A 3 μW CMOS true random number generator with adaptive floating-gate offset cancellation

This paper presents two novel hardware random number generators (RNGs) based on latch metastability. We designed the first, the DC-nulling RNG, for extremely low power operation. The second, the FIR-based RNG, uses a predictive whitening filter to remove nonrandom components from the generated bit sequence. In both designs, the use of floating-gate memory cells allows us to predict and compensate for DC offsets and other nonrandom influences while minimizing power consumption. We also present an efficient digital post-processing technique for improving randomness. We fabricated both RNGs in a standard 0.35 mu m CMOS process. The DC-nulling RNG occupied .031 mm(2) of die area, while the FIR-based RNG occupied 1.49 mm(2).