A Chaotic Ring Oscillator based Random Number Generator

True Random Number Generator (TRNG) circuits play an important role in hardware security. Traditional Ring Oscillator (RO) based TRNGs aim to amplify thermal noise and supply noise jitters. To increase randomness, traditional RO based TRNGs harvest random noise from large number of stages resulting in large area and power. We propose a Chaotic Ring oscillator based random number Generator (CRNG) for CMOS implementation. This circuit uses nonlinear elements which are straightforward to implement in CMOS to bring about chaotic behavior. We demonstrate that the proposed CRNG passes tests for randomness and are immune to modeling attacks. Albeit small in magnitude, the proposed CRNG also harvests physical noise which acts as a compounder over chaos. The proposed CRNG circuit is small in area, scales well with technology, operates at low voltages and does not require any special manufacturing process. The output bit stream of the proposed CRNG implemented in a 45nm process was tested using the NIST test suite and it passes 11 tests. Results show that the proposed CRNG occupies an area of 93.1 mu m(2) and has a throughput of 127 Mbps at a power of 1.1 mW. This compares very well against state of the art TRNGs.