include fees in amounts being signed, check available balance on refresh

10 files changed, 183 insertions, 111 deletions

diff --git a/src/include/taler_signatures.h b/src/include/taler_signatures.h
index b91639321..4566764d0 100644
--- a/src/include/taler_signatures.h
+++ b/src/include/taler_signatures.h
@@ -132,6 +132,15 @@ struct TALER_WithdrawRequest
   struct GNUNET_CRYPTO_EddsaPublicKey reserve_pub;
 
   /**
+   * Value of the coin being minted (matching the denomination key)
+   * plus the transaction fee.  We include this in what is being
+   * signed so that we can verify a reserve's remaining total balance
+   * without needing to access the respective denomination key
+   * information each time.
+   */
+  struct TALER_AmountNBO amount_with_fee;
+
+  /**
    * Hash of the denomination public key for the coin that is withdrawn.
    */
   struct GNUNET_HashCode h_denomination_pub;
@@ -171,9 +180,11 @@ struct TALER_DepositRequest
   uint64_t transaction_id GNUNET_PACKED;
 
   /**
-   * Amount to be deposited.
+   * Amount to be deposited, including fee.
    */
-  struct TALER_AmountNBO amount;
+  struct TALER_AmountNBO amount_with_fee;
+  /* FIXME: we should probably also include the value of
+     the depositing fee here as well! */
 
   /**
    * The coin's public key.
@@ -211,9 +222,12 @@ struct TALER_DepositConfirmation
   uint64_t transaction_id GNUNET_PACKED;
 
   /**
-   * Amount to be deposited.
+   * Amount to be deposited, including fee.
    */
-  struct TALER_AmountNBO amount;
+  struct TALER_AmountNBO amount_with_fee;
+
+  /* FIXME: we should probably also include the value of
+     the depositing fee here as well! */
 
   /**
    * The coin's public key.
@@ -245,11 +259,17 @@ struct RefreshMeltCoinSignature
   struct GNUNET_HashCode melt_hash;
 
   /**
-   * How much of the value of the coin should be melted?
-   * This amount includes the fees, so the final amount contributed
-   * to the melt is this value minus the fee for melting the coin.
+   * How much of the value of the coin should be melted?  This amount
+   * includes the fees, so the final amount contributed to the melt is
+   * this value minus the fee for melting the coin.  We include the
+   * fee in what is being signed so that we can verify a reserve's
+   * remaining total balance without needing to access the respective
+   * denomination key information each time.
    */
-  struct TALER_AmountNBO amount;
+  struct TALER_AmountNBO amount_with_fee;
+
+  /* FIXME: we should probably also include the value of
+     the melting fee here as well! */
 
   /**
    * The coin's public key.
@@ -282,9 +302,13 @@ struct RefreshMeltSessionSignature
 
   /**
    * What is the total value of the coins created during the
-   * refresh, excluding fees?
+   * refresh, including melting fee!
    */
-  struct TALER_AmountNBO amount;
+  struct TALER_AmountNBO amount_with_fee;
+
+  /* FIXME: we should probably also include the value of
+     the melting fee here as well! */
+
 };
 
 
diff --git a/src/mint/plugin_mintdb_postgres.c b/src/mint/plugin_mintdb_postgres.c
index 16b134350..1d7a965cf 100644
--- a/src/mint/plugin_mintdb_postgres.c
+++ b/src/mint/plugin_mintdb_postgres.c
@@ -1401,7 +1401,7 @@ postgres_insert_deposit (void *cls,
                                           &denom_sig_enc);
   json_wire_enc = json_dumps (deposit->wire, JSON_COMPACT);
   TALER_amount_hton (&amount_nbo,
-                     &deposit->amount);
+                     &deposit->amount_with_fee);
   struct TALER_DB_QueryParam params[]= {
     TALER_DB_QUERY_PARAM_PTR (&deposit->coin.coin_pub),
     TALER_DB_QUERY_PARAM_PTR_SIZED (denom_pub_enc, denom_pub_enc_size),
diff --git a/src/mint/taler-mint-httpd_db.c b/src/mint/taler-mint-httpd_db.c
index d347126d9..b3e239c89 100644
--- a/src/mint/taler-mint-httpd_db.c
+++ b/src/mint/taler-mint-httpd_db.c
@@ -35,6 +35,64 @@
 
