A lightweight true random number generator based on multi‐stage sampling the current starve based ring oscillator

Abstract

In this letter, a novel true random number generator (TRNG) with high energy‐efficient and throughput is proposed for cryptographic systems. The current starve based ring oscillator (CSRO) is biased in the subthrehold region as an entropy source. An individual ring oscillator (RO) is sampled using multiple sampling points of the CSRO working in the sub‐threshold region to obtain a multi‐channel sequence output, thereby fully exploiting the randomness of the entropy source. The proposed TRNG is implemented using a standard 40nm CMOS technology and the simulation results show that it provides high‐quality and 20.66 Mbps random sequences while only consuming 11.46 μW at 1.1 V, 25°C. In addition, the proposed TRNG passes the NIST SP 800‐22 and the NIST SP 800‐90B tests without post‐processing and outperforms the state‐of‐the‐art in terms of energy consumption per bit of the output bitstream, reaching 0.555pJ/bit.