fixing #5178

5 files changed, 260 insertions, 358 deletions

diff --git a/src/include/taler_crypto_lib.h b/src/include/taler_crypto_lib.h
index d5024e6c8..d45e7bb28 100644
--- a/src/include/taler_crypto_lib.h
+++ b/src/include/taler_crypto_lib.h
@@ -1,6 +1,6 @@
 /*
   This file is part of TALER
-  Copyright (C) 2014, 2015 GNUnet e.V.
+  Copyright (C) 2014, 2015, 2016, 2017 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
@@ -289,6 +289,19 @@ struct TALER_DenominationBlindingKeyP
 };
 
 
+/**
+ * Commitment value for the refresh protocol.
+ * See #TALER_refresh_get_commitment().
+ */
+struct TALER_RefreshCommitmentP
+{
+  /**
+   * The commitment is a hash code.
+   */
+  struct GNUNET_HashCode session_hash;
+};
+
+
 GNUNET_NETWORK_STRUCT_END
 
 
@@ -557,12 +570,12 @@ GNUNET_NETWORK_STRUCT_END
  *
  * @param secret_seed seed to use for KDF to derive coin keys
  * @param coin_num_salt number of the coin to include in KDF
- * @param[out] fc value to initialize
+ * @param[out] ps value to initialize
  */
 void
 TALER_planchet_setup_refresh (const struct TALER_TransferSecretP *secret_seed,
-                              unsigned int coin_num_salt,
-                              struct TALER_PlanchetSecretsP *fc);
+                              uint32_t coin_num_salt,
+                              struct TALER_PlanchetSecretsP *ps);
 
 
 /**
@@ -656,4 +669,65 @@ TALER_link_recover_transfer_secret (const struct TALER_TransferPublicKeyP *trans
                                     struct TALER_TransferSecretP *transfer_secret);
 
 
+/**
+ * Information about a coin to be created during a refresh operation.
+ */
+struct TALER_RefreshCoinData
+{
+
+  /**
+   * The denomination's public key.
+   */
+  const struct TALER_DenominationPublicKey *dk;
+
+  /**
+   * The envelope with the blinded coin.
+   */
+  char *coin_ev;
+
+  /**
+   * Number of bytes in @a coin_ev
+   */
+  size_t coin_ev_size;
+
+};
+
+
+/**
+ * One of the #TALER_CNC_KAPPA commitments.
+ */
+struct TALER_RefreshCommitmentEntry
+{
+  /**
+   * Transfer public key of this commitment.
+   */
+  struct TALER_TransferPublicKeyP transfer_pub;
+
+  /**
+   * Array of @e num_new_coins new coins to be created.
+   */
+  struct TALER_RefreshCoinData *new_coins;
+};
+
+
+/**
+ * Compute the commitment for a /refresh/melt operation from
+ * the respective public inputs.
+ *
+ * @param[out] rc set to the value the wallet must commit to
+ * @param kappa number of transfer public keys involved (must be #TALER_CNC_KAPPA)
+ * @param num_new_coins number of new coins to be created
+ * @param commitments array of @a kappa commitments
+ * @param coin_pub public key of the coin to be melted
+ * @param amount_with_fee amount to be melted, including fee
+ */
+void
+TALER_refresh_get_commitment (struct TALER_RefreshCommitmentP *rc,
+                              uint32_t kappa,
+                              uint32_t num_new_coins,
+                              const struct TALER_RefreshCommitmentEntry *rcs,
+                              const struct TALER_CoinSpendPublicKeyP *coin_pub,
+                              const struct TALER_Amount *amount_with_fee);
+
+
 #endif
diff --git a/src/include/taler_error_codes.h b/src/include/taler_error_codes.h
index acc7228b1..6047e1643 100644
--- a/src/include/taler_error_codes.h
+++ b/src/include/taler_error_codes.h
@@ -68,6 +68,11 @@ enum TALER_ErrorCode
    */
   TALER_EC_TIMEOUT = 6,
 
+  /**
+   * Exchange failed to allocate memory for building JSON reply.
+   */
+  TALER_EC_JSON_ALLOCATION_FAILURE = 7,
+
   /* ********** generic error codes ************* */
 
   /**
@@ -428,6 +433,7 @@ enum TALER_ErrorCode
    */
   TALER_EC_DEPOSIT_INVALID_TIMESTAMP = 1218,
 
+
   /**
    * The respective coin did not have sufficient residual value
    * for the /refresh/melt operation.  The "history" in this
@@ -469,85 +475,25 @@ enum TALER_ErrorCode
   TALER_EC_REFRESH_MELT_DB_STORE_SESSION_ERROR = 1304,
 