 
 /**
+ * Calculate the total value of all transactions performed.
+ * Stores @a off plus the cost of all transactions in @a tl
+ * in @a ret.
+ *
+ * @param pos transaction list to process
+ * @param off offset to use as the starting value
+ * @param ret where the resulting total is to be stored
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR on errors
+ */
+static int
+calculate_transaction_list_totals (struct TALER_MINT_DB_TransactionList *tl,
+                                   const struct TALER_Amount *off,
+                                   struct TALER_Amount *ret)
+{
+  struct TALER_Amount spent = *off;
+  struct TALER_MINT_DB_TransactionList *pos;
+
+  for (pos = tl; NULL != pos; pos = pos->next)
+  {
+    switch (pos->type)
+    {
+    case TALER_MINT_DB_TT_DEPOSIT:
+      if (GNUNET_OK !=
+          TALER_amount_add (&spent,
+                            &spent,
+                            &pos->details.deposit->amount_with_fee))
+      {
+        GNUNET_break (0);
+        return GNUNET_SYSERR;
+      }
+      break;
+    case TALER_MINT_DB_TT_REFRESH_MELT:
+      if (GNUNET_OK !=
+          TALER_amount_add (&spent,
+                            &spent,
+                            &pos->details.melt->amount_with_fee))
+      {
+        GNUNET_break (0);
+        return GNUNET_SYSERR;
+      }
+      break;
+    case TALER_MINT_DB_TT_LOCK:
+      /* should check if lock is still active,
+         and if it is for THIS operation; if
+         lock is inactive, delete it; if lock
+         is for THIS operation, ignore it;
+         if lock is for another operation,
+         count it! */
+      GNUNET_assert (0);  // FIXME: not implemented! (#3625)
+      return GNUNET_SYSERR;
+    }
+  }
+  *ret = spent;
+  return GNUNET_OK;
+}
+
+
+/**
  * Execute a deposit.  The validity of the coin and signature
  * have already been checked.  The database must now check that
  * the coin is not (double or over) spent, and execute the
@@ -50,11 +108,9 @@ TALER_MINT_db_execute_deposit (struct MHD_Connection *connection,
 {
   struct TALER_MINTDB_Session *session;
   struct TALER_MINT_DB_TransactionList *tl;
-  struct TALER_MINT_DB_TransactionList *pos;
   struct TALER_Amount spent;
   struct TALER_Amount value;
   struct TALER_Amount fee_deposit;
-  struct TALER_Amount fee_refresh;
   struct MintKeyState *mks;
   struct TALER_MINT_DenomKeyIssuePriv *dki;
   int ret;
@@ -76,7 +132,7 @@ TALER_MINT_db_execute_deposit (struct MHD_Connection *connection,
                                              &deposit->h_contract,
                                              deposit->transaction_id,
                                              &deposit->merchant_pub,
-                                             &deposit->amount);
+                                             &deposit->amount_with_fee);
   }
   mks = TALER_MINT_key_state_acquire ();
   dki = TALER_MINT_get_denom_key (mks,
@@ -85,8 +141,6 @@ TALER_MINT_db_execute_deposit (struct MHD_Connection *connection,
                      &dki->issue.value);
   TALER_amount_ntoh (&fee_deposit,
                      &dki->issue.fee_deposit);
-  TALER_amount_ntoh (&fee_refresh,
-                     &dki->issue.fee_refresh);
   TALER_MINT_key_state_release (mks);
 
