add crypto_cs testing and benchmark

3 files changed, 731 insertions, 0 deletions

diff --git a/src/util/Makefile.am b/src/util/Makefile.am
index 771be1ee3..9fda40f51 100644
--- a/src/util/Makefile.am
+++ b/src/util/Makefile.am
@@ -254,6 +254,7 @@ libgnunet_plugin_utiltest_la_LDFLAGS = \
 
 if HAVE_BENCHMARKS
  BENCHMARKS = \
+  perf_crypto_cs \
   perf_crypto_hash \
   perf_crypto_rsa \
   perf_crypto_paillier \
@@ -290,6 +291,7 @@ check_PROGRAMS = \
  test_container_heap \
  test_crypto_symmetric \
  test_crypto_crc \
+ test_crypto_cs \
  test_crypto_ecdsa \
  test_crypto_eddsa \
  test_crypto_ecdhe \
@@ -450,6 +452,12 @@ test_crypto_crc_SOURCES = \
 test_crypto_crc_LDADD = \
  libgnunetutil.la
 
+test_crypto_cs_SOURCES = \
+ test_crypto_cs.c
+test_crypto_cs_LDADD = \
+ libgnunetutil.la \
+ -lsodium
+
 test_crypto_ecdsa_SOURCES = \
  test_crypto_ecdsa.c
 test_crypto_ecdsa_LDADD = \
@@ -605,6 +613,11 @@ test_uri_SOURCES = \
 test_uri_LDADD = \
  libgnunetutil.la
 
+perf_crypto_cs_SOURCES = \
+ perf_crypto_cs.c
+perf_crypto_cs_LDADD = \
+ libgnunetutil.la
+
 perf_crypto_hash_SOURCES = \
  perf_crypto_hash.c
 perf_crypto_hash_LDADD = \
diff --git a/src/util/perf_crypto_cs.c b/src/util/perf_crypto_cs.c
new file mode 100644
index 000000000..a8c72052b
--- /dev/null
+++ b/src/util/perf_crypto_cs.c
@@ -0,0 +1,185 @@
+/*
+     This file is part of GNUnet.
+     Copyright (C) 2014 GNUnet e.V.
+
+     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
+     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/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+
+/**
+ * @author Lucien Heuzeveldt <lucienclaude.heuzeveldt@students.bfh.ch>
+ * @author Gian Demarmels <gian@demarmels.org>
+ * @file util/perf_crypto_cs.c
+ * @brief measure performance of Clause Blind Schnorr Signatures
+ */
+
+#include "platform.h"
+#include "gnunet_util_lib.h"
+#include <gauger.h>
+
+#define ITER 10
+
+/**
+ * Evaluate Clause Blind Schnorr Signature performance.
+ *
+ */
+static void
+eval ()
+{
+  struct GNUNET_TIME_Absolute start;
+  unsigned int i;
+
+  struct GNUNET_CRYPTO_CsPrivateKey priv;
+  struct GNUNET_CRYPTO_CsPublicKey pub;
+
+  struct GNUNET_CRYPTO_CsRSecret r_priv[2];
+  struct GNUNET_CRYPTO_CsRPublic r_pub[2];
+
+  char message[] = "test message";
+  size_t message_len = strlen ("test message");
+
+  // derive a test nonce
+  struct GNUNET_CRYPTO_CsNonce nonce;
+  GNUNET_assert (GNUNET_YES == GNUNET_CRYPTO_hkdf (nonce.nonce,
+                                                   sizeof(nonce.nonce),
+                                                   GCRY_MD_SHA512,
+                                                   GCRY_MD_SHA256,
+                                                   "nonce",
+                                                   strlen ("nonce"),
+                                                   "nonce_secret",
+                                                   strlen ("nonce_secret"),
+                                                   NULL,
+                                                   0));
+
+  struct GNUNET_CRYPTO_CsBlindingSecret bs[2];
+  struct GNUNET_CRYPTO_CsC blinded_cs[2];
+  struct GNUNET_CRYPTO_CsRPublic blinded_r_pub[2];
+  struct GNUNET_CRYPTO_CsBlindS blinded_s;
+  struct GNUNET_CRYPTO_CsS signature_scalar;
+  struct GNUNET_CRYPTO_CsSignature sig;
+
+  // BENCHMARK keygen
+  start = GNUNET_TIME_absolute_get ();
+
+  for (i = 0; i < ITER; i++)
+  {
+    GNUNET_CRYPTO_cs_private_key_generate (&priv);
+    GNUNET_CRYPTO_cs_private_key_get_public (&priv, &pub);
+  }
+  printf ("10x key generation took %s\n",
