A Bias and Correlation Free True Random Number Generator Based on Quantized Oscillator Phase under Sub-Harmonic Injection Locking

Abstract

In this work, we demonstrated a novel oscillator phase based true random number generator (TRNG) design that can be high speed, and bias and correlation free. We are showing that: i) the arbitrary phase difference between the unsynchronized oscillator and injected synchronization signal is collapsed into two random and stable phases under subharmonic injection locking (SHIL); ii) the quantized oscillator phases under SHIL are fully symmetric and memoryless, generating bias and correlation free random bits; iii) the proposed oscillator phase TRNG is a generic design, independent of the oscillator platform. Thus, a CMOS ring oscillator based TRNG is also designed and evaluated. All of the generated random numbers pass the National Institute of Standards and Technology (NIST) tests and exhibit negligible bias and correlation from statistical analysis. Therefore, the proposed solution provides a competitive alternative to the existing on-chip TRNG design toolbox.