$\mu $ RNG: A 300–950 mV, 323 Gbps/W All-Digital Full-Entropy True Random Number Generator in 14 nm FinFET CMOS
Sanu K. Mathew, David Johnston, Sudhir K. Satpathy, Vikram Suresh, Paul Newman, Mark A Anders, Himanshu Kaul, Amit Agarwal, Steven Hsu, Gregory Chen, Ram Kumar Krishnamurthy · IEEE Journal of Solid-State Circuits · 2016
This paper describes μRNG, an ultra-lightweight all-digital full-entropy true-random number generator (TRNG), fabricated in 14 nm high-k/metal-gate FinFET CMOS, targeted for on-die generation of cryptographic keys in energy-constrained IoT and wearable platforms. The μRNG combines the entropy of multiple independent sources to generate an output bitstream that is indistinguishable from an ideal unbiased entropy source. Three independent self-calibrating all-digital entropy sources, coupled with XOR feedback shift-register based correlation suppressors and an in-line compact Barak-Impagliazzo- Wigderson (BIW) extractor enable ultra-low energy consumption of 3 pJ/full-entropy bit with a dense layout occupying 1008 μm2, while achieving: (i) 162.5 Mbps full-entropy throughput at 1.3 GHz operation, with total power consumption of 1.5 mW and leakage power component of 90 μW, measured at 0.75 V, 25°C, (ii) mutually uncorrelated raw bitstreams from the three entropy sources with phi-coefficient cross-correlation∞> 0.99, (iv) hysteresis-free extracted output for lags 1-1000, with ACF ~0 within 95% confidence bounds of a Gaussian distribution (μ = 0, σ2= 0.002), (v) wide operating supply voltage range of 300-950 mV with throughput scaling to 225 Mbps at 950 mV and robust subthreshold voltage performance of 400 Kbps, 4 μW, measured at 300 mV, 25°C, (vi) peak energy-efficiency of 323 Gbps/W at near-threshold voltage of 400 mV, with full-entropy throughput of 8.6 Mbps, total power consumption of 27 μW, (vii) 6.5× reduction in gate count and 5.4× lower energy consumption compared to conventional AES-based entropy extractors.