Abstract
Lightweight physical unclonable functions (LPUFs) exploit manufacturing process variations of semiconductor integrated circuits (ICs) to protect IoT-based electronic and smart devices from new cyberattacks. This paper proposes two novel security techniques to enhance the robustness of LPUFs using configurable-based ring oscillator PUFs (CF-ROPUFs). These techniques are the intra-die frequency aware (IFA) approach to improve PUF reliability and the logarithmic gamma function ( Ln_{\gamma } ) technique to enhance PUF randomness. The lightweight CF-ROPUF design is realized on hardware, and data samples are collected under varying temperatures and supply voltages over a population of 30 Spartan-3E FPGAs. Experimental results of the IFA technique in terms of average Hamming Weight (HM) demonstrate that the percentage of the reliable RO sample frequencies PUF output is 98.5%. For the analysis, PUF reliability is evaluated in terms of accuracy, repeatability, and reproducibility, the international organization for Standardization (ISO) standards. The results indicate that the RO samples are accurately measured from the CF-ROPUFs mapped in all the chips. After using the proposed 1-out-of-r coding algorithm, the results demonstrate high average repeatability of 98.2% and a magnified average reproducibility of 99.63%. It is also shown that our CF-ROPUF design is immune from accelerated aging impacts reliability issues. Statistical results show that Ln( Ln_{\gamma } ) enhances the normality and mitigate the negative impacts of the systematic process variations on RO sample frequencies. Randomness results show that CF-ROPUF binary response bits can successfully pass the 15 NIST test suites for true randomness with an enhanced percentage, 93.3%, with the application of the 1-out-of-r coding.