+          GNUNET_STRINGS_relative_time_to_string (
+            GNUNET_TIME_absolute_get_duration (start),
+            GNUNET_YES));
+
+
+  // BENCHMARK r derive and calc R pub
+  start = GNUNET_TIME_absolute_get ();
+  for (i = 0; i < ITER; i++)
+  {
+    GNUNET_CRYPTO_cs_r_derive (&nonce, &priv, r_priv);
+    GNUNET_CRYPTO_cs_r_get_public (&r_priv[0], &r_pub[0]);
+    GNUNET_CRYPTO_cs_r_get_public (&r_priv[1], &r_pub[1]);
+  }
+  printf ("10x r0, r1 derive and R1,R2 calculation took %s\n",
+          GNUNET_STRINGS_relative_time_to_string (
+            GNUNET_TIME_absolute_get_duration (start),
+            GNUNET_YES));
+
+
+  // BENCHMARK derive blinding secrets
+  start = GNUNET_TIME_absolute_get ();
+  for (i = 0; i < ITER; i++)
+  {
+    GNUNET_CRYPTO_cs_blinding_secrets_derive (&nonce,
+                                              sizeof(struct
+                                                     GNUNET_CRYPTO_CsNonce),
+                                              bs);
+  }
+  printf ("10x derive blinding secrets took %s\n",
+          GNUNET_STRINGS_relative_time_to_string (
+            GNUNET_TIME_absolute_get_duration (start),
+            GNUNET_YES));
+
+
+  // BENCHMARK calculating C
+  start = GNUNET_TIME_absolute_get ();
+  for (i = 0; i < ITER; i++)
+  {
+    GNUNET_CRYPTO_cs_calc_blinded_c (bs,
+                                     r_pub,
+                                     &pub,
+                                     message,
+                                     message_len,
+                                     blinded_cs,
+                                     blinded_r_pub);
+  }
+  printf ("10x calculating the blinded c took %s\n",
+          GNUNET_STRINGS_relative_time_to_string (
+            GNUNET_TIME_absolute_get_duration (start),
+            GNUNET_YES));
+
+
+  // BENCHMARK sign derive
+  unsigned int b;
+  start = GNUNET_TIME_absolute_get ();
+  for (i = 0; i < ITER; i++)
+  {
+    b = GNUNET_CRYPTO_cs_sign_derive (&priv,
+                                      r_priv,
+                                      blinded_cs,
+                                      &nonce,
+                                      &blinded_s);
+  }
+  printf ("10x signing blinded c took %s\n",
+          GNUNET_STRINGS_relative_time_to_string (
+            GNUNET_TIME_absolute_get_duration (start),
+            GNUNET_YES));
+
+
+  // BENCHMARK unblind signature
+  start = GNUNET_TIME_absolute_get ();
+
+  for (i = 0; i < ITER; i++)
+  {
+    GNUNET_CRYPTO_cs_unblind (&blinded_s, &bs[b], &signature_scalar);
+    sig.r_point = blinded_r_pub[b];
+    sig.s_scalar = signature_scalar;
+  }
+  printf ("10x unblinding s took %s\n",
+          GNUNET_STRINGS_relative_time_to_string (
+            GNUNET_TIME_absolute_get_duration (start),
+            GNUNET_YES));
+
+  // BENCHMARK verify signature
+  start = GNUNET_TIME_absolute_get ();
+  for (i = 0; i < ITER; i++)
+  {
+    GNUNET_CRYPTO_cs_verify (&sig,
+                                   &pub,
+                                   message,
+                                   message_len);
+  }
+  printf ("10x verifying signatures took %s\n",
+          GNUNET_STRINGS_relative_time_to_string (
+            GNUNET_TIME_absolute_get_duration (start),
+            GNUNET_YES));
+}
+
+int
+main (int argc, char *argv[])
+{
+  eval ();
+  return 0;
+}
diff --git a/src/util/test_crypto_cs.c b/src/util/test_crypto_cs.c
new file mode 100644
index 000000000..2978fec0a
--- /dev/null
+++ b/src/util/test_crypto_cs.c
@@ -0,0 +1,533 @@
+/*
+   This file is part of GNUnet
+   Copyright (C) 2014,2015 GNUnet e.V.
