BTI resilient TG-based high-performance ring oscillator for PUF design

Abstract

Hardware-based security primitives are essential in protecting and securing a system in the Internet of Things (loT) applications. The Physically Unclonable Functions (PUFs) have come out to be the most popular low-cost security primitives for authentication and cryptographic key generation. However, the PUF’s stability with aging over time still limits its usefulness and widespread acceptance. For instance, RO-based PUF faces bit flip issues because of the aging degradation of threshold voltages of transistors used in making RO. This phenomenon depreciates the reliability of RO-PUF for hardware security applications. Some of the last pieces of literature focused on improving PUF robustness against aging. However, the power budget of the ring oscillator used in designing these PUFs limits their usage for low-power applications. Keeping the power constraint in mind, a low-power variant of RO-PUF is much needed. In this paper, we propose a new energy-efficient and aging resilient inverter and RO based on an aging resilient inverter design. The proposed inverter is 22.57% less power-consuming and 16% faster than the conventional Aging Resilient inverter while showing nearly identical aging characteristics without significant increment in area overhead. Also, the Ring Oscillator designed from the proposed inverter shows nearly 1.5% higher frequency than the conventional Aging resilient Ring Oscillator for the same number of inverter stages while maintaining around 46% lesser standard deviation from mean oscillation frequency against various PVT conditions. For the proposed Ring Oscillator, the absolute value of frequency gradient with the temperature is around 4.9% lesser than the conventional Aging resilient Ring Oscillator, making the design a good fit not only for low power budget applications but also for better reliability over temperature. © 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.