private key B<rsa> as specified in PKCS #1 v2.0. It stores the
signature in B<sigret> and the signature size in B<siglen>. B<sigret>
must point to RSA_size(B<rsa>) bytes of memory.
private key B<rsa> as specified in PKCS #1 v2.0. It stores the
signature in B<sigret> and the signature size in B<siglen>. B<sigret>
must point to RSA_size(B<rsa>) bytes of memory.