src: for every AGPL3.0 file, add SPDX identifier.

[oweals/gnunet.git] / src / util / crypto_ecc_dlog.c

diff --git a/src/util/crypto_ecc_dlog.c b/src/util/crypto_ecc_dlog.c
index 29cba3336faf8d64df23c7e1beebcc0f30b47ac9..07777e377d562fdd8e5cb42b9c1515e1c1f8c7a5 100644 (file)
--- a/src/util/crypto_ecc_dlog.c
+++ b/src/util/crypto_ecc_dlog.c
@@ -1,21 +1,21 @@
 /*
      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
-     by the Free Software Foundation; either version 3, or (at your
-     option) any later version.
+     GNUnet is free software: you can redistribute it and/or modify it
+     under the terms of the GNU Affero General Public License as published
+     by the Free Software Foundation, either version 3 of the License,
+     or (at your option) any later version.
 
      GNUnet is distributed in the hope that it will be useful, but
      WITHOUT ANY WARRANTY; without even the implied warranty of
      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-     General Public License for more details.
+     Affero General Public License for more details.
+    
+     You should have received a copy of the GNU Affero General Public License
+     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-     You should have received a copy of the GNU General Public License
-     along with GNUnet; see the file COPYING.  If not, write to the
-     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-     Boston, MA 02111-1307, USA.
+     SPDX-License-Identifier: AGPL3.0-or-later
 */
 
 /**
@@ -130,6 +130,7 @@ GNUNET_CRYPTO_ecc_bin_to_point (struct GNUNET_CRYPTO_EccDlogContext *edc,
   gcry_ctx_t ctx;
   gcry_mpi_point_t q;
 
+  (void) edc;
   if (0 != gcry_sexp_build (&pub_sexpr, NULL,
                             "(public-key(ecc(curve " CURVE ")(q %b)))",
                             (int) sizeof (bin->q_y),
@@ -151,7 +152,7 @@ GNUNET_CRYPTO_ecc_bin_to_point (struct GNUNET_CRYPTO_EccDlogContext *edc,
  *
  * @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,
@@ -219,7 +220,7 @@ 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,
@@ -237,7 +238,7 @@ 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)
@@ -466,6 +467,29 @@ GNUNET_CRYPTO_ecc_rnd (struct GNUNET_CRYPTO_EccDlogContext *edc,
 }
 
 
+/**
+ * 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.
  *