Re: Question - seeding the hw pseudo random number generator

On Mon, Mar 20, 2017 at 09:28:58PM +0800, Herbert Xu wrote:

On Mon, Mar 20, 2017 at 12:19:32PM +0530, PrasannaKumar Muralidharan wrote:

quoted

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.

The actual hardware block can be seeded from true RNG (taking data
from thermal noise) so the solutions (if I understand correctly) for
exynos-rng might be:
1. Seed from internal TRNG making it a proper hwrandom device,
2. Convert to AF_ALG and seed with data from user-space through that
   interface.

Thanks for explanation, I'll queue it to my tasks list.

Best regards,
Krzysztof