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.