-move econtract into sub-object with its own parser

7 files changed, 312 insertions, 211 deletions

diff --git a/src/exchange/taler-exchange-httpd_purses_create.c b/src/exchange/taler-exchange-httpd_purses_create.c
index b46d27958..65cd5d455 100644
--- a/src/exchange/taler-exchange-httpd_purses_create.c
+++ b/src/exchange/taler-exchange-httpd_purses_create.c
@@ -107,9 +107,9 @@ struct PurseCreateContext
   struct TALER_PurseMergePublicKeyP merge_pub;
 
   /**
-   * Contract decryption key for the purse.
+   * Encrypted contract of for the purse.
    */
-  struct TALER_ContractDiffiePublicP contract_pub;
+  struct TALER_EncryptedContract econtract;
 
   /**
    * Signature of the client affiming this request.
@@ -117,11 +117,6 @@ struct PurseCreateContext
   struct TALER_PurseContractSignatureP purse_sig;
 
   /**
-   * Signature of the client affiming this encrypted contract.
-   */
-  struct TALER_PurseContractSignatureP econtract_sig;
-
-  /**
    * Hash of the contract terms of the purse.
    */
   struct TALER_PrivateContractHashP h_contract_terms;
@@ -132,16 +127,6 @@ struct PurseCreateContext
   struct Coin *coins;
 
   /**
-   * Encrypted contract, can be NULL.
-   */
-  void *econtract;
-
-  /**
-   * Number of bytes in @e econtract.
-   */
-  size_t econtract_size;
-
-  /**
    * Length of the @e coins array.
    */
   unsigned int num_coins;
@@ -384,12 +369,13 @@ create_transaction (void *cls,
   }
   /* 3) if present, persist contract */
   in_conflict = true;
+  // FIXME: combine econtract arguments into one!
   qs = TEH_plugin->insert_contract (TEH_plugin->cls,
                                     pcc->purse_pub,
-                                    &pcc->contract_pub,
-                                    pcc->econtract_size,
-                                    pcc->econtract,
-                                    &pcc->econtract_sig,
+                                    &pcc->econtract.contract_pub,
+                                    pcc->econtract.econtract_size,
+                                    pcc->econtract.econtract,
+                                    &pcc->econtract.econtract_sig,
                                     &in_conflict);
   if (qs < 0)
   {
@@ -404,19 +390,17 @@ create_transaction (void *cls,
   }
   if (in_conflict)
   {
-    struct TALER_ContractDiffiePublicP pub_ckey;
-    struct TALER_PurseContractSignatureP econtract_sig;
-    size_t econtract_size;
-    void *econtract;
+    struct TALER_EncryptedContract econtract;
     struct GNUNET_HashCode h_econtract;
 
