[Cryptography] Fast-key-erasure RNG and fork()ing

[Yann Droneaud]

Hi,

Le vendredi 29 juin 2018 à 00:46 +0200, Yann Ylavic a écrit :
> while "/dev/urandom" never blocks but doesn't garanty good randoms
> either 

Linux's /dev/urandom is a CSPRNG: it's designed to be cryptographically
strong. If correctly initialized, it garanties "good randoms".

https://www.2uo.de/myths-about-urandom

http://man7.org/linux/man-pages/man7/random.7.html
http://man7.org/linux/man-pages/man4/urandom.4.html

> (w/o enough entropy, how could it), 

That's one drawback of /dev/urandom versus getrandom(): without
GRND_RANDOM, the syscall might block when called early after kernel
boot, as the underlying CSPRNG will wait for some entropy to be
gathered. Once initialized, it should like /dev/urandom.

> not to talk about mostly unusable "/dev/random" for modern needs of
> randoms.

Except for long term keys, one should not need "/dev/random".

Regards.

-- 
Yann Droneaud
OPTEYA