   if (GNUNET_OK !=
@@ -96,69 +150,29 @@ TALER_MINT_db_execute_deposit (struct MHD_Connection *connection,
     GNUNET_break (0);
     return TALER_MINT_reply_internal_db_error (connection);
   }
+  /* fee for THIS transaction */
+  spent = deposit->amount_with_fee;
+  if (TALER_amount_cmp (&fee_deposit,
+                        &spent) < 0)
+  {
+    return (MHD_YES ==
+            TALER_MINT_reply_external_error (connection,
+                                             "deposited amount smaller than depositing fee"))
+      ? GNUNET_NO : GNUNET_SYSERR;
+  }
+  /* add cost of all previous transactions */
   tl = plugin->get_coin_transactions (plugin->cls,
                                       session,
                                       &deposit->coin.coin_pub);
-  spent = fee_deposit; /* fee for THIS transaction */
   if (GNUNET_OK !=
-      TALER_amount_add (&spent,
-                        &spent,
-                        &deposit->amount))
+      calculate_transaction_list_totals (tl,
+                                         &spent,
+                                         &spent))
   {
-    GNUNET_break (0);
     plugin->free_coin_transaction_list (plugin->cls,
                                         tl);
     return TALER_MINT_reply_internal_db_error (connection);
   }
-
-  for (pos = tl; NULL != pos; pos = pos->next)
-  {
-    switch (pos->type)
-    {
-    case TALER_MINT_DB_TT_DEPOSIT:
-      if ( (GNUNET_OK !=
-            TALER_amount_add (&spent,
-                              &spent,
-                              &pos->details.deposit->amount)) ||
-           (GNUNET_OK !=
-            TALER_amount_add (&spent,
-                              &spent,
-                              &fee_deposit)) )
-      {
-        GNUNET_break (0);
-        plugin->free_coin_transaction_list (plugin->cls,
-                                            tl);
-        return TALER_MINT_reply_internal_db_error (connection);
-      }
-      break;
-    case TALER_MINT_DB_TT_REFRESH_MELT:
-      if ( (GNUNET_OK !=
-            TALER_amount_add (&spent,
-                              &spent,
-                              &pos->details.melt->amount)) ||
-           (GNUNET_OK !=
-            TALER_amount_add (&spent,
-                              &spent,
-                              &fee_refresh)) )
-      {
-        GNUNET_break (0);
-        plugin->free_coin_transaction_list (plugin->cls,
-                                            tl);
-        return TALER_MINT_reply_internal_db_error (connection);
-      }
-      break;
-    case TALER_MINT_DB_TT_LOCK:
-      /* should check if lock is still active,
-         and if it is for THIS operation; if
-         lock is inactive, delete it; if lock
-         is for THIS operation, ignore it;
-         if lock is for another operation,
-         count it! */
-      GNUNET_assert (0);  // FIXME: not implemented! (#3625)
-      break;
-    }
-  }
-
   if (0 < TALER_amount_cmp (&spent,
                             &value))
   {
@@ -197,7 +211,7 @@ TALER_MINT_db_execute_deposit (struct MHD_Connection *connection,
                                            &deposit->h_contract,
                                            deposit->transaction_id,
                                            &deposit->merchant_pub,
-                                           &deposit->amount);
+                                           &deposit->amount_with_fee);
 }
 
 
@@ -501,8 +515,11 @@ refresh_accept_melts (struct MHD_Connection *connection,
 {
   struct TALER_MINT_DenomKeyIssue *dki;
   struct TALER_MINT_DB_TransactionList *tl;
+  struct TALER_Amount fee_deposit;
+  struct TALER_Amount fee_refresh;
   struct TALER_Amount coin_value;
   struct TALER_Amount coin_residual;
+  struct TALER_Amount spent;
   struct RefreshMelt melt;
   int res;
 
@@ -518,26 +535,51 @@ refresh_accept_melts (struct MHD_Connection *connection,
                                         "denom not found"))
       ? GNUNET_NO : GNUNET_SYSERR;
 