+    // FIXME: combine econtract arguments into one!
     qs = TEH_plugin->select_contract_by_purse (
       TEH_plugin->cls,
       pcc->purse_pub,
-      &pub_ckey,
-      &econtract_sig,
-      &econtract_size,
-      &econtract);
+      &econtract.contract_pub,
+      &econtract.econtract_sig,
+      &econtract.econtract_size,
+      &econtract.econtract);
     if (qs <= 0)
     {
       if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
@@ -430,8 +414,8 @@ create_transaction (void *cls,
                                              "select contract");
       return GNUNET_DB_STATUS_HARD_ERROR;
     }
-    GNUNET_CRYPTO_hash (econtract,
-                        econtract_size,
+    GNUNET_CRYPTO_hash (econtract.econtract,
+                        econtract.econtract_size,
                         &h_econtract);
     *mhd_ret
       = TALER_MHD_REPLY_JSON_PACK (
@@ -442,9 +426,10 @@ create_transaction (void *cls,
           GNUNET_JSON_pack_data_auto ("h_econtract",
                                       &h_econtract),
           GNUNET_JSON_pack_data_auto ("econtract_sig",
-                                      &econtract_sig),
+                                      &econtract.econtract_sig),
           GNUNET_JSON_pack_data_auto ("pub_ckey",
-                                      &pub_ckey));
+                                      &econtract.contract_pub));
+    GNUNET_free (econtract.econtract);
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   return qs;
@@ -685,6 +670,7 @@ TEH_handler_purses_create (
   json_t *deposits;
   json_t *deposit;
   unsigned int idx;
+  bool no_econtract = true;
   struct GNUNET_JSON_Specification spec[] = {
     TALER_JSON_spec_amount ("amount",
                             TEH_currency,
@@ -692,18 +678,9 @@ TEH_handler_purses_create (
     GNUNET_JSON_spec_uint32 ("min_age",
                              &pcc.min_age),
     GNUNET_JSON_spec_mark_optional (
-      GNUNET_JSON_spec_varsize ("econtract",
-                                &pcc.econtract,
-                                &pcc.econtract_size),
-      NULL),
-    GNUNET_JSON_spec_mark_optional (
-      GNUNET_JSON_spec_fixed_auto ("econtract_sig",
-                                   &pcc.econtract_sig),
-      NULL),
-    GNUNET_JSON_spec_mark_optional (
-      GNUNET_JSON_spec_fixed_auto ("contract_pub",
-                                   &pcc.contract_pub),
-      NULL),
+      TALER_JSON_spec_econtract ("econtract",
+                                 &pcc.econtract),
+      &no_econtract),
     GNUNET_JSON_spec_fixed_auto ("merge_pub",
                                  &pcc.merge_pub),
     GNUNET_JSON_spec_fixed_auto ("purse_sig",
@@ -830,13 +807,13 @@ TEH_handler_purses_create (
                                        TALER_EC_EXCHANGE_PURSE_CREATE_SIGNATURE_INVALID,
                                        NULL);
   }
-  if ( (NULL != pcc.econtract) &&
+  if ( (! no_econtract) &&
        (GNUNET_OK !=
-        TALER_wallet_econtract_upload_verify (pcc.econtract,
-                                              pcc.econtract_size,
-                                              &pcc.contract_pub,
+        TALER_wallet_econtract_upload_verify (pcc.econtract.econtract,
+                                              pcc.econtract.econtract_size,
+                                              &pcc.econtract.contract_pub,
                                               purse_pub,
-                                              &pcc.econtract_sig)) )
+                                              &pcc.econtract.econtract_sig)) )
   {
     TALER_LOG_WARNING ("Invalid signature on /purses/$PID/create request\n");
     GNUNET_JSON_parse_free (spec);
diff --git a/src/exchange/taler-exchange-httpd_reserves_purse.c b/src/exchange/taler-exchange-httpd_reserves_purse.c
index 44f3e85c3..af86bc91e 100644
--- a/src/exchange/taler-exchange-httpd_reserves_purse.c
+++ b/src/exchange/taler-exchange-httpd_reserves_purse.c
@@ -86,6 +86,11 @@ struct ReservePurseContext
   struct GNUNET_TIME_Timestamp exchange_timestamp;
 
   /**
+   * Details about an encrypted contract, if any.
+   */
+  struct TALER_EncryptedContract econtract;
+
+  /**
    * Merge key for the purse.
    */
   struct TALER_PurseMergePublicKeyP merge_pub;
@@ -96,11 +101,6 @@ struct ReservePurseContext
   struct TALER_PurseMergeSignatureP merge_sig;
 
   /**
-   * Contract decryption key for the purse.
-   */
-  struct TALER_ContractDiffiePublicP contract_pub;
-
-  /**
    * Public key of the purse we are creating.
    */
   struct TALER_PurseContractPublicKeyP purse_pub;
@@ -111,26 +111,11 @@ struct ReservePurseContext
   struct TALER_PurseContractSignatureP purse_sig;
 
   /**
-   * Signature of the client affiming this encrypted contract.
-   */
-  struct TALER_PurseContractSignatureP econtract_sig;
-
-  /**
    * Hash of the contract terms of the purse.
    */
   struct TALER_PrivateContractHashP h_contract_terms;
 
   /**
-   * Encrypted contract, can be NULL.
-   */
-  void *econtract;
-
-  /**
-   * Number of bytes in @e econtract.
-   */
-  size_t econtract_size;
-
-  /**
    * Minimum age for deposits into this purse.
    */
   uint32_t min_age;
@@ -139,6 +124,12 @@ struct ReservePurseContext
    * Flags for the operation.
    */
   enum TALER_WalletAccountMergeFlags flags;
+
+  /**
+   * Do we lack an @e econtract?
+   */
+  bool no_econtract;
+
 };
 
