A Sub-pico Joules Per Bit Robust Physical Unclonable Function Based on Subthreshold Voltage References
Yuan Cao, Chip-Hong Chang, Wenhan Zheng, Xiaojin Zhao · 2018
Low power, lightweight and robust physical unclonable function (PUF) is a sought-after for IoT device identification/authentication. This paper presents a low power PUF design with high reliability against temperature and supply voltage variations. A response bit is extracted by comparing a pair of identically designed subthreshold voltage references. The voltage difference due to device mismatch is digitized and registered in a bidirectional counter, which can be used to identify and filter out the unstable response bits. The readout circuit works in tandem with the proposed double sampling technique to reduce the bias of components that are not the main entropy source of response bits. The proposed design is evaluated by extensive simulation using standard 65 nm CMOS process. It consumes merely 0.16 pJ/bit. The simulated uniqueness is an almost ideal 50.03%. Due to the intrinsic stability of voltage references, the reliability of its native response is 98.17% for the supply voltage variation from 1 V to 1.4 V and 97.60% for the temperature variation from 0 ° C to 80 °C. The generated response bitstream has passed both the autocorrelation test and NIST randomness test.