Quantifying Jitter Transfer for Differential Measurement: Enhancing Security of Oscillator-Based TRNGs

TL;DR

This paper presents a method to accurately measure individual oscillator jitter in multi-ring oscillator TRNGs by revisiting the jitter transfer principle, improving entropy estimation and security assurance.

Contribution

It introduces a novel approach combining jitter transfer principles with oscillator design to enable differential measurements of individual jitter parameters.

Findings

Simulations confirm improved jitter measurement accuracy.

Hardware experiments validate the method's effectiveness.

Enhanced entropy rate estimation for security compliance.

Abstract

The aim of this paper is to describe a way to improve the reliability of the measurement of the statistical parameters of the phase noise in a multi-ring oscillator-based TRNG. This is necessary to guarantee that the entropy rate is within the bounds prescribed by standards or security specifications. According to the literature, to filter out global noises which may strongly affect the measurement of the phase noise parameters, it is necessary to perform a differential measure. But a differential measurement only returns the parameters of the phase noise resulting of the composition of the noises of two oscillators whereas jitters parameters of individual oscillators are required to compute the entropy rate of a multi-ring oscillator-based TRNG. In this paper, we revisit the "jitter transfer principle" in conjunction with a tweaked design of an oscillator based TRNG to enjoy the precision of differential measures and, at the same time, obtain jitter parameters of individual oscillators. We show the relevance of our method with simulations and experiments with hardware implementations.