Easy-to-build Arbiter Physical Unclonable Function with enhanced challenge/response set

Abstract

Physical Unclonable Functions (PUF) are novel chip identifiers with an extensive array of uses in security applications. In this paper, we propose a novel PUF that has a very large Challenge/Response (C/R) space in a given area, while being resistant to modeling attacks at the same time. We name this design S-ArbRO PUF. We study the variability of the proposed PUF and its reliability to temperature variations. In addition, we perform a modeling attack on the PUF to get an insight into its resistance to modeling. For an S-ArbRO PUF with 24 ring oscillators (ROs), we observe a variability of 46%, which is equivalent to the variability of a traditional RO PUF built out of the same ring oscillators. The proposed design is highly stable to temperature variations with a maximum of 4% bit flips at 65C. For an RO count of 24, the total number of C/R pairs in the design is over 63K, compared to 276 for a traditional RO PUF with the same number of ROs. S-ArbRO PUF is more secure as a logistic regression (LR)-based modeling attack requires a training set of over 47K C/R pairs to model with a 96% correct prediction, while an equivalent sized Arbiter PUF breaks at only 240 C/R pairs.