   /**
-   * The exchange failed to store commit data in the
-   * database.
-   * This response is provided with HTTP status code
-   * MHD_HTTP_INTERNAL_ERROR.
-   */
-  TALER_EC_REFRESH_MELT_DB_STORE_COMMIT_ERROR = 1306,
-
-  /**
-   * The exchange is unaware of the denomination key that was
-   * requested for one of the fresh coins.  This response is provided
-   * with HTTP status code MHD_HTTP_BAD_REQUEST.
-   */
-  TALER_EC_REFRESH_MELT_FRESH_DENOMINATION_KEY_NOT_FOUND = 1308,
-
-  /**
-   * The exchange encountered a numeric overflow totaling up
-   * the cost for the refresh operation.  This response is provided
-   * with HTTP status code MHD_HTTP_INTERNAL_SERVER_ERROR.
-   */
-  TALER_EC_REFRESH_MELT_COST_CALCULATION_OVERFLOW = 1309,
-
-  /**
-   * During the transaction phase, the exchange could suddenly
-   * no longer find the denomination key that was
-   * used to sign the melted coin.  This response is provided
-   * with HTTP status code MHD_HTTP_INTERNAL_SERVER_ERROR.
-   */
-  TALER_EC_REFRESH_MELT_DB_DENOMINATION_KEY_NOT_FOUND = 1310,
-
-  /**
    * The exchange encountered melt fees exceeding the melted
    * coin's contribution.  This response is provided
    * with HTTP status code MHD_HTTP_BAD_REQUEST.
    */
-  TALER_EC_REFRESH_MELT_FEES_EXCEED_CONTRIBUTION = 1311,
-
-  /**
-   * The exchange's cost calculation does not add up to the
-   * melt fees specified in the request.  This response is provided
-   * with HTTP status code MHD_HTTP_BAD_REQUEST.
-   */
-  TALER_EC_REFRESH_MELT_FEES_MISSMATCH = 1312,
+  TALER_EC_REFRESH_MELT_FEES_EXCEED_CONTRIBUTION = 1305,
 
   /**
    * The denomination key signature on the melted coin is invalid.
    * This response is provided with HTTP status code
    * MHD_HTTP_BAD_REQUEST.
    */
-  TALER_EC_REFRESH_MELT_DENOMINATION_SIGNATURE_INVALID = 1313,
-
-  /**
-   * The exchange's cost calculation shows that the melt amount
-   * is below the costs of the transaction.  This response is provided
-   * with HTTP status code MHD_HTTP_BAD_REQUEST.
-   */
-  TALER_EC_REFRESH_MELT_AMOUNT_INSUFFICIENT = 1314,
+  TALER_EC_REFRESH_MELT_DENOMINATION_SIGNATURE_INVALID = 1306,
 
   /**
    * The signature made with the coin to be melted is invalid.
    * This response is provided with HTTP status code
    * MHD_HTTP_BAD_REQUEST.
    */
-  TALER_EC_REFRESH_MELT_COIN_SIGNATURE_INVALID = 1315,
-
-  /**
-   * The size of the cut-and-choose dimension of the
-   * blinded coins request does not match #TALER_CNC_KAPPA.
-   * This response is provided with HTTP status code
-   * MHD_HTTP_BAD_REQUEST.
-   */
-  TALER_EC_REFRESH_MELT_CNC_COIN_ARRAY_SIZE_INVALID = 1316,
-
-  /**
-   * The size of the cut-and-choose dimension of the
-   * transfer keys request does not match #TALER_CNC_KAPPA.
-   * This response is provided with HTTP status code
-   * MHD_HTTP_BAD_REQUEST.
-   */
-  TALER_EC_REFRESH_MELT_CNC_TRANSFER_ARRAY_SIZE_INVALID = 1317,
+  TALER_EC_REFRESH_MELT_COIN_SIGNATURE_INVALID = 1307,
 
   /**
    * The exchange failed to obtain the transaction history of the
@@ -556,7 +502,8 @@ enum TALER_ErrorCode
    * This response is provided with HTTP status code
    * MHD_HTTP_INTERNAL_SERVER_ERROR.
    */
-  TALER_EC_REFRESH_MELT_HISTORY_DB_ERROR_INSUFFICIENT_FUNDS = 1318,
+  TALER_EC_REFRESH_MELT_HISTORY_DB_ERROR_INSUFFICIENT_FUNDS = 1308,
+
 
   /**
    * The provided transfer keys do not match up with the
@@ -567,20 +514,12 @@ enum TALER_ErrorCode
   TALER_EC_REFRESH_REVEAL_COMMITMENT_VIOLATION = 1350,
 
