Another entropy source that has shown promise is random telegraph noise (RTN). RTN is a phenomenon observed in scaled CMOS devices caused by the capture and emission of charge carriers from the conduction channel to traps within the gate dielectric that results in variation of the threshold voltage and channel current over time. The variation in the capture and emission time can be extracted and used as an entropy source. Several RTN-based TRNG designs have been proposed, however all have drawbacks of low speed, complex tuning requirements, complex post-processing, vulnerability to over-sampling attacks, or the need for large device arrays to find a device with suitable RTN to be used as an entropy source.

Abe, K., Teramoto, A., Sugawa, S. & Ohmi, T. Understanding of traps causing random telegraph noise based on experimentally extracted time constants and amplitude. 2, 4A.4.1-4A.4.6 (2011).
Was Reveal Random? Did Telegraph Death? Was Sex Good for You? Ballsy ? And More Qs!

















