add missing file

src/util/denom.c

@@ -0,0 +1,115 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2021 Taler Systems SA
+
+  TALER 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.
+
+  TALER 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.
+
+  You should have received a copy of the GNU General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file denom.c
+ * @brief denomination utility functions
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "taler_util.h"
+
+
+void
+TALER_denom_pub_hash (const struct TALER_DenominationPublicKey *denom_pub,
+                      struct TALER_DenominationHash *denom_hash)
+{
+  uint32_t opt[2] = {
+    htonl (denom_pub->age_mask),
+    htonl ((uint32_t) denom_pub->cipher)
+  };
+
+  struct GNUNET_HashContext *hc;
+  hc = GNUNET_CRYPTO_hash_context_start ();
+  GNUNET_CRYPTO_hash_context_read (hc,
+                                   opt,
+                                   sizeof (opt));
+  switch (denom_pub->cipher)
+  {
+  case TALER_DENOMINATION_RSA:
+    {
+      void *buf;
+      size_t blen;
+
+      blen = GNUNET_CRYPTO_rsa_public_key_encode (
+        denom_pub->details.rsa_public_key,
+        &buf);
+      GNUNET_CRYPTO_hash_context_read (hc,
+                                       buf,
+                                       blen);
+      GNUNET_free (buf);
+    }
+    break;
+  // TODO: add case for Clause-Schnorr
+  default:
+    GNUNET_assert (0);
+  }
+  GNUNET_CRYPTO_hash_context_finish (hc,
+                                     &denom_hash->hash);
+}
+
+
+void
+TALER_denom_priv_to_pub (const struct TALER_DenominationPrivateKey *denom_priv,
+                         uint32_t age_mask,
+                         struct TALER_DenominationPublicKey *denom_pub)
+{
+  switch (denom_priv->cipher)
+  {
+  case TALER_DENOMINATION_RSA:
+    denom_pub->cipher = TALER_DENOMINATION_RSA;
+    denom_pub->age_mask = age_mask;
+    denom_pub->details.rsa_public_key
+      = GNUNET_CRYPTO_rsa_private_key_get_public (
+          denom_priv->details.rsa_private_key);
+    return;
+  // TODO: add case for Clause-Schnorr
+  default:
+    GNUNET_assert (0);
+  }
+}
+
+
+enum GNUNET_GenericReturnValue
+TALER_denom_pub_verify (const struct TALER_DenominationPublicKey *denom_pub,
+                        const struct TALER_DenominationSignature *denom_sig,
+                        const struct TALER_CoinPubHash *c_hash)
+{
+  if (denom_pub->cipher != denom_sig->cipher)
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  switch (denom_pub->cipher)
+  {
+  case TALER_DENOMINATION_RSA:
+    if (GNUNET_OK !=
+        GNUNET_CRYPTO_rsa_verify (&c_hash->hash,
+                                  denom_sig->details.rsa_signature,
+                                  denom_pub->details.rsa_public_key))
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                  "Coin signature is invalid\n");
+      return GNUNET_NO;
+    }
+    return GNUNET_YES;
+  // TODO: add case for Clause-Schnorr
+  default:
+    GNUNET_assert (0);
+  }
+}
+
+
+/* end of denom.c */