 
@@ -214,17 +205,18 @@ purse_transaction (void *cls,
     bool in_conflict = true;
 
     /* 1) store purse */
-    qs = TEH_plugin->insert_purse_request (TEH_plugin->cls,
-                                           &rpc->purse_pub,
-                                           &rpc->merge_pub,
-                                           rpc->purse_expiration,
-                                           &rpc->h_contract_terms,
-                                           rpc->min_age,
-                                           rpc->flags,
-                                           &rpc->purse_fee,
-                                           &rpc->amount,
-                                           &rpc->purse_sig,
-                                           &in_conflict);
+    qs = TEH_plugin->insert_purse_request (
+      TEH_plugin->cls,
+      &rpc->purse_pub,
+      &rpc->merge_pub,
+      rpc->purse_expiration,
+      &rpc->h_contract_terms,
+      rpc->min_age,
+      rpc->flags,
+      &rpc->purse_fee,
+      &rpc->amount,
+      &rpc->purse_sig,
+      &in_conflict);
     if (qs < 0)
     {
       if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
@@ -251,15 +243,16 @@ purse_transaction (void *cls,
       uint32_t min_age;
 
       TEH_plugin->rollback (TEH_plugin->cls);
-      qs = TEH_plugin->select_purse_request (TEH_plugin->cls,
-                                             &rpc->purse_pub,
-                                             &merge_pub,
-                                             &purse_expiration,
-                                             &h_contract_terms,
-                                             &min_age,
-                                             &target_amount,
-                                             &balance,
-                                             &purse_sig);
+      qs = TEH_plugin->select_purse_request (
+        TEH_plugin->cls,
+        &rpc->purse_pub,
+        &merge_pub,
+        &purse_expiration,
+        &h_contract_terms,
+        &min_age,
+        &target_amount,
+        &balance,
+        &purse_sig);
       if (qs <= 0)
       {
         GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR != qs);
@@ -414,16 +407,17 @@ purse_transaction (void *cls,
     }
   }
   /* 3) if present, persist contract */
-  if (NULL != rpc->econtract)
+  if (! rpc->no_econtract)
   {
     bool in_conflict = true;
 
+    // FIXME: combine econtract args!
     qs = TEH_plugin->insert_contract (TEH_plugin->cls,
                                       &rpc->purse_pub,
-                                      &rpc->contract_pub,
-                                      rpc->econtract_size,
-                                      rpc->econtract,
-                                      &rpc->econtract_sig,
+                                      &rpc->econtract.contract_pub,
+                                      rpc->econtract.econtract_size,
+                                      rpc->econtract.econtract,
+                                      &rpc->econtract.econtract_sig,
                                       &in_conflict);
     if (qs < 0)
     {
@@ -438,18 +432,18 @@ purse_transaction (void *cls,
     }
     if (in_conflict)
     {
-      struct TALER_ContractDiffiePublicP pub_ckey;
-      struct TALER_PurseContractSignatureP econtract_sig;
-      size_t econtract_size;
-      void *econtract;
+      struct TALER_EncryptedContract econtract;
       struct GNUNET_HashCode h_econtract;
 
