METAPUF a challenge response pair generator

Abstract

Physically unclonable function (PUF) is a hardware security module preferred for hardware feature based random number and secret key generation. Security of a cryptographic system relies on the quality of the challenge-response pair, it is necessary that the key generation mechanism must unpredictable and its response should constant under different operating condition. Metastable state in CMOS latch is undesirable since it response becomes unpredictable, this feature used in this work to generate a unique response. A feedback mechanism is developed which forces the latch into the metastable region; after metastable state, latch settle to high or state depends on circuit internal condition and noise which cannot be predicted. Obtained inter hamming variation for 8 PUF is 51.43% and average intra hamming distance is 99.76% with supply voltage variation and 96.22% with temperature variation.