Question - seeding the hw pseudo random number generator

Stephan Müller
2017-03-20T13:39:47Z

Am Montag, 20. M?rz 2017, 14:28:58 CET schrieb Herbert Xu:

Hi Herbert,

> On Mon, Mar 20, 2017 at 12:19:32PM +0530, PrasannaKumar Muralidharan wrote:
> > AF_ALG interface for rng does have seeding support. I think hw_random
> > does not provide seeding support intentionally as I understand that
> > True RNG need not require seeding (please correct me if I am wrong).
>
> Yes. We should be converting PRNGs in hwrng over to algif_rng.

IMHO this not only applies to the PRNGs in drivers/crypto (which should simply
register with crypto_register_rngs) but also to ~/hacking/sources/linux/arch/
s390/crypto/prng.c which exports a /dev/prandom file.

For the seeding, it may make sense to follow the example given with crypto/
drbg.c using the add_random_ready_callback function.

Ciao
Stephan