   /**
-   * Failed to blind the envelope to reconstruct the blinded
-   * coins for revealation checks.
-   * This response is provided with HTTP status code
-   * MHD_HTTP_INTERNAL_ERROR.
-   */
-  TALER_EC_REFRESH_REVEAL_BLINDING_ERROR = 1351,
-
-  /**
    * Failed to produce the blinded signatures over the coins
    * to be returned.
    * This response is provided with HTTP status code
    * MHD_HTTP_INTERNAL_ERROR.
    */
-  TALER_EC_REFRESH_REVEAL_SIGNING_ERROR = 1352,
+  TALER_EC_REFRESH_REVEAL_SIGNING_ERROR = 1351,
 
   /**
    * The exchange is unaware of the refresh sessino specified in
@@ -588,7 +527,7 @@ enum TALER_ErrorCode
    * This response is provided with HTTP status code
    * MHD_HTTP_BAD_REQUEST.
    */
-  TALER_EC_REFRESH_REVEAL_SESSION_UNKNOWN = 1353,
+  TALER_EC_REFRESH_REVEAL_SESSION_UNKNOWN = 1352,
 
   /**
    * The exchange failed to retrieve valid session data from the
@@ -596,39 +535,68 @@ enum TALER_ErrorCode
    * This response is provided with HTTP status code
    * MHD_HTTP_INTERNAL_ERROR.
    */
-  TALER_EC_REFRESH_REVEAL_DB_FETCH_SESSION_ERROR = 1354,
+  TALER_EC_REFRESH_REVEAL_DB_FETCH_SESSION_ERROR = 1353,
 
   /**
-   * The exchange failed to retrieve order data from the
-   * database.
-   * This response is provided with HTTP status code
+   * The exchange failed to retrieve previously revealed data from the
+   * database.  This response is provided with HTTP status code
    * MHD_HTTP_INTERNAL_ERROR.
    */
-  TALER_EC_REFRESH_REVEAL_DB_FETCH_ORDER_ERROR = 1355,
+  TALER_EC_REFRESH_REVEAL_DB_FETCH_REVEAL_ERROR = 1354,
 
   /**
-   * The exchange failed to retrieve transfer keys from the
+   * The exchange failed to retrieve commitment data from the
    * database.
    * This response is provided with HTTP status code
    * MHD_HTTP_INTERNAL_ERROR.
    */
-  TALER_EC_REFRESH_REVEAL_DB_FETCH_TRANSFER_ERROR = 1356,
+  TALER_EC_REFRESH_REVEAL_DB_COMMIT_ERROR = 1355,
 
   /**
-   * The exchange failed to retrieve commitment data from the
-   * database.
+   * The size of the cut-and-choose dimension of the
+   * private transfer keys request does not match #TALER_CNC_KAPPA - 1.
    * This response is provided with HTTP status code
-   * MHD_HTTP_INTERNAL_ERROR.
+   * MHD_HTTP_BAD_REQUEST.
    */
-  TALER_EC_REFRESH_REVEAL_DB_FETCH_COMMIT_ERROR = 1357,
+  TALER_EC_REFRESH_REVEAL_CNC_TRANSFER_ARRAY_SIZE_INVALID = 1356,
 
   /**
-   * The size of the cut-and-choose dimension of the
+   * The number of coins to be created in refresh exceeds the limits
+   * of the exchange.
    * private transfer keys request does not match #TALER_CNC_KAPPA - 1.
    * This response is provided with HTTP status code
    * MHD_HTTP_BAD_REQUEST.
    */
-  TALER_EC_REFRESH_REVEAL_CNC_TRANSFER_ARRAY_SIZE_INVALID = 1358,
+  TALER_EC_REFRESH_REVEAL_NEW_DENOMS_ARRAY_SIZE_EXCESSIVE = 1357,
+
+  /**
+   * The number of envelopes given does not match the number
+   * of denomination keys given.
+   * This response is provided with HTTP status code
+   * MHD_HTTP_BAD_REQUEST.
+   */
+  TALER_EC_REFRESH_REVEAL_NEW_DENOMS_ARRAY_SIZE_MISSMATCH = 1358,
+
+  /**
+   * The exchange encountered a numeric overflow totaling up
+   * the cost for the refresh operation.  This response is provided
+   * with HTTP status code MHD_HTTP_INTERNAL_SERVER_ERROR.
+   */
+  TALER_EC_REFRESH_REVEAL_COST_CALCULATION_OVERFLOW = 1359,
+
+  /**
+   * The exchange's cost calculation shows that the melt amount
+   * is below the costs of the transaction.  This response is provided
+   * with HTTP status code MHD_HTTP_BAD_REQUEST.
+   */
+  TALER_EC_REFRESH_REVEAL_AMOUNT_INSUFFICIENT = 1360,
+
+  /**
+   * The exchange is unaware of the denomination key that was
+   * requested for one of the fresh coins.  This response is provided
+   * with HTTP status code MHD_HTTP_BAD_REQUEST.
+   */
+  TALER_EC_REFRESH_REVEAL_FRESH_DENOMINATION_KEY_NOT_FOUND = 1361,
 
