Description
Introduction
- Measuring the thermal component of clock jitter as an entropy source for True Random Number Generators (TRNGs) is compulsory for the security and evaluation of clock-jitter based TRNGs. However, identifying and isolating the local thermal noise component from other noise sources, particularly flicker noise, while performing a precise measurement remains a challenge.
Current Techniques
- We present an overview of the most effective techniques currently available for measuring the thermal clock jitter component. However, even the best techniques may struggle to avoid the influence of flicker noise on their measurements. Consequently, their results risk representing an overestimation of the thermal jitter component.
Characterizing Clock Jitter
- We present state-of-the-art methods for distinguishing between flicker noise and thermal noise components of a random signal while introducing their problems when applied to the evaluation of TRNGs.
Conclusion
- Despite advancements, current clock jitter measurement techniques should be used cautiously.