Hi, On 2022-12-05 14:13, Jason A. Donenfeld wrote: > On Mon, Nov 28, 2022 at 07:47:17PM +0100, Aurelien Jarno wrote: > > The TRNG device does not seem to have a signal conditionner and the FIPS > > 140-2 test returns a lot of failures. They can be reduced by increasing > > RK_RNG_SAMPLE_CNT, in a tradeoff between quality and speed. This value > > has been adjusted to get ~90% of successes and the quality value has > > been set accordingly. > > Can't you reduce it even more to get 100%? All we need is 32 bytes every > once in a while. >From what I understood, we get the raw stream of the TRNG, there is no conditionner and the TRNG is not FIPS compliant. So even with the slowest speed, you don't reach 100% and you only get a very small increase in the quality while it's way more slower. > > + rk_rng->rng.quality = 900; > > If your intention is "90%", this should be 921 or 922, because the > quality knob is out of 1024, not 1000. Well I am not sure it really matters. 90% is actually conservative, it's the worst case I have seen, rounded down. However I often get much better quality, see for instance the following run: | Copyright (c) 2004 by Henrique de Moraes Holschuh | This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. | | rngtest: starting FIPS tests... | rngtest: entropy source drained | rngtest: bits received from input: 16777216 | rngtest: FIPS 140-2 successes: 819 | rngtest: FIPS 140-2 failures: 19 | rngtest: FIPS 140-2(2001-10-10) Monobit: 17 | rngtest: FIPS 140-2(2001-10-10) Poker: 0 | rngtest: FIPS 140-2(2001-10-10) Runs: 2 | rngtest: FIPS 140-2(2001-10-10) Long run: 2 | rngtest: FIPS 140-2(2001-10-10) Continuous run: 0 | rngtest: input channel speed: (min=132.138; avg=137.848; max=147.308)Kibits/s | rngtest: FIPS tests speed: (min=16.924; avg=20.272; max=20.823)Mibits/s | rngtest: Program run time: 119647459 microseconds Does the exact value has an importance there? I thought it was just important to not overestimate the quality. Regards Aurelien -- Aurelien Jarno GPG: 4096R/1DDD8C9B aurelien@xxxxxxxxxxx http://www.aurel32.net