+
+   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
+   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/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+
+/**
+ * @file util/test_crypto_cs.c
+ * @brief testcase for utility functions for clause blind schnorr signature scheme cryptography
+ * @author Lucien Heuzeveldt <lucienclaude.heuzeveldt@students.bfh.ch>
+ * @author Gian Demarmels <gian@demarmels.org>
+ */
+#include "platform.h"
+#include "gnunet_util_lib.h"
+#include <sodium.h>
+
+#define ITER 25
+
+void
+test_create_priv (struct GNUNET_CRYPTO_CsPrivateKey *priv)
+{
+  /* TEST 1
+   * Check that privkey is set
+   */
+  struct GNUNET_CRYPTO_CsPrivateKey other_priv;
+  memcpy (&other_priv.scalar, &priv->scalar, sizeof(other_priv.scalar));
+
+  GNUNET_CRYPTO_cs_private_key_generate (priv);
+
+  GNUNET_assert (0 != memcmp (&other_priv.scalar,
+                              &priv->scalar,
+                              sizeof(other_priv.scalar)));
+}
+
+
+void
+test_generate_pub (const struct GNUNET_CRYPTO_CsPrivateKey *priv,
+                       struct GNUNET_CRYPTO_CsPublicKey *pub)
+{
+  /* TEST 1
+   * Check that pubkey is set
+   */
+  struct GNUNET_CRYPTO_CsPublicKey other_pub;
+  memcpy (&other_pub.point, &pub->point, sizeof(other_pub.point));
+
+  GNUNET_CRYPTO_cs_private_key_get_public (priv, pub);
+
+  GNUNET_assert (0 != memcmp (&other_pub.point,
+                              &pub->point,
+                              sizeof(other_pub.point)));
+
+  /* TEST 2
+   * Check that pubkey is a valid point
+   */
+  GNUNET_assert (1 == crypto_core_ed25519_is_valid_point (pub->point.y));
+
+  /* TEST 3
+   * Check if function gives the same result for the same output
+   */
+  memcpy (&other_pub.point, &pub->point, sizeof(other_pub.point));
+
+  for (int i = 0; i<ITER; i++) {
+    GNUNET_CRYPTO_cs_private_key_get_public (priv, pub);
+    GNUNET_assert (0 == memcmp (&other_pub.point,
+                                &pub->point,
+                                sizeof(other_pub.point)));
+  }
+}
+
+
+void
+test_derive_rsecret (const struct GNUNET_CRYPTO_CsNonce *nonce,
+                   const struct GNUNET_CRYPTO_CsPrivateKey *priv,
+                   struct GNUNET_CRYPTO_CsRSecret r[2])
+{
+  /* TEST 1
+   * Check that r are set
+   */
+  struct GNUNET_CRYPTO_CsPrivateKey other_r[2];
+  memcpy (&other_r[0], &r[0], sizeof(struct GNUNET_CRYPTO_CsPrivateKey) * 2);
+
+  GNUNET_CRYPTO_cs_r_derive (nonce, priv, r);
+
+  GNUNET_assert (0 != memcmp (&other_r[0],
+                              &r[0],
+                              sizeof(struct GNUNET_CRYPTO_CsPrivateKey) * 2));
+
+  /* TEST 2
+   * Check if function gives the same result for the same input.
+   * This test ensures that the derivation is deterministic.
