基于晶闸管型延迟单元的芯片指纹PUF电路

Thyristor-Based Physical Unclonable Function Circuit for Chip Fingerprint

提出一种面向芯片指纹应用的物理不可克隆函数(PUF)电路,包括基于晶闸管型延迟单元的工艺敏感电路、时间偏差放大器和时间偏差比较器三个部分。工艺敏感电路由两个相同的晶闸管型延迟单元组成。晶闸管型延迟单元对工艺变化非常敏感,而在电源电压与温度变化时稳定性较强,可有效改善PUF电路的唯一性与稳定性。时间偏差放大器对工艺敏感电路输出的微弱延时差进行放大,减小延时差对噪声和时间偏差比较器精度的敏感性,使比较器能够产生稳定的输出,进一步提高PUF电路的稳定性。基于0.18μm CMOS工艺,对电路进行设计与仿真。结果表明,PUF电路的输出具有良好的海明距离统计分布特征,当温度在-40℃~100℃范围、电源电压在1.7~1.9V范围变化时,PUF电路的稳定性可达95.8%。

A reliable physical unclonable function (PUF)circuit for chip fingerprint was proposed.It was composed of thyristor-based sensors,time difference amplifiers and time difference comparators.The thyristorbased sensor was built by using two identical thyristor delay elements,which were very sensitive to process variation and showed little sensitivity to supply voltage and temperature variations,so as to improve effectively the uniqueness and stability of PUFs.A time difference amplifier was used to amplify the slight delay time difference from selected thyristor-based sensors.The amplification reduced the susceptibility of delay time difference to the noise and offset in time difference comparator,which ensured that the comparator could produce a stable output. And the stability of PUFs was further improved with the introduction of time difference amplifier.The thyristorbased PUF was designed in a 0.18μm CMOS process.Simulated results showed that the thyristor-based PUF had a good hamming distance statistical distribution and a high stability of 95.8%at a temperature variation from -40℃ to 100℃and a supply voltage variation from 1.7Vto 1.9V.