RRAM Random Number Generator Based on Train of Pulses

Binbin Yang,Álvaro Gómez-Pau,Francesca Campabadal,Daniel Arumí,Rosa Rodríguez-Montañés,Liang Fang,Salvador Manich,Mireia Bargalló González

doi:10.3390/electronics10151831

Abstract

In this paper, the modulation of the conductance levels of resistive random access memory (RRAM) devices is used for the generation of random numbers by applying a train of RESET pulses. The influence of the pulse amplitude and width on the device resistance is also analyzed. For each pulse characteristic, the number of pulses required to drive the device to a particular resistance threshold is variable, and it is exploited to extract random numbers. Based on this behavior, a random number generator (RNG) circuit is proposed. To assess the performance of the circuit, the National Institute of Standards and Technology (NIST) randomness tests are applied to evaluate the randomness of the bitstreams obtained. The experimental results show that four random bits are simultaneously obtained, passing all the applied tests without the need for post-processing. The presented method provides a new strategy to generate random numbers based on RRAMs for hardware security applications.

Highlights

Random number generators (RNGs) are fundamental components in applications, such as problem-solving techniques, industrial simulations, computer games or hardware encryption modules in communication systems [1]
Experimental results show that multiple random bits can be extracted from the number of RESET pulses needed to be applied to the resistive random access memory (RRAM) to induce a specific resistance state
The proposed true random number generators (TRNGs) extracts random bits from the number of RESET pulses required to drive an RRAM to a specific threshold resistance

Summary

Introduction

Random number generators (RNGs) are fundamental components in applications, such as problem-solving techniques, industrial simulations, computer games or hardware encryption modules in communication systems [1]. Recent works have been focused on the extraction of random numbers by exploiting the cycle-to-cycle variability of RRAMs [14,15], the device-to-device variability [16], the competition between paired devices [17,18], the combination of cycle-to-cycle and device-to-device variability [19] and the occurrence of RTN [20,21,22] All these existing RRAM-based TRNGs still suffer from some limitations, such as complexity in design, need for post-processing or high cost. In this context, the present work investigates the behavior of RRAMs under the application of a train of RESET pulses for the generation of random bits.

Experimental Set-Up

Resistance Variability under Pulse Programming

Random Number Generator Proposal

Conclusions