A true random number generator with high bit rate and low energy efficiency

Abstract

Summary In this paper, a novel feedback architecture of true random number generator based on tetrahedral ring oscillator is proposed. The random raw bits are fed back to produce control voltages, which control the transmission gates in ring oscillators. Since random fluctuations of the control voltages increase the phase jitter of the oscillator, this architecture improves the bit rate and randomness of random sequence. Besides, a post‐processor is designed to enhance the randomness further. The circuit is implemented in TSMC 40‐nm complementary metal oxide semiconductor (CMOS) process, and it takes up an area of 85 × 51 μm. Measurement results show that the random number sequences pass the statistical randomness tests, with a low power consumption of 67 μW, high speed of 45 Mbps, and low energy efficiency of 1.48 pJ/bit.