+   */
+  memcpy (&other_r[0], &r[0], sizeof(struct GNUNET_CRYPTO_CsPrivateKey) * 2);
+  for (int i = 0; i<ITER; i++) {
+    GNUNET_CRYPTO_cs_r_derive (nonce, priv, r);
+    GNUNET_assert (0 == memcmp (&other_r[0],
+                                &r[0],
+                                sizeof(struct GNUNET_CRYPTO_CsPrivateKey) * 2));
+  }
+}
+
+
+void
+test_generate_rpublic (const struct GNUNET_CRYPTO_CsRSecret *r_priv,
+                     struct GNUNET_CRYPTO_CsRPublic *r_pub)
+{
+  /* TEST 1
+   * Check that r_pub is set
+   */
+  struct GNUNET_CRYPTO_CsRPublic other_r_pub;
+  memcpy (&other_r_pub.point, &r_pub->point, sizeof(other_r_pub.point));
+
+  GNUNET_CRYPTO_cs_r_get_public (r_priv, r_pub);
+
+  GNUNET_assert (0 != memcmp (&other_r_pub.point,
+                              &r_pub->point,
+                              sizeof(other_r_pub.point)));
+
+  /* TEST 2
+   * Check that r_pub is a valid point
+   */
+  GNUNET_assert (1 == crypto_core_ed25519_is_valid_point (r_pub->point.y));
+
+  /* TEST 3
+   * Check if function gives the same result for the same output
+   */
+  memcpy (&other_r_pub.point, &r_pub->point, sizeof(other_r_pub.point));
+  for (int i = 0; i<ITER; i++) {
+    GNUNET_CRYPTO_cs_r_get_public (r_priv, r_pub);
+    GNUNET_assert (0 == memcmp (&other_r_pub.point,
+                                &r_pub->point,
+                                sizeof(other_r_pub.point)));
+  }
+}
+
+
+void
+test_derive_blindingsecrets (const void *secret,
+                           size_t secret_len,
+                           struct GNUNET_CRYPTO_CsBlindingSecret bs[2])
+{
+  /* TEST 1
+   * Check that blinding secrets are set
+   */
+  struct GNUNET_CRYPTO_CsBlindingSecret other_bs[2];
+  memcpy (&other_bs[0], &bs[0], sizeof(struct GNUNET_CRYPTO_CsBlindingSecret)
+          * 2);
+
+  GNUNET_CRYPTO_cs_blinding_secrets_derive (secret, secret_len, bs);
+
+  GNUNET_assert (0 != memcmp (&other_bs[0],
+                              &bs[0],
+                              sizeof(struct GNUNET_CRYPTO_CsBlindingSecret)
+                              * 2));
+
+  /* TEST 2
+   * Check if function gives the same result for the same input.
+   * This test ensures that the derivation is deterministic.
+   */
+  memcpy (&other_bs[0], &bs[0], sizeof(struct GNUNET_CRYPTO_CsBlindingSecret)
+          * 2);
+  for (int i = 0; i<ITER; i++) {
+    GNUNET_CRYPTO_cs_blinding_secrets_derive (secret, secret_len, bs);
+    GNUNET_assert (0 == memcmp (&other_bs[0],
+                                &bs[0],
+                                sizeof(struct GNUNET_CRYPTO_CsBlindingSecret)
+                                * 2));
+  }
+}
+
+
+void
+test_calc_blindedc (const struct GNUNET_CRYPTO_CsBlindingSecret bs[2],
+                  const struct GNUNET_CRYPTO_CsRPublic r_pub[2],
+                  const struct GNUNET_CRYPTO_CsPublicKey *pub,
+                  const void *msg,
+                  size_t msg_len,
+                  struct GNUNET_CRYPTO_CsC blinded_cs[2],
+                  struct GNUNET_CRYPTO_CsRPublic blinded_r_pub[2])
+{
+  /* TEST 1
+   * Check that the blinded c's and blinded r's
+   */
+  struct GNUNET_CRYPTO_CsC other_blinded_c[2];
+  memcpy (&other_blinded_c[0],
+          &blinded_cs[0],
+          sizeof(struct GNUNET_CRYPTO_CsC) * 2);
+
+  struct GNUNET_CRYPTO_CsRPublic other_blinded_r_pub[2];
+  memcpy (&other_blinded_r_pub[0],
+          &blinded_r_pub[0],
+          sizeof(struct GNUNET_CRYPTO_CsRPublic) * 2);
+
+  GNUNET_CRYPTO_cs_calc_blinded_c (bs,
+                                   r_pub,
+                                   pub,
+                                   msg,
+                                   msg_len,
+                                   blinded_cs,
+                                   blinded_r_pub);
+
+  GNUNET_assert (0 != memcmp (&other_blinded_c[0],
+                              &blinded_cs[0],
+                              sizeof(struct GNUNET_CRYPTO_CsC) * 2));
+  GNUNET_assert (0 != memcmp (&other_blinded_r_pub[0],
+                              &blinded_r_pub[0],
+                              sizeof(struct GNUNET_CRYPTO_CsRPublic) * 2));
+
+  /* TEST 2
+   * Check if R' - aG -bX = R for b = 0
+   * This test does the opposite operations and checks wether the equation is still correct.
