hmac_sha1
hmac_sha1(asalt, salt_len + 4, pass, pass_len, d1);
hmac_sha1(d1, sizeof(d1), pass, pass_len, d2);
void hmac_sha1(const u_int8_t *, size_t, const u_int8_t *,
hmac_sha1(asalt, salt_len + 4, pass, pass_len, d1);
hmac_sha1(d1, sizeof(d1), pass, pass_len, d2);
hmac_sha1(key, key_size, check_key, sizeof(check_key), check_digest);