+  TALER_amount_ntoh (&fee_deposit,
+                     &dki->fee_deposit);
+  TALER_amount_ntoh (&fee_refresh,
+                     &dki->fee_refresh);
   TALER_amount_ntoh (&coin_value,
                      &dki->value);
+  /* fee for THIS transaction; the melt amount includes the fee! */
+  spent = coin_details->melt_amount_with_fee;
+  if (TALER_amount_cmp (&fee_refresh,
+                        &spent) < 0)
+  {
+    return (MHD_YES ==
+            TALER_MINT_reply_external_error (connection,
+                                             "melt amount smaller than melting fee"))
+      ? GNUNET_NO : GNUNET_SYSERR;
+  }
+  /* add historic transaction costs of this coin */
   tl = plugin->get_coin_transactions (plugin->cls,
                                       session,
                                       &coin_public_info->coin_pub);
-  /* FIXME: #3636: compute how much value is left with this coin and
-     compare to `expected_value`! (subtract from "coin_value") */
-  coin_residual = coin_value;
+  if (GNUNET_OK !=
+      calculate_transaction_list_totals (tl,
+                                         &spent,
+                                         &spent))
+  {
+    GNUNET_break (0);
+    plugin->free_coin_transaction_list (plugin->cls,
+                                        tl);
+    return TALER_MINT_reply_internal_db_error (connection);
+  }
   /* Refuse to refresh when the coin does not have enough money left to
    * pay the refreshing fees of the coin. */
-
-  if (TALER_amount_cmp (&coin_residual,
-                        &coin_details->melt_amount) < 0)
+  if (TALER_amount_cmp (&coin_value,
+                        &spent) < 0)
   {
+    GNUNET_assert (GNUNET_OK ==
+                   TALER_amount_subtract (&coin_residual,
+                                          &spent,
+                                          &coin_details->melt_amount_with_fee));
     res = (MHD_YES ==
            TALER_MINT_reply_refresh_melt_insufficient_funds (connection,
                                                              &coin_public_info->coin_pub,
                                                              coin_value,
                                                              tl,
-                                                             coin_details->melt_amount,
+                                                             coin_details->melt_amount_with_fee,
                                                              coin_residual))
       ? GNUNET_NO : GNUNET_SYSERR;
     plugin->free_coin_transaction_list (plugin->cls,
@@ -550,7 +592,7 @@ refresh_accept_melts (struct MHD_Connection *connection,
   melt.coin = *coin_public_info;
   melt.coin_sig = coin_details->melt_sig;
   melt.melt_hash = *melt_hash;
-  melt.amount = coin_details->melt_amount;
+  melt.amount_with_fee = coin_details->melt_amount_with_fee;
   if (GNUNET_OK !=
       plugin->insert_refresh_melt (plugin->cls,
                                    session,
diff --git a/src/mint/taler-mint-httpd_db.h b/src/mint/taler-mint-httpd_db.h
index aefbfc424..52e86f898 100644
--- a/src/mint/taler-mint-httpd_db.h
+++ b/src/mint/taler-mint-httpd_db.h
@@ -95,7 +95,7 @@ struct MeltDetails
    * This amount includes the fees, so the final amount contributed
    * to the melt is this value minus the fee for melting the coin.
    */
-  struct TALER_Amount melt_amount;
+  struct TALER_Amount melt_amount_with_fee;
 };
 
 
diff --git a/src/mint/taler-mint-httpd_deposit.c b/src/mint/taler-mint-httpd_deposit.c
index e411e0d8e..647cd8242 100644
--- a/src/mint/taler-mint-httpd_deposit.c
+++ b/src/mint/taler-mint-httpd_deposit.c
@@ -65,8 +65,8 @@ verify_and_execute_deposit (struct MHD_Connection *connection,
   dr.h_contract = deposit->h_contract;
   dr.h_wire = deposit->h_wire;
   dr.transaction_id = GNUNET_htonll (deposit->transaction_id);
-  TALER_amount_hton (&dr.amount,
-                     &deposit->amount);
+  TALER_amount_hton (&dr.amount_with_fee,
+                     &deposit->amount_with_fee);
   dr.coin_pub = deposit->coin.coin_pub;
   if (GNUNET_OK !=
       GNUNET_CRYPTO_ecdsa_verify (TALER_SIGNATURE_WALLET_DEPOSIT,
@@ -167,7 +167,7 @@ parse_and_handle_deposit_request (struct MHD_Connection *connection,
   GNUNET_free (wire_enc);
 
   deposit.wire = wire;
-  deposit.amount = *amount;
+  deposit.amount_with_fee = *amount;
   res = verify_and_execute_deposit (connection,
                                     &deposit);
   TALER_MINT_release_parsed_data (spec);
diff --git a/src/mint/taler-mint-httpd_refresh.c b/src/mint/taler-mint-httpd_refresh.c
index d4979288d..602fc67f6 100644
--- a/src/mint/taler-mint-httpd_refresh.c
+++ b/src/mint/taler-mint-httpd_refresh.c
@@ -109,8 +109,8 @@ handle_refresh_melt_binary (struct MHD_Connection *connection,
   body.purpose.purpose = htonl (TALER_SIGNATURE_REFRESH_MELT_SESSION);
   body.purpose.size = htonl (sizeof (struct RefreshMeltSessionSignature));
   body.melt_hash = melt_hash;
-  TALER_amount_hton (&body.amount,
-                     &coin_melt_details->melt_amount);
+  TALER_amount_hton (&body.amount_with_fee,
+                     &coin_melt_details->melt_amount_with_fee);
 
