rsa_compute_root_tr(const struct rsa_public_key *pub,
		    const struct rsa_private_key *key,
		    void *random_ctx, nettle_random_func *random,
		    mpz_t x, const mpz_t m)
{
  int res;
  mpz_t t, mb, xb, ri;

  mpz_init (mb);
  mpz_init (xb);
  mpz_init (ri);
  mpz_init (t);

  rsa_blind (pub, random_ctx, random, mb, ri, m);

  rsa_compute_root (key, xb, mb);

  mpz_powm_sec(t, xb, pub->e, pub->n);
  res = (mpz_cmp(mb, t) == 0);

  if (res)
    rsa_unblind (pub, x, ri, xb);

  mpz_clear (mb);
  mpz_clear (xb);
  mpz_clear (ri);
  mpz_clear (t);

  return res;
}
The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor, which exposes security-relevant information about the state of the product, such as whether a particular operation was successful or not.