Physical unclonable function

In computing and cryptography, a physical unclonable function or PUF is a physical object whose operation cannot be reproduced ("cloned") in a physical way (by making another system using the same technology), such 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. The term is also commonly expanded as a physically unclonable function in the academic literature.