4 ms·
It absolutely is possible to generate entropy on-die, assuming you actually want entropy and not just a unique value that gets XORed with the seed, so you can s
by eternityforest 3y ago
It absolutely is possible to generate entropy on-die, assuming you actually want entropy and not just a unique value that gets XORed with the seed, so you can still have repeatable seeds.
Pretty much every chip has an RNG which can be as simple as just a single free running oscillator you sample
- lelanthran 3y ago> Pretty much every chip has an RNG which can be as simple as just a single free running oscillator you sample Every chip may have some sort of noise to sample, but they are nowhere near good sources of entropy. Entropy is not a binary thing (you either have it or don't), it's a spectrum and entropy gathered on-die is poor entropy. Look, I concede that my knowledge on this subject is a bit dated, but the last time I checked there were no good sources of entropy on-die for any chip in wide use. All cryptographically secure RNGs depend on a peripheral to grab noise from the environment to mix into the entropy pool. A free-running oscillator is a very poor source of entropy.
- eternityforest 3y agoFor non-cryptographic applications, a PRNG like xorshift reseeded by a few bits from an oscillator might be enough. As I understand it, the reason they don't use on-chip RNGs by themselves isn't due to lack of entropy, it's because people don't trust them not to put a backdoor on the chips or to have some kind of bug. Intel has https://en.m.wikipedia.org/wiki/RDRAND https://en.m.wikipedia.org/wiki/RDRAND but almost all chips seem to now have some kind of RNG.