1 files changed, 80 insertions, 0 deletions
diff --git a/src/util/wallet_signatures.c b/src/util/wallet_signatures.c
new file mode 100644
index 00000000..ef343d17
--- /dev/null
+++ b/src/util/wallet_signatures.c
@@ -0,0 +1,80 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2020 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 secmod_signatures.c
+ * @brief Utility functions for Taler security module signatures
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "taler_util.h"
+#include "taler_signatures.h"
+
+
+void
+TALER_wallet_link_sign (const struct GNUNET_HashCode *h_denom_pub,
+                        const struct TALER_TransferPublicKeyP *transfer_pub,
+                        const void *coin_ev,
+                        size_t coin_ev_size,
+                        const struct TALER_CoinSpendPrivateKeyP *old_coin_priv,
+                        struct TALER_CoinSpendSignatureP *coin_sig)
+{
+  struct TALER_LinkDataPS ldp = {
+    .purpose.size = htonl (sizeof (ldp)),
+    .purpose.purpose = htonl (TALER_SIGNATURE_WALLET_COIN_LINK),
+    .h_denom_pub = *h_denom_pub,
+    .transfer_pub = *transfer_pub
+  };
+
+  GNUNET_CRYPTO_hash (coin_ev,
+                      coin_ev_size,
+                      &ldp.coin_envelope_hash);
+  GNUNET_CRYPTO_eddsa_key_get_public (&old_coin_priv->eddsa_priv,
+                                      &ldp.old_coin_pub.eddsa_pub);
+  GNUNET_CRYPTO_eddsa_sign (&old_coin_priv->eddsa_priv,
+                            &ldp,
+                            &coin_sig->eddsa_signature);
+}
+
+
+enum GNUNET_GenericReturnValue
+TALER_wallet_link_verify (
+  const struct GNUNET_HashCode *h_denom_pub,
+  const struct TALER_TransferPublicKeyP *transfer_pub,
+  const void *coin_ev,
+  size_t coin_ev_size,
+  const struct TALER_CoinSpendPublicKeyP *old_coin_pub,
+  const struct TALER_CoinSpendSignatureP *coin_sig)
+{
+  struct TALER_LinkDataPS ldp = {
+    .purpose.size = htonl (sizeof (ldp)),
+    .purpose.purpose = htonl (TALER_SIGNATURE_WALLET_COIN_LINK),
+    .h_denom_pub = *h_denom_pub,
+    .old_coin_pub = *old_coin_pub,
+    .transfer_pub = *transfer_pub
+  };
+
+  GNUNET_CRYPTO_hash (coin_ev,
+                      coin_ev_size,
+                      &ldp.coin_envelope_hash);
+  return
+    GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_WALLET_COIN_LINK,
+                                &ldp,
+                                &coin_sig->eddsa_signature,
+                                &old_coin_pub->eddsa_pub);
+}
+
+
+/* end of wallet_signatures.c */