A Novel Configurable Ring Oscillator PUF Design with Improved Quality and Security

Abstract

Physically Unclonable Functions (PUFs) have emerged as a promising security primitive for lightweight authentication. As one of its silicon-based implementations, configurable Ring Oscillator (RO) PUF has attracted extensive attention for its simplicity. However, system variation and environmental variations can deteriorate the uniformity and reliability of its challenge-response pairs (CRPs). In this paper, a novel response mapping function using two-step subtraction rather than traditional one-step subtraction is proposed for configurable RO PUF. Besides, to resist modeling attacks, a segment-reversal obfuscation scheme leveraging frequency difference is proposed, which introduces no additional interactions or helper data. Hardware implementation demonstrates that the proposed schemes incur negligible area and power overheads. Characterization across 50 field-programmable gate arrays (FPGAs) validates that the proposed design achieves excellent uniqueness and delivers significant improvements in both uniformity and reliability over a wide temperature and voltage range. Security evaluations using feedforward neural network (FNN) and evolution strategy (ES) over millions of CRPs confirm that the proposed obfuscation scheme is secure enough to defeat against modeling attack.