Bistable Physically Unclonable Function with Dynamic Threshold Voltage

The Physically Unclonable Function (PUF) is a crucial security module within the System on Chip (SoC) architecture. Essentially, PUF serves as the unique identifier of SoC taking advantage of CMOS fabrication variations. This study introduces a novel approach called Dynamic Threshold Voltage (Vt) bistable PUF (DVT PUF), offering superior randomness compared to conventional bistable PUFs like SRAM. The innovation lies in replacing conventional bistable PUF gates with a dynamic Vt Schmitt gate, such as Schmitt NAND/NOR, thereby facilitating the utilization of an advanced Challenge-Response Pair (CRP). Unlike traditional bistable PUFs employing reset (RST) as the challenge to trigger metastability, the proposed method adjusts the Schmitt gate's hysteresis based on input challenges from a Host, augmenting randomness beyond CMOS fabrication variations. This enhancement results in a 33% improvement in the Hamming Weight (HW) of the PUF compared to traditional bistable PUFs.