NoCiPUF: NoC-Based Intrinsic PUF for MPSoC Authentication

Modern Multi-Processor-Systems-on-Chips (MPSoCs) use Network-on-Chips (NoCs) as a scalable and efficient communication fabric. The applications running on these devices rely on frequent communication with central database servers, which are vulnerable to impersonation attacks by adversarial clones. We propose NoCiPUF, a novel NoC-based intrinsic Physically-Unclonable-Function (PUF) framework for MPSoCs authentication. We re-use the circuit switched nature of NoC with path-pairs as challenges to obtain secret responses, collectively called challenge-response-pairs (CRPs). Due to the random nature of manufacturing variations, equal hop paths exhibit unequal delays. We leverage the delay differences of flits traversing in equal-hop paths to generate unique responses. NoCiPUF is fully-synthesizable and readily scalable as it requires changes only at the behavioral level. To counter Machine-Learning (ML)-based modeling attacks on PUFs, we provide a comprehensive technique and reduce the prediction accuracy to ~52%. NoCiPUF framework incurs low area (0.76%) and power (1.14%) overheads and has no impact on NoC performance in normal mode due to independent authentication mode. Obtained responses have near-ideal PUF metrics and are verified against the NIST randomness test suite. This scheme offers high number of CRPs in larger NoC networks (>0.74 million CRPs in $5 \times 5$ mesh), proving its scalability.