A 2.17-pJ/b 5b-Response Attack-Resistant Strong PUF with Enhanced Statistical Performance

This article presents a Strong physically unclonable function (PUF) with a 5-bit response output, which alleviates the critical issue of huge challenge-response pair (CRP) consumption for one authentication. Attack resistance is enhanced not only by improving the substitution-permutation network (SPN) using variable secret look-up tables (LUTs) and a complex permutation XOR box but also by mitigating LUT data collision and coupling Strong PUF functions between adjacent operation rounds to protect an individual round from attack. As a result, response bitstreams pass all NIST SP800-22 randomness tests even using highly correlated challenge inputs, and mainstream modeling attacks with up to 200-Mb training samples cannot achieve higher accuracy than random guess. An automatic data write-back circuit allows the PUF to be fully stabilized by hot carrier injection (HCI) burn-in without exposing sensitive LUT data. The architecture realizes a 1-cycle/round operation and results in 2.17 pJ/b energy and 0.625 bit/cycle throughput.