A Self-Regulated and Reconfigurable CMOS Physically Unclonable Function Featuring Zero-Overhead Stabilization

TL;DR

This paper introduces a reconfigurable, self-regulated CMOS PUF with zero-overhead stabilization, achieving ultra-low error rates, high stability across temperature and voltage variations, and excellent randomness and uniqueness properties.

Contribution

It presents a novel reconfigurable PUF design with zero-overhead stabilization and highly stable, low-error performance across wide temperature and voltage ranges.

Findings

Achieves 0.00182% native BER after reconfiguration.

Maintains stability with 0.12%/10°C and 0.057%/0.1V BER across wide ranges.

Exhibits excellent randomness and uniqueness, passing standard tests.

Abstract

This article presents a reconfigurable physically unclonable function (PUF) design fabricated using 65-nm CMOS technology. A subthreshold-inverter-based static PUF cell achieves 0.3% native bit error rate (BER) at 0.062-fJ per bit core energy efficiency. A flexible, native transistor-based voltage regulation scheme achieves low-overhead supply regulation with 6-mV/V line sensitivity, making the PUF resistant against voltage variations. Additionally, the PUF cell is designed to be reconfigurable with no area overhead, which enables stabilization without redundancy on chip. Thanks to the highly stable and self-regulated PUF cell and the zero-overhead stabilization scheme, a 0.00182% native BER is obtained after reconfiguration. The proposed design shows 0.12%/10 {\deg}C and 0.057%/0.1-V bit error across the military-grade temperature range from -55 {\deg}C to 125 {\deg}C and supply voltage variation from 0.7 to 1.4 V. The total energy per bit is 15.3 fJ. Furthermore, the unstable bits can be detected by sweeping the body bias instead of temperature during enrollment, thereby significantly reducing the testing costs. Last but not least, the prototype exhibits almost ideal uniqueness and randomness, with a mean inter-die Hamming distance (HD) of 0.4998 and a 1020x inter-/intra-die HD separation. It also passes both NIST 800-22 and 800-90B randomness tests.