3 files changed, 63 insertions, 4 deletions
diff --git a/src/include/taler_error_codes.h b/src/include/taler_error_codes.h
index fbd983520..5767a73b2 100644
--- a/src/include/taler_error_codes.h
+++ b/src/include/taler_error_codes.h
@@ -617,7 +617,14 @@ enum TALER_ErrorCode
    */
   TALER_EC_REFRESH_REVEAL_FRESH_DENOMINATION_KEY_NOT_FOUND = 1361,
 
+  /**
+   * The signature made with the coin over the link data is invalid.
+   * This response is provided with HTTP status code
+   * MHD_HTTP_BAD_REQUEST.
+   */
+  TALER_EC_REFRESH_REVEAL_LINK_SIGNATURE_INVALID = 1362,
 
+  
   /**
    * The coin specified in the link request is unknown to the exchange.
    * This response is provided with HTTP status code
diff --git a/src/include/taler_exchangedb_plugin.h b/src/include/taler_exchangedb_plugin.h
index 6f1625dd0..67ebc62fc 100644
--- a/src/include/taler_exchangedb_plugin.h
+++ b/src/include/taler_exchangedb_plugin.h
@@ -541,6 +541,12 @@ struct TALER_EXCHANGEDB_LinkDataList
    * Signature over the blinded envelope.
    */
   struct TALER_DenominationSignature ev_sig;
+
+  /**
+   * Signature of the original coin being refreshed over the
+   * link data, of type #TALER_SIGNATURE_WALLET_COIN_LINK
+   */
+  struct TALER_CoinSpendSignatureP orig_coin_link_sig;
 };
 
 
@@ -794,6 +800,12 @@ struct TALER_EXCHANGEDB_RefreshRevealedCoin
   struct TALER_DenominationPublicKey denom_pub;
 
   /**
+   * Signature of the original coin being refreshed over the
+   * link data, of type #TALER_SIGNATURE_WALLET_COIN_LINK
+   */
+  struct TALER_CoinSpendSignatureP orig_coin_link_sig;
+  
+  /**
    * Blinded message to be signed (in envelope), with @e coin_env_size bytes.
    */
   char *coin_ev;
@@ -1634,7 +1646,7 @@ struct TALER_EXCHANGEDB_Plugin
 
 
   /**
-   * Lookup refresh metl commitment data under the given @a rc.
+   * Lookup refresh melt commitment data under the given @a rc.
    *
    * @param cls the @e cls of this struct with the plugin-specific state
    * @param session database handle to use
diff --git a/src/include/taler_signatures.h b/src/include/taler_signatures.h
index bff73f737..b738e3156 100644
--- a/src/include/taler_signatures.h
+++ b/src/include/taler_signatures.h
@@ -130,9 +130,9 @@
 #define TALER_SIGNATURE_EXCHANGE_RESERVE_CLOSED 1040
 
 
-/*********************/
-/* Wallet signatures */
-/*********************/
+/**********************/
+/* Auditor signatures */
+/**********************/
 
 /**
  * Signature where the auditor confirms that he is
@@ -209,6 +209,11 @@
  */
 #define TALER_SIGNATURE_WALLET_COIN_PAYBACK 1203
 
+/**
+ * Signature using a coin key authenticating link data.
+ */
+#define TALER_SIGNATURE_WALLET_COIN_LINK 1204
+
 
 /*******************/
 /* Test signatures */
@@ -229,6 +234,41 @@
 GNUNET_NETWORK_STRUCT_BEGIN
 
 /**
+ * @brief Format used for to allow the wallet to authenticate
+ * link data provided by the exchange.
+ */
+struct TALER_LinkDataPS
+{
+
+  /**
+   * Purpose must be #TALER_SIGNATURE_WALLET_COIN_LINK.
+   * Used with an EdDSA signature of a `struct TALER_CoinPublicKeyP`.
+   */
+  struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
+
+  /**
+   * Hash of the denomination public key of the new coin.
+   */
+  struct GNUNET_HashCode h_denom_pub;
+
+  /**
+   * Public key of the old coin being refreshed.
+   */
+  struct TALER_CoinSpendPublicKeyP old_coin_pub;
+
+  /**
+   * Transfer public key (for which the private key was not revealed)
+   */
+  struct TALER_TransferPublicKeyP transfer_pub;
+
+  /**
+   * Hash of the blinded new coin.
+   */
+  struct GNUNET_HashCode coin_envelope_hash;
+};
+
+
+/**
  * @brief Format used for to generate the signature on a request to withdraw
  * coins from a reserve.
  */