int ssh_kdf(struct ssh_crypto_struct *crypto,
            unsigned char *key, size_t key_len,
            int key_type, unsigned char *output,
            size_t requested_len)
{
    return sshkdf_derive_key(crypto, key, key_len,
                             key_type, output, requested_len);
}
int ssh_kdf(struct ssh_crypto_struct *crypto,
            unsigned char *key, size_t key_len,
            int key_type, unsigned char *output,
            size_t requested_len)
{
    return sshkdf_derive_key(crypto, key, key_len,
                             key_type, output, requested_len);
}