/*
This file is part of GNUnet.
- Copyright (C) 2012, 2013, 2015 Christian Grothoff (and other contributing authors)
+ Copyright (C) 2012, 2013, 2015 GNUnet e.V.
GNUnet is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
*
* @param max maximum value the factor can be
* @param mem memory to use (should be smaller than @a max), must not be zero.
- * @return @a max if dlog failed, otherwise the factor
+ * @return NULL on error
*/
struct GNUNET_CRYPTO_EccDlogContext *
GNUNET_CRYPTO_ecc_dlog_prepare (unsigned int max,
*
* @param edc precalculated values, determine range of factors
* @param input point on the curve to factor
- * @return `edc->max` if dlog failed, otherwise the factor
+ * @return INT_MAX if dlog failed, otherwise the factor
*/
int
GNUNET_CRYPTO_ecc_dlog (struct GNUNET_CRYPTO_EccDlogContext *edc,
GNUNET_assert (NULL != g);
q = gcry_mpi_point_new (0);
- res = edc->max;
+ res = INT_MAX;
for (i=0;i<=edc->max/edc->mem;i++)
{
if (0 == i)
}
+/**
+ * Obtain a random scalar for point multiplication on the curve and
+ * its multiplicative inverse.
+ *
+ * @param edc calculation context for ECC operations
+ * @param[out] r set to a random scalar on the curve
+ * @param[out] r_inv set to the multiplicative inverse of @a r
+ */
+void
+GNUNET_CRYPTO_ecc_rnd_mpi (struct GNUNET_CRYPTO_EccDlogContext *edc,
+ gcry_mpi_t *r,
+ gcry_mpi_t *r_inv)
+{
+ gcry_mpi_t n;
+
+ *r = GNUNET_CRYPTO_ecc_random_mod_n (edc);
+ /* r_inv = n - r = - r */
+ *r_inv = gcry_mpi_new (0);
+ n = gcry_mpi_ec_get_mpi ("n", edc->ctx, 1);
+ gcry_mpi_sub (*r_inv, n, *r);
+}
+
+
/**
* Free a point value returned by the API.
*