A Ring Oscillator PUF Architecture With Enhanced Challenge-Response Set

Abstract

Physically Unclonable Functions (PUFs) are new hardware solution for low cost and secure communication primitives such as hardware authentication and secure key generation. PUFs use the random properties of a device to produce unique data. Ring Oscillator PUFs (RO PUF) are one of the most applicable PUFs because of its good reliability and easy implementation on FPGAs. One major problem of Ro PUFs is limited Challenge-Response pairs number. We consider this problem and introduce a new architecture of RO PUF that increases Challenge-Response pairs of a typical PUF with using minimum resources. In our architecture, we use an XOR gate to prevent direct response disclosure and increase our response unpredictability. In this manner, we increase Challenge-Response pairs up to $\frac{{n\left( {n - 1} \right)}}{2}$. We also show the result of the unity and uniqueness of our proposed PUF by implementing 110 PUFs on five XC3S400 FPGAs.