Stable and secure delay-based physical unclonable functions using device aging

The modern secure systems are designed to require ultra-low power secure solutions due to their energy constraints. Compared to the classical cryptography approaches, the physical unclonable functions (PUFs) have emerged as a novel security primitive with the property of low power/energy, small area, and high speed. Among the family of PUFs, delay-based PUF takes advantage of the process variation on the gate delays. However, it suffers the problem of instability against operational variations. In this paper, we have proposed to use device-aging to improve the stability of the delay-based PUF which induces negligible energy and area cost. We test to compare the stability of PUFs before and after device-aging against temperature and supply voltage variations.