Infinite Noise TRNG (True Random Number Generator)

The Infinite Noise TRNG is a USB key hardware true random number generator. It uses what I call a “Modular Entropy Multiplier” architecture (previously Infinite Noise Multiplier or FireBug). Besides being simple, low-cost, and fast, it is much easier to get right than other TRNGs. It naturally defends against influence from outside signals, such as radio interference and power supply noise, making it simple to build securely, without requiring an expert in analog design. Modular entropy multipliers produce a provable and easily measured level of entropy based on thermal noise, approximately equal to log2(K) per output bit, where K is a gain between 1 and 2 set by two resistors around an op-amp. A “health monitor” can track this and verify that the output entropy is within the expected range, which for the Infinite Noise TRNG described below is within 2% of log2(1.82). Modular entropy multipliers are suitable for both board level implementation and ASIC implementation. Speed is limited by the speed of a gain stage and a comparator, and can run in excess of 100 Mbit/second per second with high performance components. Cheap solutions with CMOS quad op-amps can run at 8Mbit/second.”