[openssl-dev] DRBG entropy

[Leon Brits]

John,

Thanks for your reply.

The SP800-90B test has different types of test but the test with the lowest output is used as the maximum entropy capability of the chip. That is how I understand it from the FIPS lab.

For the FIPS validation, using a NDRNG, that source must feed the DRBG directly (FIPS lab) and not from something like the PRNG. I use seed the /dev/random from the NDRNG and then source from the PRNG, but that is not allowed for DRBGs. Again I hope I understand them correct.

They said I must look at the OpenSSL user guide v2.0 para 6.1.1 where low entropy sources are discussed. Now, I already make use of the "get_entropy" function for my DRBG implementation. I use to source from the PRNG in that callback. I must now get it directly from my entropy source, which give rise to my question of how to ensure that I have high entropy of data before the callback exits.

Regards,
LJB