 
   /**
diff --git a/src/include/taler_exchange_service.h b/src/include/taler_exchange_service.h
index fadcbf8b2..7e9ad914d 100644
--- a/src/include/taler_exchange_service.h
+++ b/src/include/taler_exchange_service.h
@@ -1,6 +1,6 @@
 /*
   This file is part of TALER
-  Copyright (C) 2014-2017 GNUnet e.V.
+  Copyright (C) 2014-2017 Taler Systems SA
 
   TALER 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
@@ -1110,7 +1110,7 @@ struct TALER_EXCHANGE_RefreshMeltHandle;
  *                    0 if the exchange's reply is bogus (fails to follow the protocol)
  * @param ec taler-specific error code, #TALER_EC_NONE on success
  * @param noreveal_index choice by the exchange in the cut-and-choose protocol,
- *                    UINT16_MAX on error
+ *                    UINT32_MAX on error
  * @param sign_key exchange key used to sign @a full_response, or NULL
  * @param full_response full response from the exchange (for logging, in case of errors)
  */
@@ -1118,7 +1118,7 @@ typedef void
 (*TALER_EXCHANGE_RefreshMeltCallback) (void *cls,
                                        unsigned int http_status,
 				       enum TALER_ErrorCode ec,
-				       uint16_t noreveal_index,
+				       uint32_t noreveal_index,
                                        const struct TALER_ExchangePublicKeyP *sign_key,
                                        const json_t *full_response);
 
@@ -1223,7 +1223,7 @@ struct TALER_EXCHANGE_RefreshRevealHandle *
 TALER_EXCHANGE_refresh_reveal (struct TALER_EXCHANGE_Handle *exchange,
                                size_t refresh_data_length,
                                const char *refresh_data,
-                               uint16_t noreveal_index,
+                               uint32_t noreveal_index,
                                TALER_EXCHANGE_RefreshRevealCallback reveal_cb,
                                void *reveal_cb_cls);
 
diff --git a/src/include/taler_exchangedb_plugin.h b/src/include/taler_exchangedb_plugin.h
index 006ea3981..e64b0ad4c 100644
--- a/src/include/taler_exchangedb_plugin.h
+++ b/src/include/taler_exchangedb_plugin.h
@@ -1,6 +1,6 @@
 /*
   This file is part of TALER
-  Copyright (C) 2014-2017 GNUnet e.V.
+  Copyright (C) 2014-2017 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
@@ -465,7 +465,7 @@ struct TALER_EXCHANGEDB_Refund
 /**
  * @brief Specification for coin in a /refresh/melt operation.
  */
-struct TALER_EXCHANGEDB_RefreshMelt
+struct TALER_EXCHANGEDB_RefreshSession
 {
   /**
    * Information about the coin that is being melted.
@@ -478,9 +478,9 @@ struct TALER_EXCHANGEDB_RefreshMelt
   struct TALER_CoinSpendSignatureP coin_sig;
 
   /**
-   * Hash of the refresh session this coin is melted into.
+   * Refresh commitment this coin is melted into.
    */
-  struct GNUNET_HashCode session_hash;
+  struct TALER_RefreshCommitmentP rc;
 
   /**
    * How much value is being melted?  This amount includes the fees,
@@ -493,64 +493,29 @@ struct TALER_EXCHANGEDB_RefreshMelt
   struct TALER_Amount amount_with_fee;
 
   /**
-   * Melting fee charged by the exchange.  This must match the Exchange's
-   * denomination key's melting fee.  If the client puts in an invalid
-   * melting fee (too high or too low) that does not match the Exchange's
-   * denomination key, the melting operation is invalid and will be
-   * rejected by the exchange.  The @e amount_with_fee minus the @e
-   * melt_fee is the amount that will be credited to the melting
-   * session.
-   */
-  struct TALER_Amount melt_fee;
-
-};
-
-
-/**
- * @brief Global information for a refreshing session.  Includes
- * dimensions of the operation, security parameters and
- * client signatures from "/refresh/melt" and "/refresh/commit".
- */
-struct TALER_EXCHANGEDB_RefreshSession
-{
-
-  /**
-   * Melt operation details.
-   */
-  struct TALER_EXCHANGEDB_RefreshMelt melt;
-
-  /**
-   * Number of new coins we are creating.
-   */
-  uint16_t num_newcoins;
-
-  /**
    * Index (smaller #TALER_CNC_KAPPA) which the exchange has chosen to not
    * have revealed during cut and choose.
    */
-  uint16_t noreveal_index;
+  uint32_t noreveal_index;
 
 };
 
