bool silc_pkcs_verify_with_hash(SilcPKCS pkcs, SilcHash hash,
                                    unsigned char *signature,
                                    SilcUInt32 signature_len,
                                    unsigned char *data,
                                    SilcUInt32 data_len);

    Verifies signature with hash.  The `data' is hashed and verified against
    the `signature'.  Returns FALSE on error.