8.2 8Mb/s 28Mb/mJ robust true-random-number generator in 65nm CMOS based on differential ring oscillator with feedback resistors

On-chip true random number generators (TRNG) have been gaining attention as an important component for building secure systems [1]. CMOS TRNGs typically exploit device-level noise, such as thermal or flicker noise to generate random bits [2]. Among various types of CMOS TRNGs, the meta-stability-based TRNG is known to have very high throughput for random bit generation, but it requires sophisticated control and calibration circuits to suppress bias [6]. Another popular type is the ring oscillator (RO)-based TRNG, which utilizes timing jitter [1–5]. Relatively simple circuits make it an attractive option, but there remains a need to improve the tolerance against power supply attacks and process/environmental variations [3]. Recently, selective use of a certain set of inverter chains based on pre-tuning was proposed to mitigate process variation effects [2].