Unveiling the True Power of the Latched Ring Oscillator for a Unified PUF and TRNG Architecture
Riccardo Della Sala, Davide Bellizia, Giuseppe Scotti
Abstract
This work presents a novel proposal for utilizing the latched ring oscillator (LRO) as a reconfigurable entropy source, outperforming the existing literature on both physical unclonable functions (PUFs) and true random number generators (TRNGs). The PUF working principle and mathematical model are proposed in this manuscript for the first time as well as its performance measured on FPGA. The proposed LRO-based PUF is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times $ </tex-math></inline-formula> more compact than state-of-the-art PUFs on FPGA. The LRO TRNG architecture has been revisited, and an XOR-tree-based postprocessing technique has been introduced to increase the throughput from 0.76 up to 800 Mbit/s, paving the way for a novel class of high-throughput reconfigurable entropy sources. The results of NIST tests carried out also under supply voltage and temperature variations have demonstrated robust key extraction and secure random number generation for different applications. This comprehensive proposal aims to advance the state of the art in compact and high-throughput entropy sources, catering to the increasing demands of modern cryptographic hardware.