Submitted by: Matthew D Wood
Reviewed by: Bodo Moeller

Note: the RAND_bytes() manual page says:
 RAND_bytes() puts num cryptographically strong pseudo-random bytes into buf.
It does not talk about using the previous contents of buf so we are working
as documented.

code checking tools.
PR: 1499

EVP_CIPHER_CTX structure which may not be the same as the underlying
cipher key length for variable length ciphers.