Reliable and Anti-cloning PUFs Based on Configurable Ring Oscillators

Ring oscillator Physical Unclonable Function (RO PUF) is a popular silicon PUF due to its ease of implementation on both ASIC and FPGA. However, RO PUFs have severe reliability issues when the operating environment deviates from the nominal condition and security issues as cloning attacks have been reported. In this work, we propose to build configurable RO PUFs based on the notions of configurable RO PUF [6, 16] and highly flexible RO PUF [22] to address these concerns. First, we demonstrate how to build RO PUF from single flexible ROs, which improves both the reliability and hardware efficiency of RO PUFs. Then we propose a novel dual voltage based configurable RO PUF to mitigate the cloning attacks. Our experimental results show that our configurable RO PUFs are more reliable and hardware efficient than the existing RO PUF designs. Using the flexible RO PUF [22] as baseline, we have reduced the bit flip rate by 69% and improve the hardware utilization by 136%. In addition, the anti-cloning approach generates PUF data significantly different from the original PUF secret (average 47.5% Hamming distance) which makes potential cloning attacks very difficult.