[openssl-dev] Work on a new RNG for OpenSSL

[Salz, Rich]

> I think we can get away with using OS-provided randomness directly in many common cases.  /dev/urandom suffices once we know that the kernel RNG has been properly seeded.  On FreeBSD, /dev/urandom blocks until the kernel RNG is seeded; on other systems maybe we have to make one read from /dev/random to get the blocking behavior we want before switching to /dev/urandom for bulk reads.

It's not a question of "get away with." 

If the O/S libraries provides random bytes, like CryptGenRandom in windows or arc4random() then we should just wrap those functions and use them by default.  If the O/S kernel provides random bytes, then we should use those bytes to seed (and to reseed) for a DRBG generator.

We should allow applications to save/restore state, such as on reboot.