+   */
+  for (unsigned int b = 0; b <= 1; b++) {
+    struct GNUNET_CRYPTO_Cs25519Point aG;
+    struct GNUNET_CRYPTO_Cs25519Point bX;
+    struct GNUNET_CRYPTO_Cs25519Point r_min_aG;
+    struct GNUNET_CRYPTO_CsRPublic res;
+
+    GNUNET_assert (0 == crypto_scalarmult_ed25519_base_noclamp (
+                     aG.y,
+                     bs[b].alpha.d));
+
+    GNUNET_assert (0 == crypto_scalarmult_ed25519_noclamp (
+                     bX.y,
+                     bs[b].beta.d,
+                     pub->point.y));
+
+    GNUNET_assert (0 == crypto_core_ed25519_sub (
+                     r_min_aG.y,
+                     blinded_r_pub[b].point.y,
+                     aG.y));
+
+    GNUNET_assert (0 == crypto_core_ed25519_sub (
+                     res.point.y,
+                     r_min_aG.y,
+                     bX.y));
+
+    GNUNET_assert (0 == memcmp (&res, &r_pub[b], sizeof(struct
+                                                        GNUNET_CRYPTO_CsRPublic)));
+  }
+
+
+
+  /* TEST 3
+   * Check that the blinded r_pubs' are valid points
+   */
+  GNUNET_assert (1 == crypto_core_ed25519_is_valid_point (
+                   blinded_r_pub[0].point.y));
+  GNUNET_assert (1 == crypto_core_ed25519_is_valid_point (
+                   blinded_r_pub[1].point.y));
+
+  /* TEST 4
+   * Check if function gives the same result for the same input.
+   */
+  memcpy (&other_blinded_c[0],
+          &blinded_cs[0],
+          sizeof(struct GNUNET_CRYPTO_CsC) * 2);
+  memcpy (&other_blinded_r_pub[0],
+          &blinded_r_pub[0],
+          sizeof(struct GNUNET_CRYPTO_CsRPublic) * 2);
+
+  for (int i = 0; i<ITER; i++) {
+    GNUNET_CRYPTO_cs_calc_blinded_c (bs,
+                                     r_pub,
+                                     pub,
+                                     msg,
+                                     msg_len,
+                                     blinded_cs,
+                                     blinded_r_pub);
+    GNUNET_assert (0 == memcmp (&other_blinded_c[0],
+                                &blinded_cs[0],
+                                sizeof(struct GNUNET_CRYPTO_CsC) * 2));
+    GNUNET_assert (0 == memcmp (&other_blinded_r_pub[0],
+                                &blinded_r_pub[0],
+                                sizeof(struct GNUNET_CRYPTO_CsRPublic) * 2));
+  }
+}
+
+
+void
+test_blind_sign (unsigned int *b,
+               const struct GNUNET_CRYPTO_CsPrivateKey *priv,
+               const struct GNUNET_CRYPTO_CsRSecret r[2],
+               const struct GNUNET_CRYPTO_CsC c[2],
+               const struct GNUNET_CRYPTO_CsNonce *nonce,
+               struct GNUNET_CRYPTO_CsBlindS *blinded_s)
+{
+  /* TEST 1
+   * Check that blinded_s is set
+   */
+  struct GNUNET_CRYPTO_CsC other_blinded_s;
+  memcpy (&other_blinded_s, blinded_s, sizeof(struct GNUNET_CRYPTO_CsBlindS));
+
+  *b = GNUNET_CRYPTO_cs_sign_derive (priv,
+                                     r,
+                                     c,
+                                     nonce,
+                                     blinded_s);
+
+  GNUNET_assert (0 == *b || 1 == *b);
+  GNUNET_assert (0 != memcmp (&other_blinded_s,
+                              blinded_s,
+                              sizeof(struct GNUNET_CRYPTO_CsBlindS)));
+
+  /* TEST 2
+   * Check if s := rb + cbX
+   * This test does the opposite operations and checks wether the equation is still correct.
