When Variability Meets Security

Our digital economy demands increasingly functional, reliable, and secure integrated circuits (ICs). Central to this pursuit is the challenge of variability-the prime adversary of IC reliability. Left unchecked, variability imperils the safety and dependability of modern electronics. Notably, time-dependent variability (TDV), manifesting through phenomena like Random Telegraph Noise and aging, exacerbates these vulnerabilities. Despite significant strides, accurately forecasting and mitigating TDV's effects remains elusive. Yet variability, paradoxically, is also a source of innovation. In resource-constrained devices such as wearables, Physical Unclonable Functions (PUFs) or True Random Number Generators (TRNGs) exploit manufacturing-induced variability to enable lightweight cryptographic security. Furthermore, TDV itself, while threatening reliability and security, can be repurposed to craft aging-resilient PUFs and TRNGs as well as solutions against chip counterfeiting. This paper reframes TDV from a challenge to an asset, exploring its exploitation to strengthen cybersecurity.