 
 /**
- * @brief We have as many `struct TALER_EXCHANGEDB_RefreshCommitCoin` as there are new
- * coins being created by the refresh (for each of the #TALER_CNC_KAPPA
- * sets).  These are the coins we ask the exchange to sign if the
- * respective set is selected.
+ * Information about a /refresh/melt operation in the transaction history.
  */
-struct TALER_EXCHANGEDB_RefreshCommitCoin
+struct TALER_EXCHANGEDB_RefreshMelt
 {
 
   /**
-   * Blinded message to be signed (in envelope), with @e coin_env_size bytes.
+   * Overall session data.
    */
-  char *coin_ev;
+  struct TALER_EXCHANGEDB_RefreshSession session;
 
   /**
-   * Number of bytes in @e coin_ev.
+   * Melt fee the exchange charged.
    */
-  size_t coin_ev_size;
+  struct TALER_Amount melt_fee;
 
 };
 
@@ -752,9 +717,8 @@ typedef int
  * @param coin_pub public key of the coin
  * @param coin_sig signature from the coin
  * @param amount_with_fee amount that was deposited including fee
- * @param num_newcoins how many coins were issued
  * @param noreveal_index which index was picked by the exchange in cut-and-choose
- * @param session_hash what is the session hash
+ * @param rc what is the commitment
  * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
  */
 typedef int
@@ -764,9 +728,56 @@ typedef int
                                            const struct TALER_CoinSpendPublicKeyP *coin_pub,
                                            const struct TALER_CoinSpendSignatureP *coin_sig,
                                            const struct TALER_Amount *amount_with_fee,
-                                           uint16_t num_newcoins,
-                                           uint16_t noreveal_index,
-                                           const struct GNUNET_HashCode *session_hash);
+                                           uint32_t noreveal_index,
+                                           const struct TALER_RefreshCommitmentP *rc);
+
+
+/**
+ * Information about a coin that was revealed to the exchange
+ * during /refresh/reveal.
+ */
+struct TALER_EXCHANGEDB_RefreshRevealedCoin
+{
+  /**
+   * Public denomination key of the coin.
+   */
+  struct TALER_DenominationPublicKey denom_pub;
+
+  /**
+   * Blinded message to be signed (in envelope), with @e coin_env_size bytes.
+   */
+  char *coin_ev;
+
+  /**
+   * Number of bytes in @e coin_ev.
+   */
+  size_t coin_ev_size;
+
+  /**
+   * Signature generated by the exchange over the coin (in blinded format).
+   */
+  struct TALER_DenominationSignature coin_sig;
+};
+
+
+/**
+ * Function called with information about a refresh order.
+ *
+ * @param cls closure
+ * @param rowid unique serial ID for the row in our database
+ * @param num_newcoins size of the @a rrcs array
+ * @param rrcs array of @a num_newcoins information about coins to be created
+ * @param num_tprivs number of entries in @a tprivs, should be #TALER_CNC_KAPPA - 1
+ * @param tprivs array of @e num_tprivs transfer private keys
+ * @param tp transfer public key information
+ */
+typedef void
+(*TALER_EXCHANGEDB_RefreshCallback)(void *cls,
+                                    uint32_t num_newcoins,
+                                    const struct TALER_EXCHANGEDB_RefreshRevealedCoin *rrcs,
+                                    unsigned int num_tprivs,
+                                    const struct TALER_TransferPrivateKeyP *tprivs,
+                                    const struct TALER_TransferPublicKeyP *tp);
 
 
 /**
@@ -851,14 +862,13 @@ typedef int
  * information for a given coin.
  *
  * @param cls closure
- * @param session_hash a session the coin was melted in
  * @param transfer_pub public transfer key for the session
- * @param shared_secret_enc set to shared secret for the session
+ * @param ldl link data for @a transfer_pub
  */
 typedef void
-(*TALER_EXCHANGEDB_TransferDataCallback)(void *cls,
-                                         const struct GNUNET_HashCode *session_hash,
-                                         const struct TALER_TransferPublicKeyP *transfer_pub);
+(*TALER_EXCHANGEDB_LinkDataCallback)(void *cls,
+                                     const struct TALER_TransferPublicKeyP *transfer_pub,
+                                     const struct TALER_EXCHANGEDB_LinkDataList *ldl);
 
 
 /**
@@ -1235,7 +1245,7 @@ struct TALER_EXCHANGEDB_Plugin
    * @param[out] wire_reference_size set to number of bytes in @a wire_reference
    * @return transaction status code
    */
-  enum GNUNET_DB_QueryStatus 
+  enum GNUNET_DB_QueryStatus
   (*get_latest_reserve_in_reference)(void *cls,
                                      struct TALER_EXCHANGEDB_Session *db,
                                      void **wire_reference,
@@ -1254,7 +1264,7 @@ struct TALER_EXCHANGEDB_Plugin
    *                    if a coin is found
    * @return statement execution status
    */
-  enum GNUNET_DB_QueryStatus 
+  enum GNUNET_DB_QueryStatus
   (*get_withdraw_info) (void *cls,
                         struct TALER_EXCHANGEDB_Session *session,
                         const struct GNUNET_HashCode *h_blind,
@@ -1454,225 +1464,79 @@ struct TALER_EXCHANGEDB_Plugin
 