+   */
+  struct GNUNET_CRYPTO_Cs25519Scalar cb_mul_x;
+  struct GNUNET_CRYPTO_Cs25519Scalar s_min_rb;
+
+  crypto_core_ed25519_scalar_mul (cb_mul_x.d,
+                                  c[*b].scalar.d,
+                                  priv->scalar.d);
+
+  crypto_core_ed25519_scalar_sub (s_min_rb.d,
+                                  blinded_s->scalar.d,
+                                  r[*b].scalar.d);
+
+  GNUNET_assert (0 == memcmp (&s_min_rb, &cb_mul_x, sizeof(struct
+                                                           GNUNET_CRYPTO_Cs25519Scalar)));
+
+  /* TEST 3
+   * Check if function gives the same result for the same input.
+   */
+  memcpy (&other_blinded_s, blinded_s, sizeof(struct GNUNET_CRYPTO_CsBlindS));
+  unsigned int other_b;
+  for (int i = 0; i<ITER; i++) {
+    other_b = GNUNET_CRYPTO_cs_sign_derive (priv, r, c, nonce, blinded_s);
+
+    GNUNET_assert (other_b == *b);
+    GNUNET_assert (0 == memcmp (&other_blinded_s,
+                                blinded_s,
+                                sizeof(struct GNUNET_CRYPTO_CsBlindS)));
+  }
+}
+
+
+void
+test_unblinds (const struct GNUNET_CRYPTO_CsBlindS *blinded_signature_scalar,
+              const struct GNUNET_CRYPTO_CsBlindingSecret *bs,
+              struct GNUNET_CRYPTO_CsS *signature_scalar)
+{
+  /* TEST 1
+   * Check that signature_scalar is set
+   */
+  struct GNUNET_CRYPTO_CsS other_signature_scalar;
+  memcpy (&other_signature_scalar,
+          signature_scalar,
+          sizeof(struct GNUNET_CRYPTO_CsS));
+
+  GNUNET_CRYPTO_cs_unblind (blinded_signature_scalar, bs, signature_scalar);
+
+  GNUNET_assert (0 != memcmp (&other_signature_scalar,
+                              signature_scalar,
+                              sizeof(struct GNUNET_CRYPTO_CsS)));
+
+  /* TEST 2
+   * Check if s' := s + a mod p
+   * This test does the opposite operations and checks wether the equation is still correct.
+   */
+  struct GNUNET_CRYPTO_Cs25519Scalar s_min_a;
+
+  crypto_core_ed25519_scalar_sub (s_min_a.d,
+                                  signature_scalar->scalar.d,
+                                  bs->alpha.d);
+
+  GNUNET_assert (0 == memcmp (&s_min_a, &blinded_signature_scalar->scalar,
+                              sizeof(struct
+                                     GNUNET_CRYPTO_Cs25519Scalar)));
+
+  /* TEST 3
+   * Check if function gives the same result for the same input.
+   */
+  memcpy (&other_signature_scalar, signature_scalar,
+          sizeof(struct GNUNET_CRYPTO_CsS));
+
+  for (int i = 0; i<ITER; i++) {
+    GNUNET_CRYPTO_cs_unblind (blinded_signature_scalar, bs, signature_scalar);
+    GNUNET_assert (0 == memcmp (&other_signature_scalar,
+                                signature_scalar,
+                                sizeof(struct GNUNET_CRYPTO_CsS)));
+  }
+}
+
+
+void
+test_blind_verify (const struct GNUNET_CRYPTO_CsSignature *sig,
+                 const struct GNUNET_CRYPTO_CsPublicKey *pub,
+                 const struct GNUNET_CRYPTO_CsC *c)
+{
+  /* TEST 1
+   * Test verifies the blinded signature sG == Rb + cbX
+   */
+  struct GNUNET_CRYPTO_Cs25519Point sig_scal_mul_base;
+  GNUNET_assert (0 == crypto_scalarmult_ed25519_base_noclamp (
+                   sig_scal_mul_base.y,
+                   sig->s_scalar.scalar.d));
+
+  struct GNUNET_CRYPTO_Cs25519Point c_mul_pub;
+  GNUNET_assert (0 == crypto_scalarmult_ed25519_noclamp (c_mul_pub.y,
+                                                         c->scalar.d,
+                                                         pub->point.y));
+
+  struct GNUNET_CRYPTO_Cs25519Point r_add_c_mul_pub;
+  GNUNET_assert (0 == crypto_core_ed25519_add (r_add_c_mul_pub.y,
+                                               sig->r_point.point.y,
+                                               c_mul_pub.y));
+
+  GNUNET_assert (0 == memcmp (sig_scal_mul_base.y,
