SuperPUF: Integrating heterogeneous Physically Unclonable Functions

Physically Unclonable Functions (PUFs) combat counterfeit ICs by identifying each chip using inherent process variation. PUFs must produce sufficiently many bits, but replicating the same PUF design requires care since process variation and its spatial correlation may change in the next 10 years. Additional challenges arise in system-on-chip and heterogeneous 3D integration of diverse PUFs. Responding to these challenges, we introduce methods for combining PUFs, with provisions for sampling process variation throughout the IC. When multiple sources of entropy are available, our optimization algorithms select sources to maximize joint entropy and minimize physical overhead. Empirical validation uses SPICE simulations for a 45nm technology node.