Design of a Highly Randomized Crossover Ring Oscillator Physical Unclonable Function

Silicon Physical Unclonable Function (PUF) is the most critical hardware security circuit that exploits unique identification or random key generation utilizing manufacturing process variations. Numerous PUFs are in the literature amongst Ring Oscillator (RO) PUFs are mainly used for their simple structures. However, the uniqueness of RO-PUF is less efficient than its counterpart, arbiter PUFs. This paper proposes highly unique or random outputs of RO-PUF using a crossover technique among different inverters in the RO chains. The Challenge Response Pairs (CRPs) of the proposed design deliver heightened randomness that may apply to cryptography key generation. The design is implemented in the Proteus tool and tested in the NIST randomness test suit. A significant small statistical p-value for the proposed approach results in a robust randomized output. The results show that the randomness of the output frequency is extreme compared to other PUFs.