+                              r_add_c_mul_pub.y,
+                              sizeof(struct GNUNET_CRYPTO_Cs25519Point)));
+}
+
+
+void
+test_verify (const struct GNUNET_CRYPTO_CsSignature *sig,
+            const struct GNUNET_CRYPTO_CsPublicKey *pub,
+            const void *msg,
+            size_t msg_len)
+{
+  /* TEST 1
+   * Test simple verification
+   */
+  GNUNET_assert (GNUNET_YES == GNUNET_CRYPTO_cs_verify (sig,
+                                                        pub,
+                                                        msg,
+                                                        msg_len));
+  /* TEST 2
+   * Test verification of "wrong" message
+   */
+  char other_msg[] = "test massege";
+  size_t other_msg_len = strlen ("test massege");
+  GNUNET_assert (GNUNET_SYSERR == GNUNET_CRYPTO_cs_verify (sig,
+                                                       pub,
+                                                       other_msg,
+                                                       other_msg_len));
+}
+
+
+int
+main (int argc,
+      char *argv[])
+{
+  printf ("Test started\n");
+
+  // ---------- actions performed by signer
+  char message[] = "test message";
+  size_t message_len = strlen ("test message");
+
+  struct GNUNET_CRYPTO_CsPrivateKey priv;
+  test_create_priv (&priv);
+
+  struct GNUNET_CRYPTO_CsPublicKey pub;
+  test_generate_pub (&priv, &pub);
+
+  // derive nonce
+  struct GNUNET_CRYPTO_CsNonce nonce;
+  GNUNET_assert (GNUNET_YES == GNUNET_CRYPTO_hkdf (nonce.nonce,
+                                                   sizeof(nonce.nonce),
+                                                   GCRY_MD_SHA512,
+                                                   GCRY_MD_SHA256,
+                                                   "nonce",
+                                                   strlen ("nonce"),
+                                                   "nonce_secret",
+                                                   strlen ("nonce_secret"),
+                                                   NULL,
+                                                   0));
+
+  // generate r, R
+  struct GNUNET_CRYPTO_CsRSecret r_secrets[2];
+  test_derive_rsecret (&nonce, &priv, r_secrets);
+
+  struct GNUNET_CRYPTO_CsRPublic r_publics[2];
+  test_generate_rpublic (&r_secrets[0], &r_publics[0]);
+  test_generate_rpublic (&r_secrets[1], &r_publics[1]);
+
+  // ---------- actions performed by user
+
+  // generate blinding secrets
+  struct GNUNET_CRYPTO_CsBlindingSecret blindingsecrets[2];
+  test_derive_blindingsecrets (&nonce,
+                             sizeof(nonce),
+                             blindingsecrets);
+
+  // calculate blinded c's
+  struct GNUNET_CRYPTO_CsC blinded_cs[2];
+  struct GNUNET_CRYPTO_CsRPublic blinded_r_pubs[2];
+  test_calc_blindedc (blindingsecrets,
+                    r_publics,
+                    &pub,
+                    message,
+                    message_len,
+                    blinded_cs,
+                    blinded_r_pubs);
+
+  // ---------- actions performed by signer
+  // sign blinded c's and get b and s in return
+  unsigned int b;
+  struct GNUNET_CRYPTO_CsBlindS blinded_s;
+  test_blind_sign (&b, &priv, r_secrets, blinded_cs, &nonce, &blinded_s);
+
+  // verify blinded signature
+  struct GNUNET_CRYPTO_CsSignature blinded_signature;
+  blinded_signature.r_point = r_publics[b];
+  blinded_signature.s_scalar.scalar = blinded_s.scalar;
+  test_blind_verify (&blinded_signature, &pub, &blinded_cs[b]);
+
+  // ---------- actions performed by user
+    struct GNUNET_CRYPTO_CsS sig_scalar;
+  test_unblinds (&blinded_s, &blindingsecrets[b], &sig_scalar);
+
+  // verify unblinded signature
+  struct GNUNET_CRYPTO_CsSignature signature;
+  signature.r_point = blinded_r_pubs[b];
+  signature.s_scalar = sig_scalar;
+  test_verify (&signature, &pub, message, message_len);
+
+  return 0;
+}