14.3 15fJ/b static physically unclonable functions for secure chip identification with <2% native bit instability and 140× Inter/Intra PUF hamming distance separation in 65nm

Physically unclonable functions (PUFs) enable information security down to the chip level [1-4]. Arrays of PUF bitcells (Fig. 14.3.1) generate chip-specific keys that are unpredictable, repeatable and cannot be measured externally, thus uniquely identifying the die to counteract chip piracy/counterfeiting and enable lightweight authentication/encryption [1-4]. In silicon PUFs, trustworthy bit generation is achieved by accentuating local process variations through various circuit principles (e.g., delay mismatch) and rejecting global process/voltage/temperature (PVT) variations, layout-dependent process variations and noise [2].