-      qs = TEH_plugin->select_contract_by_purse (TEH_plugin->cls,
-                                                 &rpc->purse_pub,
-                                                 &pub_ckey,
-                                                 &econtract_sig,
-                                                 &econtract_size,
-                                                 &econtract);
+      /* FIXME: change API to only pass econtract
+         instead of all members! */
+      qs = TEH_plugin->select_contract_by_purse (
+        TEH_plugin->cls,
+        &rpc->purse_pub,
+        &econtract.contract_pub,
+        &econtract.econtract_sig,
+        &econtract.econtract_size,
+        &econtract.econtract);
       if (qs <= 0)
       {
         if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
@@ -463,8 +457,8 @@ purse_transaction (void *cls,
                                                "select contract");
         return GNUNET_DB_STATUS_HARD_ERROR;
       }
-      GNUNET_CRYPTO_hash (econtract,
-                          econtract_size,
+      GNUNET_CRYPTO_hash (econtract.econtract,
+                          econtract.econtract_size,
                           &h_econtract);
       *mhd_ret
         = TALER_MHD_REPLY_JSON_PACK (
@@ -475,9 +469,10 @@ purse_transaction (void *cls,
             GNUNET_JSON_pack_data_auto ("h_econtract",
                                         &h_econtract),
             GNUNET_JSON_pack_data_auto ("econtract_sig",
-                                        &econtract_sig),
+                                        &econtract.econtract_sig),
             GNUNET_JSON_pack_data_auto ("pub_ckey",
-                                        &pub_ckey));
+                                        &econtract.contract_pub));
+      GNUNET_free (econtract.econtract);
       return GNUNET_DB_STATUS_HARD_ERROR;
     }
   }
@@ -509,18 +504,9 @@ TEH_handler_reserves_purse (
                               &rpc.purse_fee),
       &no_purse_fee),
     GNUNET_JSON_spec_mark_optional (
-      GNUNET_JSON_spec_varsize ("econtract",
-                                &rpc.econtract,
-                                &rpc.econtract_size),
-      NULL),
-    GNUNET_JSON_spec_mark_optional (
-      GNUNET_JSON_spec_fixed_auto ("econtract_sig",
-                                   &rpc.econtract_sig),
-      NULL),
-    GNUNET_JSON_spec_mark_optional (
-      GNUNET_JSON_spec_fixed_auto ("contract_pub",
-                                   &rpc.contract_pub),
-      NULL),
+      TALER_JSON_spec_econtract ("econtract",
+                                 &rpc.econtract),
+      &rpc.no_econtract),
     GNUNET_JSON_spec_fixed_auto ("merge_pub",
                                  &rpc.merge_pub),
     GNUNET_JSON_spec_fixed_auto ("merge_sig",
@@ -667,13 +653,13 @@ TEH_handler_reserves_purse (
       TALER_EC_EXCHANGE_RESERVES_PURSE_MERGE_SIGNATURE_INVALID,
       NULL);
   }
-  if ( (NULL != rpc.econtract) &&
+  if ( (! rpc.no_econtract) &&
        (GNUNET_OK !=
-        TALER_wallet_econtract_upload_verify (rpc.econtract,
-                                              rpc.econtract_size,
-                                              &rpc.contract_pub,
+        TALER_wallet_econtract_upload_verify (rpc.econtract.econtract,
+                                              rpc.econtract.econtract_size,
+                                              &rpc.econtract.contract_pub,
                                               &rpc.purse_pub,
-                                              &rpc.econtract_sig)) )
+                                              &rpc.econtract.econtract_sig)) )
   {
     TALER_LOG_WARNING ("Invalid signature on /reserves/$PID/purse request\n");
     GNUNET_JSON_parse_free (spec);
diff --git a/src/include/taler_json_lib.h b/src/include/taler_json_lib.h
index b4f999001..a8ad6f243 100644
--- a/src/include/taler_json_lib.h
+++ b/src/include/taler_json_lib.h
@@ -28,6 +28,37 @@
 #include "taler_util.h"
 #include "taler_error_codes.h"
 
+
+/**
+ * Details about an encrypted contract.
+ */
+struct TALER_EncryptedContract
+{
+
+  /**
+   * Signature of the client affiming this encrypted contract.
+   */
+  struct TALER_PurseContractSignatureP econtract_sig;
+
+  /**
+   * Contract decryption key for the purse.
+   */
+  struct TALER_ContractDiffiePublicP contract_pub;
+
+  /**
+   * Encrypted contract, can be NULL.
+   */
+  void *econtract;
+
+  /**
+   * Number of bytes in @e econtract.
+   */
+  size_t econtract_size;
+
+
+};
+
+
 /**
  * Print JSON parsing related error information
  * @deprecated
@@ -172,6 +203,20 @@ TALER_JSON_pack_amount_nbo (const char *name,
 
 
 /**
+ * Generate packer instruction for a JSON field of type
+ * encrypted contract.
+ *
+ * @param name name of the field to add to the object
+ * @param econtract the encrypted contract
+ * @return json pack specification
+ */
+struct GNUNET_JSON_PackSpec
+TALER_JSON_pack_econtract (
+  const char *name,
+  const struct TALER_EncryptedContract *econtract);
+
+
+/**
  * Convert a TALER amount to a JSON object.
  *
  * @param amount the amount
@@ -238,6 +283,18 @@ TALER_JSON_spec_amount_any (const char *name,
 
