High-efficiency TRNG Design Based on Multi-bit Dual-ring Oscillator

Unpredictable true random numbers are required in security technology fields such as information encryption, key generation, mask generation for anti-side-channel analysis, algorithm initialization, and so on. At present, the true random number generator (TRNG) is not enough to provide fast random bits by low-speed bits generation. Therefore, it is necessary to design a faster TRNG. This work presents an ultra-compact TRNG with high throughput based on a novel extendable dual-ring oscillator (DRO). Owing to multiple bits output per cycle in DRO can be used to obtain the original random sequence, the proposed DRO achieves a maximum resource utilization to build a more efficient TRNG, compared with the conventional TRNG system based on ring oscillator (RO), which only has a single output and needs to build multiple groups of ring oscillators. TRNG based on the 2-bit DRO and its 8-bit derivative structure has been verified on Xilinx Artix-7 and Kintex-7 FPGA under the automatic layout and routing and has achieved a throughput of 550 Mbps and 1,100 Mbps, respectively. Moreover, in terms of throughput performance over operating frequency, hardware consumption, and entropy, the proposed scheme has obvious advantages. Finally, the generated sequences show good randomness in the test of NIST SP800-22 and Dieharder test suite and pass the entropy estimation test kit NIST SP800-90B and AIS-31.