Low-autocorrelation random number generator based on adiabatic quantum-flux-parametron logic

We propose a true random number generator (TRNG) based on adiabatic quantum-flux-parametron (AQFP) logic. This AQFP TRNG corresponds to an AQFP buffer chain with the input current removed, which enables the generation of random bits via thermal fluctuation. To realize ultralow autocorrelation, several isolation inductors are inserted between adjacent buffers in the AQFP TRNG, thereby reducing the impact of the back action between buffers. We design and fabricate an AQFP TRNG using the AIST 10 kA/cm2 Nb high-speed standard process and evaluate the quality of the generated random bit streams. For a 217-bit random stream obtained from the AQFP TRNG at 100 kHz, the autocorrelation function is 5.00 × 10−3. Furthermore, we evaluate a 220-bit random stream from the AQFP TRNG using a statistical test suite provided by the National Institute of Standards and Technology. The bit stream passed 14 out of 15 tests, which suggests that the proposed AQFP TRNG can be used for applications such as stochastic computing and stochastic local search algorithms.