Ejemplos de _gnutls_mpi_subm en C++ (Cpp)

Ejemplo n.º 1

Archivo: gnutls_srp.c Proyecto: ares89/vlc

/* S = (B - k*g^x) ^ (a + u * x) % N
 * this is our shared key (client premaster secret)
 */
bigint_t
_gnutls_calc_srp_S2 (bigint_t B, bigint_t g, bigint_t x, bigint_t a,
                     bigint_t u, bigint_t n)
{
  bigint_t S = NULL, tmp1 = NULL, tmp2 = NULL;
  bigint_t tmp4 = NULL, tmp3 = NULL, k = NULL;

  S = _gnutls_mpi_alloc_like (n);
  if (S == NULL)
    return NULL;

  tmp1 = _gnutls_mpi_alloc_like (n);
  tmp2 = _gnutls_mpi_alloc_like (n);
  tmp3 = _gnutls_mpi_alloc_like (n);
  if (tmp1 == NULL || tmp2 == NULL || tmp3 == NULL)
    {
      goto freeall;
    }

  k = _gnutls_calc_srp_u (n, g, n);
  if (k == NULL)
    {
      gnutls_assert ();
      goto freeall;
    }

  _gnutls_mpi_powm (tmp1, g, x, n);     /* g^x */
  _gnutls_mpi_mulm (tmp3, tmp1, k, n);  /* k*g^x mod n */
  _gnutls_mpi_subm (tmp2, B, tmp3, n);

  tmp4 = _gnutls_mpi_alloc_like (n);
  if (tmp4 == NULL)
    goto freeall;

  _gnutls_mpi_mul (tmp1, u, x);
  _gnutls_mpi_add (tmp4, a, tmp1);
  _gnutls_mpi_powm (S, tmp2, tmp4, n);

  _gnutls_mpi_release (&tmp1);
  _gnutls_mpi_release (&tmp2);
  _gnutls_mpi_release (&tmp3);
  _gnutls_mpi_release (&tmp4);
  _gnutls_mpi_release (&k);

  return S;

freeall:
  _gnutls_mpi_release (&k);
  _gnutls_mpi_release (&tmp1);
  _gnutls_mpi_release (&tmp2);
  _gnutls_mpi_release (&tmp3);
  _gnutls_mpi_release (&tmp4);
  _gnutls_mpi_release (&S);
  return NULL;
}

Ejemplo n.º 2

Archivo: srp.c Proyecto: attilamolnar/gnutls

/* S = (B - k*g^x) ^ (a + u * x) % N
 * this is our shared key (client premaster secret)
 */
bigint_t
_gnutls_calc_srp_S2(bigint_t B, bigint_t g, bigint_t x, bigint_t a,
		    bigint_t u, bigint_t n)
{
	bigint_t S = NULL, tmp1 = NULL, tmp2 = NULL;
	bigint_t tmp4 = NULL, tmp3 = NULL, k = NULL;
	int ret;

	ret = _gnutls_mpi_init_multi(&S, &tmp1, &tmp2, &tmp3, &tmp4, NULL);
	if (ret < 0)
		return NULL;

	k = _gnutls_calc_srp_u(n, g, n);
	if (k == NULL) {
		gnutls_assert();
		goto freeall;
	}

	ret = _gnutls_mpi_powm(tmp1, g, x, n);	/* g^x */
	if (ret < 0) {
		gnutls_assert();
		goto freeall;
	}

	ret = _gnutls_mpi_mulm(tmp3, tmp1, k, n);	/* k*g^x mod n */
	if (ret < 0) {
		gnutls_assert();
		goto freeall;
	}

	ret = _gnutls_mpi_subm(tmp2, B, tmp3, n);
	if (ret < 0) {
		gnutls_assert();
		goto freeall;
	}

	ret = _gnutls_mpi_mul(tmp1, u, x);
	if (ret < 0) {
		gnutls_assert();
		goto freeall;
	}

	ret = _gnutls_mpi_add(tmp4, a, tmp1);
	if (ret < 0) {
		gnutls_assert();
		goto freeall;
	}

	ret = _gnutls_mpi_powm(S, tmp2, tmp4, n);
	if (ret < 0) {
		gnutls_assert();
		goto freeall;
	}

	_gnutls_mpi_release(&tmp1);
	_gnutls_mpi_release(&tmp2);
	_gnutls_mpi_release(&tmp3);
	_gnutls_mpi_release(&tmp4);
	_gnutls_mpi_release(&k);

	return S;

      freeall:
	_gnutls_mpi_release(&k);
	_gnutls_mpi_release(&tmp1);
	_gnutls_mpi_release(&tmp2);
	_gnutls_mpi_release(&tmp3);
	_gnutls_mpi_release(&tmp4);
	_gnutls_mpi_release(&S);
	return NULL;
}