 
 /**
+ * Provide specification to parse given JSON object to an encrypted contract.
+ *
+ * @param name name of the amount field in the JSON
+ * @param[out] econtract where to store the encrypted contract
+ * @return spec for parsing an amount
+ */
+struct GNUNET_JSON_Specification
+TALER_JSON_spec_econtract (const char *name,
+                           struct TALER_EncryptedContract *econtract);
+
+
+/**
  * Provide specification to parse given JSON object to an amount
  * in any currency in network byte order.
  *
diff --git a/src/json/json_helper.c b/src/json/json_helper.c
index 50d4705d5..2e5241b5a 100644
--- a/src/json/json_helper.c
+++ b/src/json/json_helper.c
@@ -235,6 +235,82 @@ TALER_JSON_spec_amount_any_nbo (const char *name,
 
 
 /**
+ * Parse given JSON object to an encrypted contract.
+ *
+ * @param cls closure, NULL
+ * @param root the json object representing data
+ * @param[out] spec where to write the data
+ * @return #GNUNET_OK upon successful parsing; #GNUNET_SYSERR upon error
+ */
+static enum GNUNET_GenericReturnValue
+parse_econtract (void *cls,
+                 json_t *root,
+                 struct GNUNET_JSON_Specification *spec)
+{
+  struct TALER_EncryptedContract *econtract = spec->ptr;
+  struct GNUNET_JSON_Specification ispec[] = {
+    GNUNET_JSON_spec_varsize ("econtract",
+                              &econtract->econtract,
+                              &econtract->econtract_size),
+    GNUNET_JSON_spec_fixed_auto ("econtract_sig",
+                                 &econtract->econtract_sig),
+    GNUNET_JSON_spec_fixed_auto ("contract_pub",
+                                 &econtract->contract_pub),
+    GNUNET_JSON_spec_end ()
+  };
+  const char *emsg;
+  unsigned int eline;
+
+  (void) cls;
+  if (GNUNET_OK !=
+      GNUNET_JSON_parse (root,
+                         ispec,
+                         &emsg,
+                         &eline))
+  {
+    GNUNET_break_op (0);
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
+/**
+ * Cleanup data left from parsing encrypted contract.
+ *
+ * @param cls closure, NULL
+ * @param[out] spec where to free the data
+ */
+static void
+clean_econtract (void *cls,
+                 struct GNUNET_JSON_Specification *spec)
+{
+  struct TALER_EncryptedContract *econtract = spec->ptr;
+
+  (void) cls;
+  GNUNET_free (econtract->econtract);
+}
+
+
+struct GNUNET_JSON_Specification
+TALER_JSON_spec_econtract (const char *name,
+                           struct TALER_EncryptedContract *econtract)
+{
+  struct GNUNET_JSON_Specification ret = {
+    .parser = &parse_econtract,
+    .cleaner = &clean_econtract,
+    .cls = NULL,
+    .field = name,
+    .ptr = econtract,
+    .ptr_size = 0,
+    .size_ptr = NULL
+  };
+
+  return ret;
+}
+
+
+/**
  * Parse given JSON object to denomination public key.
  *
  * @param cls closure, NULL
diff --git a/src/json/json_pack.c b/src/json/json_pack.c
index ad41eb955..090a8b96b 100644
--- a/src/json/json_pack.c
+++ b/src/json/json_pack.c
@@ -48,6 +48,30 @@ TALER_JSON_pack_time_abs_nbo_human (const char *name,
 
 
 struct GNUNET_JSON_PackSpec
+TALER_JSON_pack_econtract (
+  const char *name,
+  const struct TALER_EncryptedContract *econtract)
+{
+  struct GNUNET_JSON_PackSpec ps = {
+    .field_name = name,
+  };
+
+  if (NULL == econtract)
+    return ps;
+  ps.object
+    = GNUNET_JSON_PACK (
+        GNUNET_JSON_pack_data_varsize ("econtract",
+                                       econtract->econtract,
+                                       econtract->econtract_size),
+        GNUNET_JSON_pack_data_auto ("econtract_sig",
+                                    &econtract->econtract_sig),
+        GNUNET_JSON_pack_data_auto ("contract_pub",
+                                    &econtract->contract_pub));
+  return ps;
+}
+
+
+struct GNUNET_JSON_PackSpec
 TALER_JSON_pack_denom_pub (
   const char *name,
   const struct TALER_DenominationPublicKey *pk)
@@ -56,6 +80,8 @@ TALER_JSON_pack_denom_pub (
     .field_name = name,
   };
 
