A Novel Ultra-Compact FPGA-Compatible TRNG Architecture Exploiting Latched Ring Oscillators

In this brief we present a novel, ultra-compact, True Random Number Generator (TRNG) architecture and its FPGA implementation. The proposed Latched Ring Oscillator (LRO) TRNG allows the generation of a TRNG bit from a single FPGA Slice. Despite its very compact structure, the proposed LRO-TRNG relies on both meta-stability and accumulated jitter as entropy sources, and exhibits very good results in terms of unpredictability and randomness. The proposed architecture has been implemented on Xilinx Spartan-6 devices and the TRNG performances have been extensively validated under supply voltage and temperature variations. Measurements results have shown that the LRO-TRNG exhibits an estimated entropy of about 7.99834 per bit (according to T8 test of the AIS-31) and a throughput of 0.76 Mbits/s with a 50MHz clock. A comparison against the state of the art shows that the proposed LRO-TRNG outperforms most of the previously published TRNGs, in terms of the ratio between throughput and FPGA resources usage.