A novel true random number generator based on a stochastic diffusive memristor

Hao Jiang,Zhongrui Wang,Rivu Midya,Qiangfei Xia,Daniel Belkin,J Joshua Yang,Qing Wu,Saumil Joshi,Mingyi Rao,Mark Barnell,Siyan Lin,Can Li,Yunning Li,Sergey E Savel’Ev

doi:10.1038/s41467-017-00869-x

Abstract

The intrinsic variability of switching behavior in memristors has been a major obstacle to their adoption as the next generation of universal memory. On the other hand, this natural stochasticity can be valuable for hardware security applications. Here we propose and demonstrate a novel true random number generator utilizing the stochastic delay time of threshold switching in a Ag:SiO2 diffusive memristor, which exhibits evident advantages in scalability, circuit complexity, and power consumption. The random bits generated by the diffusive memristor true random number generator pass all 15 NIST randomness tests without any post-processing, a first for memristive-switching true random number generators. Based on nanoparticle dynamic simulation and analytical estimates, we attribute the stochasticity in delay time to the probabilistic process by which Ag particles detach from a Ag reservoir. This work paves the way for memristors in hardware security applications for the era of the Internet of Things.

Highlights

The intrinsic variability of switching behavior in memristors has been a major obstacle to their adoption as the generation of universal memory
A true random number generator (TRNG) is a hardware component that generates a string of random bits, which can be used as a cryptographic key
The Ag doping ratio in the Ag:SiO2 switching layer was determined to be around 17% by X-ray photoelectron spectroscopy (XPS; Supplementary Fig. 1a)

Summary

Introduction

The intrinsic variability of switching behavior in memristors has been a major obstacle to their adoption as the generation of universal memory. We propose and demonstrate a novel true random number generator utilizing the stochastic delay time of threshold switching in a Ag:SiO2 diffusive memristor, which exhibits evident advantages in scalability, circuit complexity, and power consumption. The intrinsic variation in switching parameters is a major challenge for some applications such as non-volatile memory[25] This random behavior can be helpful in stochastic computing and hardware security applications[26,27,28]. Besides the need for complicated probability tracking and careful tuning of the applied voltage/current, a pair of SET and RESET pulses were required to generate each random bit since those memristive devices are non-volatile. None of the aforementioned memristor based TRNGs passed all the 15 NIST Special Publication 800-22 randomness tests[32] even with post-processing of data, leaving the claimed true nature of the randomness debatable. The new mechanism based on ionic/atomic motion indicates that our TRNG may be less vulnerable to environmental variations such as radiation relative to other electron-based TRNGs36

Methods

Results

Conclusion