A 0.1-pJ/b and ACF <0.04 Multiple-Valued PUF for Chip Identification Using Bit-Line Sharing Strategy in 65-nm CMOS

Emerging physical unclonable function (PUF) circuit designs in the IC supply chain pose not only a challenge to security threats but also a serious concern about hardware efficiency. The existing conventional PUF methods extract intrinsic random physical variation to generate two-valued secret key bits, which lack logical complexity and have poor efficiency in interconnect lines. This paper proposes a multiple-valued logic PUF circuit (MPUF), which focuses on adding logical complexity and minimizing hardware cost by processing on multilevel-cell and interconnect lines. The twins' cell is selected as the MPUF cell to source the multiple-valued physical variation, and the bit-line sharing strategy was integrated to implement the four-valued PUF data. After full-custom designing, the MPUF with 512 cells only needs 16 transmit bit lines. The proposed MPUF chip is fabricated under 65-nm CMOS technology and the core area occupies approximately 0.016 mm
²
with a 4.9-μm
²
bitcell size. The measured results show that the MPUF data passed National Institute of Standards and Technology randomness tests, and that it operates 0.1-pJ/b energy efficiency at 1.2 V, ensures randomness and uniqueness with 50.42% hamming distance, and less than 0.04 autocorrelation at 95% confidence level. Compared with other state of the arts, logical complexity improves 50% for resisting power attacks.