TCO-PUF: A Subthreshold Physical Unclonable Function

A Physical Unclonable Function (PUF) is a promising technology towards comprehensive security protection for integrated circuit applications. It provides a secure method of hardware identification and authentication by exploiting inherent manufacturing process variations to generate a unique response for each device. Subthreshold Current Array PUFs, which are based on the non-linearity of currents and voltages in MOSFETs in the subthreshold region, provide higher security against machine learning-based attacks compared with delay-based PUFs. However, their implementation is not practical due to the low output voltages generated from transistor arrays. In this paper, a novel architecture for a PUF, called the "Two Chooses One" PUF or TCO-PUF, is proposed to improve the output voltage ranges. The proposed PUF shows excellent quality metrics. The average inter-chip Hamming distance is 50.23%. The reliability over the temperature and +/- 10% supply voltage fluctuations is 91.58%. In terms of security, on average TCO-PUF shows higher security compared to delay-based PUFs and existing designs of Subthreshold Current Array PUFs against machine learning attacks.