 
   /**
-   * Lookup refresh session data under the given @a session_hash.
+   * Store new refresh melt commitment data.
    *
    * @param cls the @e cls of this struct with the plugin-specific state
    * @param session database handle to use
-   * @param session_hash hash over the melt to use for the lookup
-   * @param[out] refresh_session where to store the result
-   * @return transaction status
-   */
-  enum GNUNET_DB_QueryStatus
-  (*get_refresh_session) (void *cls,
-                          struct TALER_EXCHANGEDB_Session *session,
-                          const struct GNUNET_HashCode *session_hash,
-                          struct TALER_EXCHANGEDB_RefreshSession *refresh_session);
-
-
-  /**
-   * Store new refresh session data under the given @a session_hash.
-   *
-   * @param cls the @e cls of this struct with the plugin-specific state
-   * @param session database handle to use
-   * @param session_hash hash over the melt to use to locate the session
-   * @param refresh_session session data to store
-   * @return query status for the transaction
-   */
-  enum GNUNET_DB_QueryStatus
-  (*create_refresh_session) (void *cls,
-                             struct TALER_EXCHANGEDB_Session *session,
-                             const struct GNUNET_HashCode *session_hash,
-                             const struct TALER_EXCHANGEDB_RefreshSession *refresh_session);
-
-
-  /**
-   * Store in the database which coin(s) we want to create
-   * in a given refresh operation.
-   *
-   * @param cls the @e cls of this struct with the plugin-specific state
-   * @param session database connection
-   * @param session_hash hash to identify refresh session
-   * @param num_newcoins number of coins to generate, size of the @a denom_pubs array
-   * @param denom_pubs array denominations of the coins to create
-   * @return query status for the transaction
-   */
-  enum GNUNET_DB_QueryStatus
-  (*insert_refresh_order) (void *cls,
-                           struct TALER_EXCHANGEDB_Session *session,
-                           const struct GNUNET_HashCode *session_hash,
-                           uint16_t num_newcoins,
-                           const struct TALER_DenominationPublicKey *denom_pubs);
-
-
-  /**
-   * Lookup in the database for the @a num_newcoins coins that we want to
-   * create in the given refresh operation.
-   *
-   * @param cls the @e cls of this struct with the plugin-specific state
-   * @param session database connection
-   * @param session_hash hash to identify refresh session
-   * @param num_newcoins size of the @a denom_pubs array
-   * @param[out] denom_pubs where to write @a num_newcoins denomination keys
-   * @return transaction status
-   */
-  enum GNUNET_DB_QueryStatus
-  (*get_refresh_order) (void *cls,
-                        struct TALER_EXCHANGEDB_Session *session,
-                        const struct GNUNET_HashCode *session_hash,
-                        uint16_t num_newcoins,
-                        struct TALER_DenominationPublicKey *denom_pubs);
-
-
-  /**
-   * Store information about the commitments of the given index @a i
-   * for the given refresh session in the database.
-   *
-   * @param cls the @e cls of this struct with the plugin-specific state
-   * @param session database connection to use
-   * @param session_hash hash to identify refresh session
-   * @param num_newcoins coin index size of the @a commit_coins array
-   * @param commit_coin array of coin commitments to store
+   * @param refresh_session operational data to store
    * @return query status for the transaction
    */
   enum GNUNET_DB_QueryStatus
-  (*insert_refresh_commit_coins) (void *cls,
-                                  struct TALER_EXCHANGEDB_Session *session,
-                                  const struct GNUNET_HashCode *session_hash,
-                                  uint16_t num_newcoins,
-                                  const struct TALER_EXCHANGEDB_RefreshCommitCoin *commit_coins);
+  (*insert_melt) (void *cls,
+                  struct TALER_EXCHANGEDB_Session *session,
+                  const struct TALER_EXCHANGEDB_RefreshSession *refresh_session);
 
