=back
-=head1 Random numbers
-
-The following can be used to select the DRBG that is used to generate the random
-numbers:
-
-EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_SET_DRBG, 0, drbg)
-
-The following can be used to get the DRBG:
-
-EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GET_DRBG, 0, &drbg)
-
-By default it's set to NULL which results in RAND_bytes() being used.
-
-
=head1 NOTES
Where possible the B<EVP> interface to symmetric ciphers should be used in