+  if (NULL == pk)
+    return ps;
   switch (pk->cipher)
   {
   case TALER_DENOMINATION_RSA:
@@ -95,6 +121,8 @@ TALER_JSON_pack_denom_sig (
     .field_name = name,
   };
 
+  if (NULL == sig)
+    return ps;
   switch (sig->cipher)
   {
   case TALER_DENOMINATION_RSA:
@@ -129,6 +157,8 @@ TALER_JSON_pack_exchange_withdraw_values (
     .field_name = name,
   };
 
+  if (NULL == ewv)
+    return ps;
   switch (ewv->cipher)
   {
   case TALER_DENOMINATION_RSA:
@@ -166,6 +196,8 @@ TALER_JSON_pack_blinded_denom_sig (
     .field_name = name,
   };
 
+  if (NULL == sig)
+    return ps;
   switch (sig->cipher)
   {
   case TALER_DENOMINATION_RSA:
@@ -200,6 +232,8 @@ TALER_JSON_pack_blinded_planchet (
     .field_name = name,
   };
 
+  if (NULL == blinded_planchet)
+    return ps;
   switch (blinded_planchet->cipher)
   {
   case TALER_DENOMINATION_RSA:
diff --git a/src/lib/exchange_api_purse_create_with_deposit.c b/src/lib/exchange_api_purse_create_with_deposit.c
index 42dd6914b..e77bbf2da 100644
--- a/src/lib/exchange_api_purse_create_with_deposit.c
+++ b/src/lib/exchange_api_purse_create_with_deposit.c
@@ -253,7 +253,7 @@ TALER_EXCHANGE_purse_create_with_deposit (
   json_t *deposit_arr;
   CURL *eh;
   struct TALER_PurseContractSignatureP purse_sig;
-  struct TALER_PurseContractSignatureP econtract_sig;
+  struct TALER_EncryptedContract econtract;
   struct TALER_ContractDiffiePublicP contract_pub;
   char arg_str[sizeof (pch->purse_pub) * 2 + 32];
   char *url;
@@ -311,8 +311,6 @@ TALER_EXCHANGE_purse_create_with_deposit (
                      "/purses/%s/create",
                      pub_str);
   }
-  GNUNET_CRYPTO_ecdhe_key_get_public (&contract_priv->ecdhe_priv,
-                                      &contract_pub.ecdhe_pub);
   GNUNET_CRYPTO_eddsa_key_get_public (&merge_priv->eddsa_priv,
                                       &pch->merge_pub.eddsa_pub);
   pch->url = TEAH_path_to_url (exchange,
@@ -395,58 +393,44 @@ TALER_EXCHANGE_purse_create_with_deposit (
                                   &pch->purse_value_after_fees,
                                   purse_priv,
                                   &purse_sig);
+  if (upload_contract)
   {
-    void *econtract = NULL;
-    size_t econtract_size = 0;
-
-    if (upload_contract)
-    {
-      TALER_CRYPTO_contract_encrypt_for_merge (&pch->purse_pub,
-                                               contract_priv,
-                                               merge_priv,
-                                               contract_terms,
-                                               &econtract,
-                                               &econtract_size);
-      TALER_wallet_econtract_upload_sign (econtract,
-                                          econtract_size,
-                                          &contract_pub,
-                                          purse_priv,
-                                          &econtract_sig);
-    }
-    create_obj = GNUNET_JSON_PACK (
-      TALER_JSON_pack_amount ("amount",
-                              &pch->purse_value_after_fees),
-      GNUNET_JSON_pack_uint64 ("min_age",
-                               min_age),
-      GNUNET_JSON_pack_allow_null (
-        GNUNET_JSON_pack_data_varsize ("econtract",
-                                       econtract,
-                                       econtract_size)),
-      GNUNET_JSON_pack_allow_null (
-        (upload_contract)
-        ? GNUNET_JSON_pack_data_auto ("contract_pub",
-                                      &contract_pub)
-        : GNUNET_JSON_pack_string ("dummy",
-                                   NULL)),
-      GNUNET_JSON_pack_allow_null (
-        (upload_contract)
-        ? GNUNET_JSON_pack_data_auto ("econtract_sig",
-                                      &econtract_sig)
-        : GNUNET_JSON_pack_string ("dummy2",
-                                   NULL)),
-      GNUNET_JSON_pack_data_auto ("purse_sig",
-                                  &purse_sig),