 
   /**
-   * Obtain information about the commitment of the
-   * given coin of the given refresh session from the database.
+   * Lookup refresh metl commitment data under the given @a rc.
    *
    * @param cls the @e cls of this struct with the plugin-specific state
-   * @param session database connection to use
-   * @param session_hash hash to identify refresh session
-   * @param num_coins size of the @a commit_coins array
-   * @param[out] commit_coins array of coin commitments to return
+   * @param session database handle to use
+   * @param rc commitment to use for the lookup
+   * @param[out] refresh_melt where to store the result
    * @return transaction status
    */
   enum GNUNET_DB_QueryStatus
-  (*get_refresh_commit_coins) (void *cls,
-                               struct TALER_EXCHANGEDB_Session *session,
-                               const struct GNUNET_HashCode *session_hash,
-                               uint16_t num_coins,
-                               struct TALER_EXCHANGEDB_RefreshCommitCoin *commit_coins);
-
-  /**
-   * Free refresh @a commit_coins data obtained via @e get_refresh_commit_coins.
-   *
-   * @param cls the @e cls of this struct with the plugin-specific state
-   * @param num_coins size of the @a commit_coins array
-   * @param commit_coins array of coin commitments to free
-   */
-  void
-  (*free_refresh_commit_coins) (void *cls,
-                                unsigned int num_coins,
-                                struct TALER_EXCHANGEDB_RefreshCommitCoin *commit_coins);
+  (*get_melt) (void *cls,
+               struct TALER_EXCHANGEDB_Session *session,
+               const struct TALER_RefreshCommitmentP *rc,
+               struct TALER_EXCHANGEDB_RefreshMelt *refresh_melt);
 
 
   /**
-   * Store the commitment to the given (encrypted) refresh link data
-   * for the given refresh session.
+   * Store in the database which coin(s) the wallet wanted to create
+   * in a given refresh operation and all of the other information
+   * we learned or created in the /refresh/reveal step.
    *
    * @param cls the @e cls of this struct with the plugin-specific state
-   * @param session database connection to use
-   * @param session_hash hash to identify refresh session
+   * @param session database connection
+   * @param rc identify commitment and thus refresh operation
+   * @param num_rrcs_newcoins number of coins to generate, size of the
+   *            @a rrcs array
+   * @param rrcs information about the new coins
+   * @param num_tprivs number of entries in @a tprivs, should be #TALER_CNC_KAPPA - 1
+   * @param tprivs transfer private keys to store
    * @param tp public key to store
    * @return query status for the transaction
    */
   enum GNUNET_DB_QueryStatus
-  (*insert_refresh_transfer_public_key) (void *cls,
-                                         struct TALER_EXCHANGEDB_Session *session,
-                                         const struct GNUNET_HashCode *session_hash,
-                                         const struct TALER_TransferPublicKeyP *tp);
-
-  /**
-   * Obtain the commited (encrypted) refresh link data
-   * for the given refresh session.
-   *
-   * @param cls the @e cls of this struct with the plugin-specific state
-   * @param session database connection to use
-   * @param session_hash hash to identify refresh session
-   * @param[out] tp information to return
-   * @return transaction status
-   */
-  enum GNUNET_DB_QueryStatus
-  (*get_refresh_transfer_public_key) (void *cls,
-                                      struct TALER_EXCHANGEDB_Session *session,
-                                      const struct GNUNET_HashCode *session_hash,
-                                      struct TALER_TransferPublicKeyP *tp);
-
-
-  /**
-   * Get signature of a new coin generated during refresh into
-   * the database indexed by the refresh session and the index
-   * of the coin.
-   *
-   * @param cls the @e cls of this struct with the plugin-specific state
-   * @param session database connection
-   * @param session_hash hash to identify refresh session
-   * @param newcoin_index coin index
-   * @param[out] ev_sig coin signature
-   * @return transaction result status
-   */
-  enum GNUNET_DB_QueryStatus
-  (*get_refresh_out) (void *cls,
-                      struct TALER_EXCHANGEDB_Session *session,
-                      const struct GNUNET_HashCode *session_hash,
-                      uint16_t newcoin_index,
-                      struct TALER_DenominationSignature *ev_sig);
-
-
-  /**
-   * Insert signature of a new coin generated during refresh into
-   * the database indexed by the refresh session and the index
-   * of the coin.  This data is later used should an old coin
-   * be used to try to obtain the private keys during "/refresh/link".
-   *
-   * @param cls the @e cls of this struct with the plugin-specific state
-   * @param session database connection
-   * @param session_hash hash to identify refresh session
-   * @param newcoin_index coin index
-   * @param ev_sig coin signature
-   * @return transaction result status
-   */
-  enum GNUNET_DB_QueryStatus
-  (*insert_refresh_out) (void *cls,
-                         struct TALER_EXCHANGEDB_Session *session,
-                         const struct GNUNET_HashCode *session_hash,
-                         uint16_t newcoin_index,
-                         const struct TALER_DenominationSignature *ev_sig);
+  (*insert_refresh_reveal) (void *cls,
+                            struct TALER_EXCHANGEDB_Session *session,
+                            const struct TALER_RefreshCommitmentP *rc,
+                            uint32_t num_rrcs,
+                            const struct TALER_EXCHANGEDB_RefreshRevealedCoin *rrcs,
+                            unsigned int num_tprivs,
+                            const struct TALER_TransferPrivateKeyP *tprivs,
+                            const struct TALER_TransferPublicKeyP *tp);
 
