面向物理不可克隆函数的可靠性与随机性增强技术

传统的基于环形振荡器物理不可克隆函数(RO-PUF)因温度、电压、器件老化等影响,存在着物理不可克隆函数(PUF)输出不稳定的可靠性问题以及振荡器频率不随机分布的安全性问题.针对PUF可靠性问题,提出一种类斜率频率补偿方案.该方案通过测量出温度与振荡器频率的线性关系,再选择与不稳定输入输出响应对(CRP)中相同线性关系的其他振荡器相互补偿,使得不稳定CRP输出可靠响应.针对PUF的安全性问题,提出一种基于平均值绝对差的方案.该方案首先测量出每块芯片上振荡器的平均频率,其次再多次过滤相应振荡器的平均值得到随机的剩余频率,最终PUF的输出响应能够服从随机分布.分析与实验结果表明,该方案能有效提高RO-PUF安全性与可靠性.

Reliability and randomness enhancing techniques for physical unclonable functions

Due to the impact of temperature, voltage and device aging, the traditional Ring Oscillator based Physical Unclonable Functions (RO-PUF) suffer from two main issues, unreliability of Physical Unclonable Functions (PUF) response and nonrandom distribution of Ring Oscillator (RO) frequencies. In order to improve the PUF reliability, an approximate frequency slope compensation method that uses the slope relationship between RO frequency and temperature to compensate the instable RO frequency was proposed in this paper. As a result, the instable Challenge-Response Pairs (CRP) perform the reliable responses. To enhance the security, a new scheme based on Mean Absolute Difference (MAD) was proposed in this paper. Firstly, the scheme measured the RO's average frequency of each chip, then filtered the corresponding RO's average frequency multiple times to extract the true random frequency. Consequently, the output of PUF follows the random distribution. The experimental results show that the proposed scheme can improve RO-PUF's reliability and security effectively.