-      GNUNET_JSON_pack_data_auto ("merge_pub",
-                                  &pch->merge_pub),
-      GNUNET_JSON_pack_data_auto ("h_contract_terms",
-                                  &pch->h_contract_terms),
-      GNUNET_JSON_pack_timestamp ("purse_expiration",
-                                  pch->purse_expiration),
-      GNUNET_JSON_pack_array_steal ("deposits",
-                                    deposit_arr));
-    GNUNET_free (econtract);
+    TALER_CRYPTO_contract_encrypt_for_merge (&pch->purse_pub,
+                                             contract_priv,
+                                             merge_priv,
+                                             contract_terms,
+                                             &econtract.econtract,
+                                             &econtract.econtract_size);
+    GNUNET_CRYPTO_ecdhe_key_get_public (&contract_priv->ecdhe_priv,
+                                        &contract_pub.ecdhe_pub);
+    TALER_wallet_econtract_upload_sign (econtract.econtract,
+                                        econtract.econtract_size,
+                                        &contract_pub,
+                                        purse_priv,
+                                        &econtract.econtract_sig);
   }
+  create_obj = GNUNET_JSON_PACK (
+    TALER_JSON_pack_amount ("amount",
+                            &pch->purse_value_after_fees),
+    GNUNET_JSON_pack_uint64 ("min_age",
+                             min_age),
+    GNUNET_JSON_pack_allow_null (
+      TALER_JSON_pack_econtract ("econtract",
+                                 upload_contract
+                                  ? &econtract
+                                  : NULL)),
+    GNUNET_JSON_pack_data_auto ("purse_sig",
+                                &purse_sig),
+    GNUNET_JSON_pack_data_auto ("merge_pub",
+                                &pch->merge_pub),
+    GNUNET_JSON_pack_data_auto ("h_contract_terms",
+                                &pch->h_contract_terms),
+    GNUNET_JSON_pack_timestamp ("purse_expiration",
+                                pch->purse_expiration),
+    GNUNET_JSON_pack_array_steal ("deposits",
+                                  deposit_arr));
   GNUNET_assert (NULL != create_obj);
+  GNUNET_free (econtract.econtract);
   eh = TALER_EXCHANGE_curl_easy_get_ (pch->url);
   if ( (NULL == eh) ||
        (GNUNET_OK !=
diff --git a/src/lib/exchange_api_purse_create_with_merge.c b/src/lib/exchange_api_purse_create_with_merge.c
index fcc68e699..90301b869 100644
--- a/src/lib/exchange_api_purse_create_with_merge.c
+++ b/src/lib/exchange_api_purse_create_with_merge.c
@@ -71,6 +71,11 @@ struct TALER_EXCHANGE_PurseCreateMergeHandle
   void *cb_cls;
 
   /**
+   * The encrypted contract (if any).
+   */
+  struct TALER_EncryptedContract econtract;
+
+  /**
    * Expected value in the purse after fees.
    */
   struct TALER_Amount purse_value_after_fees;
@@ -96,11 +101,6 @@ struct TALER_EXCHANGE_PurseCreateMergeHandle
   struct TALER_PurseMergeSignatureP merge_sig;
 
   /**
-   * Our contract signature (if any).
-   */
-  struct TALER_PurseContractSignatureP contract_sig;
-
-  /**
    * Public key of the purse.
    */
   struct TALER_PurseContractPublicKeyP purse_pub;
@@ -391,7 +391,7 @@ handle_purse_create_with_merge_finished (void *cls,
         }
         if (0 ==
             GNUNET_memcmp (&contract_sig,
-                           &pcm->contract_sig))
+                           &pcm->econtract.econtract_sig))
         {
           /* Must be the SAME data, not a conflict! */
           GNUNET_break_op (0);
@@ -466,9 +466,6 @@ TALER_EXCHANGE_purse_create_with_merge (
   CURL *eh;
   char arg_str[sizeof (pcm->reserve_pub) * 2 + 32];
   uint32_t min_age = 0;
-  struct TALER_ContractDiffiePublicP contract_pub;
-  void *econtract = NULL;
-  size_t econtract_size = 0;
   struct TALER_Amount purse_fee;
   enum TALER_WalletAccountMergeFlags flags;
 
