Reliability evaluation of IC Ring Oscillator PUFs.

Silicon-based Physical Unclonable Functions (PUFs) have become a popular solution to provide security in many applications. PUFs are circuits that take advantage of the innate variability of the fabrication processes to deliver a different output for each implementation of the same circuit. This unique response needs to be reliable to environmental conditions, like temperature variations or power supply variations, but also needs to stay stable over time, i.e., the circuit output should be resilient to aging. In this paper, a reliability study of a PUF based on Ring Oscillators (RO) in a 65-nm CMOS technology is presented. Experimental results are performed on different die samples, including temperature and power supply variations. Aging degradation is characterized using accelerated aging tests, taking advantage of the unique properties of two arrays of ROs included in a chip specifically designed to accurately characterize aging degradation.