia. Sotheby's has described their animated GIFs as recognisable for dark, punk-influenced themes, distorted loops and glitch effects.

XKMS

XML Key Management Specification (XKMS) uses the web services framework to make it easier for developers to secure inter-application communication using public key infrastructure (PKI). XML Key Management Specification is a protocol developed by W3C which describes the distribution and registration of public keys. Services can access an XKMS compliant server in order to receive updated key information for encryption and authentication.

XRP Ledger

The XRP Ledger (XRPL), also called the Ripple Protocol, is a cryptocurrency platform launched in 2012 by Ripple Labs. The XRPL employs the native cryptocurrency known as XRP, and supports tokens, cryptocurrency or other units of value such as frequent flyer miles or mobile minutes.

XUDA

XUDA is a library that is used and integrated in many public key infrastructure (PKI) products of different vendors like the KEON CA of RSA LABS.

Y

Yahalom (protocol)

Yahalom is an authentication and secure key-sharing protocol designed for use on an insecure network such as the Internet. Yahalom uses a trusted arbitrator to distribute a shared key between two people. This protocol can be considered as an improved version of Wide Mouth Frog protocol, but less secure than the Needham–Schroeder protocol.

YAK (cryptography)

The YAK is a public-key authenticated key-agreement protocol, proposed by Feng Hao in 2010. It is claimed to be the simplest authenticated key exchange protocol among the related schemes, including MQV, HMQV, Station-to-Station protocol, SSL/TLS etc. The authentication is based on public key pairs. As with other protocols, YAK normally requires a Public Key Infrastructure to distribute authentic public keys to the communicating parties. The security of YAK is disputed.

Yao's test

In cryptography and the theory of computation, Yao's test is a test defined by Andrew Chi-Chih Yao in 1982, against pseudo-random sequences. A sequence of words passes Yao's test if an attacker with reasonable computational power cannot distinguish it from a sequence generated uniformly at random.

Yescrypt

In cryptography, a zero-knowledge proof enables one party to provide evidence that a transaction or event happened without revealing private details of that transaction or event.

Hard

ZRTP is a cryptographic key-agreement protocol to negotiate the keys for encryption between two end points in a Voice over IP (VoIP) phone telephony call based on the Real-time Transport Protocol. It uses Diffie–Hellman key exchange and the Secure Real-time Transport Protocol (SRTP) for encryption. ZRTP was developed by Phil Zimmermann, with help from Bryce Wilcox-O'Hearn, Colin Plumb, Jon Callas and Alan Johnston and was submitted to the Internet Engineering Task Force (IETF) by Zimmermann, Callas and Johnston on March 5, 2006, and published on April 11, 2011, as RFC 6189.