 
   /**
-   * Obtain the link data of a coin, that is the encrypted link
-   * information, the denomination keys and the signatures.
+   * Lookup in the database for the @a num_newcoins coins that we
+   * created in the given refresh operation.
    *
    * @param cls the @e cls of this struct with the plugin-specific state
    * @param session database connection
-   * @param session_hash session to get linkage data for
-   * @param[out] ldldp set to all known link data for the session
-   * @return status of the transaction
+   * @param rc identify commitment and thus refresh operation
+   * @param cb function to call with the results
+   * @param cb_cls closure for @a cb
+   * @return transaction status
    */
   enum GNUNET_DB_QueryStatus
-  (*get_link_data_list) (void *cls,
+  (*get_refresh_reveal) (void *cls,
                          struct TALER_EXCHANGEDB_Session *session,
-                         const struct GNUNET_HashCode *session_hash,
-			 struct TALER_EXCHANGEDB_LinkDataList **ldlp);
-
-
-  /**
-   * Free memory of the link data list.
-   *
-   * @param cls the @e cls of this struct with the plugin-specific state
-   * @param ldl link data list to release
-   */
-  void
-  (*free_link_data_list) (void *cls,
-                          struct TALER_EXCHANGEDB_LinkDataList *ldl);
+                         const struct TALER_RefreshCommitmentP *rc,
+                         TALER_EXCHANGEDB_RefreshCallback cb,
+                         void *cb_cls);
 
 
   /**
@@ -1684,16 +1548,16 @@ struct TALER_EXCHANGEDB_Plugin
    * @param cls the @e cls of this struct with the plugin-specific state
    * @param session database connection
    * @param coin_pub public key of the coin
-   * @param tdc function to call for each session the coin was melted into
-   * @param tdc_cls closure for @a tdc
+   * @param ldc function to call for each session the coin was melted into
+   * @param ldc_cls closure for @a tdc
    * @return statement execution status
    */
   enum GNUNET_DB_QueryStatus
-  (*get_transfer) (void *cls,
-                   struct TALER_EXCHANGEDB_Session *session,
-                   const struct TALER_CoinSpendPublicKeyP *coin_pub,
-                   TALER_EXCHANGEDB_TransferDataCallback tdc,
-                   void *tdc_cls);
+  (*get_link_data) (void *cls,
+                    struct TALER_EXCHANGEDB_Session *session,
+                    const struct TALER_CoinSpendPublicKeyP *coin_pub,
+                    TALER_EXCHANGEDB_LinkDataCallback ldc,
+                    void *tdc_cls);
 
 
   /**
@@ -1806,7 +1670,7 @@ struct TALER_EXCHANGEDB_Plugin
                      const struct TALER_Amount *wire_fee,
                      const struct TALER_MasterSignatureP *master_sig);
 
-  
+
   /**
    * Obtain wire fee from database.
    *
@@ -2233,7 +2097,7 @@ struct TALER_EXCHANGEDB_Plugin
 				  struct GNUNET_TIME_Absolute end_date,
 				  TALER_EXCHANGEDB_WireMissingCallback cb,
 				  void *cb_cls);
-  
+
 
 };
 
diff --git a/src/include/taler_signatures.h b/src/include/taler_signatures.h
index db71cca68..3bc0505f9 100644
--- a/src/include/taler_signatures.h
+++ b/src/include/taler_signatures.h
@@ -532,9 +532,9 @@ struct TALER_RefreshMeltCoinAffirmationPS
   struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
 
   /**
-   * Which melting session should the coin become a part of.
+   * Which melt commitment is made by the wallet.
    */
-  struct GNUNET_HashCode session_hash GNUNET_PACKED;
+  struct TALER_RefreshCommitmentP rc GNUNET_PACKED;
 
   /**
    * How much of the value of the coin should be melted?  This amount
@@ -581,20 +581,16 @@ struct TALER_RefreshMeltConfirmationPS
   struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
 
   /**
-   * Hash of the refresh session.
+   * Commitment made in the /refresh/melt.
    */
-  struct GNUNET_HashCode session_hash GNUNET_PACKED;
+  struct TALER_RefreshCommitmentP rc GNUNET_PACKED;
 
   /**
    * Index that the client will not have to reveal, in NBO.
    * Must be smaller than #TALER_CNC_KAPPA.
    */
-  uint16_t noreveal_index GNUNET_PACKED;
+  uint32_t noreveal_index GNUNET_PACKED;
 
-  /**
-   * Zero.
-   */
-  uint16_t reserved GNUNET_PACKED;
 };