content: Noisy junctions in semiconductors can be used as an entropy source for random number generation. I've seen several projects use this normally unwanted feature to generate strong randomness. I've also seen CMOS image sensors from cheap webcams used where they block all visible light from the sensor and let it fire randomly from noise, but these usually end up with some pseudo-random artifacts due to thermal gradients. The semiconductor junction method can probably overcome most of this as it is a single source rather than thousands or millions of junctions like the camera sensor. There's a RNG device based on this on Tindie that uses this noisy junction to provide an entropy pool for Linux. Note: I'm not the seller or affiliated with the seller/Tindie