fatal("%s: bad host modulus (len %d)", __func__, len);
BN_bn2bin(host_modulus, nbuf);
EVP_DigestUpdate(&md, nbuf, len);
len = BN_num_bytes(server_modulus);
fatal("%s: bad host modulus (len %d)", __func__, len);
BN_bn2bin(host_modulus, nbuf);
EVP_DigestUpdate(&md, nbuf, len);
len = BN_num_bytes(server_modulus);