Side channel modeling attacks on 65nm arbiter PUFs exploiting CMOS device noise

Abstract

Abstract-Physically Unclonable Functions (PUFs) are emerging as hardware security primitives. For so-called strong PUFs, the number of challenge-response pairs (CRPs) increases exponentially with the required chip area in the ideal case. They can provide a mechanism to authenticate chips which is inherently unique for every manufactured sample. Modeling of the CRP behavior through Machine Learning (ML) has shown to be a threat however. In this paper, we exploit repeatability imperfections of PUF responses as a side channel for model building. We demonstrate that 65nm CMOS arbiter PUFs can be modeled successfully, without utilizing any ML algorithm. Data originates from real-world measurements and hence not from simulations. Modeling accuracies exceeding 97% are obtained, which is comparable with previously published ML results. Information leakage through the exploited side channel should be considered for all strong PUF designs. Combined attack strategies, whereby repeatability measurements facilitate ML, might be effective and are recommended for further research.

Why Attackers Lose: Design and Security Analysis of Arbitrarily Large XOR Arbiter PUFs

“…This fact theoretically supports the common assumption [6,14] about Gaussian delay values in Arbiter PUF research.…”

“…Note that this model does not make any assumptions about distribution or model of ∆D Model (c). Delvaux and Verbauwhede [6] were the first to propose this model.…”

“…The idea of stability is also captured by the notions of reliability [4], repeatability [6], or robustness [2] in other literature, although those notions might not formally be equivalent.…”

“…However, as shown by Rührmair et al [32] in a comprehensive overview of feasible attacks on various types of PUFs, XOR PUFs can be attacked if k is small. As all known Arbiter PUF implementations suffer from a portion of challenges that do not provide stable responses [6], large XOR Arbiter PUFs are infeasible to build, as their stability will decrease exponentially with growing k as an induction argument shows.…”

“…Centerpiece of our analysis is a combination of a linear function that models noise-free arbiter chain delays and a stochastic process that models measurement and evaluation noise. This model was introduced by Majzoobi [24] and was later used by Delvaux and Verbauwhede [6] as the foundation for a noise-based side-channel attack.…”