基于环形振荡器的物理不可克隆函数的设计与验证

Design and Verification of RO-based PUF on FPGA

为了验证物理不可克隆函数(Physical Unclonable Function,PUF)的有效性,试验必须针对大量芯片的微延迟特性进行建模。尽管仿真的方式能够提供近似的结果,但通过片上试验能获得更加精确的结果。借助FPGA工具制造硬宏,在多块同型号FPGA上分析了基于环形振荡器(Ring Oscillator,RO)的物理不可克隆函数。其核心步骤是通过对相邻RO的振荡频率计数后相互比较,得到1024比特长度的响应输出。在多次试验测试后,得到了片内和片间汉明距,并作为PUF性能的指标参数——唯一性、可靠性。结果表明,常温下的平均唯一性为48.01%,平均可靠性为1.75%。

To validate the effectiveness of a Physical Uncloneable Function (PUF), it needs to be characterized by delay model over a large population of chips. Though simulation methods can show approximate results, an on-chip experiment produces more accurate results. This paper includes the test of the Ring Oscillator based PUFs on several same-model FPGAs with the hard-macro made by FPGA tool. The core process of the design is counting the oscillating frequencies in pairs and comparing the counters' values to form a 1024-bit response. We obtain the intra-die and inter-die Hamming distance by the experiments and treat them as the quality factors of a PUF such as uniqueness and reliability. The results show an average uniqueness of 48.01%, and an average reliability of 1.75%.