How to seed PRNG for usage with BN_rand*?

Question

I would like to use:

BN_rand_range(...);

and due to the OpenSSL documentation:

The PRNG must be seeded prior to calling BN_rand() or BN_rand_range().

But there is no link or method name hint provided how I could do that. What is the correct way to seed the PRNG with OpenSSL?

Answer 1

What is the correct way to seed the PRNG with OpenSSL?

Internally, OpenSSL of auto-seeds itself with RAND_poll (with some hand waiving). There's a few reasons why you might want to avoid the behavior and explicitly seed the generator yourself.

There's a more complete writeup on the OpenSSL wiki at Random Numbers.