Highly Stable Reconfigurable TERO PUF Architecture for Hardware Security Applications

This work introduces a novel 128-bit transient effect ring oscillator (TERO)-based physically unclonable function (PUF) designed for Intel MAX 10 field-programmable gate arrays (FPGAs). A reliable PUF solution suitable for security applications targeting high stability and area efficiency is presented. The proposed cell consists of two cross-coupled reconfigurable ring oscillators (ROs) aiming to achieve zero-observed instability at both golden key (GK) and under temperature variations. Conversely to the conventional application-specific integrated circuits (ASIC) approaches, which use the mean cycles to collapse (CTC), here the calibration process was performed by considering the CTC standard deviation extracted at GK conditions, namely, 1.2 V and $25~^{\circ }$ C. The experimental results demonstrate that after the calibration process and considering a 1.64% of masked bits, the proposed solution shows a bit error rate (BER) lower than $\mathbf {1.56\times 10^{-4}\%}$ , the minimum observable quantity for the adopted statistical set across the entire analyzed temperature range. Further, the solution also shows an excellent uniqueness of 49.78%, close to the ideal value of 50%. This is achieved at the cost of two logic array blocks (LABs) per bit.