A Robust Digital Random Number Generator Based on Transient Effect of Ring Oscillator

This paper presents the FPGA (Field Programmable Gate Array) implementation and coupling analysis of a metastability-based random number generator (RNG). The metastability is obtained by using transient effect ring oscillators (TEROs) and the RNG uses regular sampling of irregular waveform method. As the proposed RNG is designed with digital logic gates only, it is implemented on a Xilinx ZedBoard Zynq-7000 evaluation platform. The output bitstream satisfies NIST 800-22 statistical tests of randomness without any need for postprocessing at a high bit rate. The proposed RNG uses less number of components compared to previously reported TERO based RNGs, thus suggesting lower power consumption and area. Additionally, correlation-based cryptanalysis study is conducted on the proposed RNG. In classical ring oscillator (RO) based RNGs, the ring oscillators need to be located at a distance from each other to avoid coupling between adjacent ROs. This study demonstrates that unlike classical RO based RNGs, the proposed RNG is able to guarantee high stability. It is insensitive to the locking phenomenon, hence leading to more compact RNG design.