@@ -492,8 +489,6 @@ TALER_EXCHANGE_purse_create_with_merge (
                                       &pcm->reserve_pub.eddsa_pub);
   GNUNET_CRYPTO_eddsa_key_get_public (&merge_priv->eddsa_priv,
                                       &pcm->merge_pub.eddsa_pub);
-  GNUNET_CRYPTO_ecdhe_key_get_public (&contract_priv->ecdhe_priv,
-                                      &contract_pub.ecdhe_pub);
 
   {
     struct GNUNET_JSON_Specification spec[] = {
@@ -588,14 +583,16 @@ TALER_EXCHANGE_purse_create_with_merge (
       &pcm->purse_pub,
       contract_priv,
       contract_terms,
-      &econtract,
-      &econtract_size);
+      &pcm->econtract.econtract,
+      &pcm->econtract.econtract_size);
+    GNUNET_CRYPTO_ecdhe_key_get_public (&contract_priv->ecdhe_priv,
+                                        &pcm->econtract.contract_pub.ecdhe_pub);
     TALER_wallet_econtract_upload_sign (
-      econtract,
-      econtract_size,
-      &contract_pub,
+      pcm->econtract.econtract,
+      pcm->econtract.econtract_size,
+      &pcm->econtract.contract_pub,
       purse_priv,
-      &pcm->contract_sig);
+      &pcm->econtract.econtract_sig);
   }
   create_with_merge_obj = GNUNET_JSON_PACK (
     TALER_JSON_pack_amount ("purse_value",
@@ -603,21 +600,10 @@ TALER_EXCHANGE_purse_create_with_merge (
     GNUNET_JSON_pack_uint64 ("min_age",
                              min_age),
     GNUNET_JSON_pack_allow_null (
-      GNUNET_JSON_pack_data_varsize ("econtract",
-                                     econtract,
-                                     econtract_size)),
-    GNUNET_JSON_pack_allow_null (
-      upload_contract
-      ? GNUNET_JSON_pack_data_auto ("econtract_sig",
-                                    &pcm->contract_sig)
-      : GNUNET_JSON_pack_string ("dummy",
-                                 NULL)),
-    GNUNET_JSON_pack_allow_null (
-      upload_contract
-      ? GNUNET_JSON_pack_data_auto ("contract_pub",
-                                    &contract_pub)
-      : GNUNET_JSON_pack_string ("dummy",
-                                 NULL)),
+      TALER_JSON_pack_econtract ("econtract",
+                                 upload_contract
+                                  ? &pcm->econtract
+                                  : NULL)),
     GNUNET_JSON_pack_allow_null (
       pay_for_purse
       ? TALER_JSON_pack_amount ("purse_fee",
@@ -641,7 +627,6 @@ TALER_EXCHANGE_purse_create_with_merge (
     GNUNET_JSON_pack_timestamp ("purse_expiration",
                                 pcm->purse_expiration));
   GNUNET_assert (NULL != create_with_merge_obj);
-  GNUNET_free (econtract);
   eh = TALER_EXCHANGE_curl_easy_get_ (pcm->url);
   if ( (NULL == eh) ||
        (GNUNET_OK !=
@@ -653,6 +638,7 @@ TALER_EXCHANGE_purse_create_with_merge (
     if (NULL != eh)
       curl_easy_cleanup (eh);
     json_decref (create_with_merge_obj);
+    GNUNET_free (pcm->econtract.econtract);
     GNUNET_free (pcm->url);
     GNUNET_free (pcm);
     return NULL;
@@ -682,6 +668,7 @@ TALER_EXCHANGE_purse_create_with_merge_cancel (
   }
   GNUNET_free (pcm->url);
   TALER_curl_easy_post_finished (&pcm->ctx);
+  GNUNET_free (pcm->econtract.econtract);
   GNUNET_free (pcm);
 }