   if (GNUNET_OK != GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_REFRESH_MELT_SESSION,
                                                &body.purpose,
@@ -252,7 +252,7 @@ get_coin_public_info (struct MHD_Connection *connection,
       ? GNUNET_NO : GNUNET_SYSERR;
   }
   r_melt_detail->melt_sig = melt_sig;
-  r_melt_detail->melt_amount = amount;
+  r_melt_detail->melt_amount_with_fee = amount;
   TALER_MINT_release_parsed_data (spec);
   return GNUNET_OK;
 }
@@ -288,8 +288,8 @@ verify_coin_public_info (struct MHD_Connection *connection,
   body.purpose.size = htonl (sizeof (struct RefreshMeltCoinSignature));
   body.purpose.purpose = htonl (TALER_SIGNATURE_REFRESH_MELT_COIN);
   body.melt_hash = *melt_hash;
-  TALER_amount_hton (&body.amount,
-                     &r_melt_detail->melt_amount);
+  TALER_amount_hton (&body.amount_with_fee,
+                     &r_melt_detail->melt_amount_with_fee);
   body.coin_pub = r_public_info->coin_pub;
   if (GNUNET_OK !=
       GNUNET_CRYPTO_ecdsa_verify (TALER_SIGNATURE_REFRESH_MELT_COIN,
diff --git a/src/mint/taler-mint-httpd_responses.c b/src/mint/taler-mint-httpd_responses.c
index a4b442152..681b2b922 100644
--- a/src/mint/taler-mint-httpd_responses.c
+++ b/src/mint/taler-mint-httpd_responses.c
@@ -299,7 +299,7 @@ TALER_MINT_reply_deposit_success (struct MHD_Connection *connection,
   dc.h_contract = *h_contract;
   dc.h_wire = *h_wire;
   dc.transaction_id = GNUNET_htonll (transaction_id);
-  TALER_amount_hton (&dc.amount,
+  TALER_amount_hton (&dc.amount_with_fee,
                      amount);
   dc.coin_pub = *coin_pub;
   dc.merchant = *merchant;
@@ -341,14 +341,14 @@ compile_transaction_history (const struct TALER_MINT_DB_TransactionList *tl)
         const struct Deposit *deposit = pos->details.deposit;
 
         type = "deposit";
-        value = deposit->amount;
+        value = deposit->amount_with_fee;
         dr.purpose.purpose = htonl (TALER_SIGNATURE_WALLET_DEPOSIT);
         dr.purpose.size = htonl (sizeof (struct TALER_DepositRequest));
         dr.h_contract = deposit->h_contract;
         dr.h_wire = deposit->h_wire;
         dr.transaction_id = GNUNET_htonll (deposit->transaction_id);
-        TALER_amount_hton (&dr.amount,
-                           &deposit->amount);
+        TALER_amount_hton (&dr.amount_with_fee,
+                           &deposit->amount_with_fee);
         dr.coin_pub = deposit->coin.coin_pub;
         transaction = TALER_JSON_from_ecdsa_sig (&dr.purpose,
                                                  &deposit->csig);
@@ -360,12 +360,12 @@ compile_transaction_history (const struct TALER_MINT_DB_TransactionList *tl)
         const struct RefreshMelt *melt = pos->details.melt;
 
         type = "melt";
-        value = melt->amount;
+        value = melt->amount_with_fee;
         ms.purpose.purpose = htonl (TALER_SIGNATURE_REFRESH_MELT_COIN);
         ms.purpose.size = htonl (sizeof (struct RefreshMeltCoinSignature));
         ms.melt_hash = melt->melt_hash;
-        TALER_amount_hton (&ms.amount,
-                           &melt->amount);
+        TALER_amount_hton (&ms.amount_with_fee,
+                           &melt->amount_with_fee);
         ms.coin_pub = melt->coin.coin_pub;
         transaction = TALER_JSON_from_ecdsa_sig (&ms.purpose,
                                                  &melt->coin_sig);
diff --git a/src/mint/taler_mintdb_plugin.h b/src/mint/taler_mintdb_plugin.h
index bc5cd69a6..83e373340 100644
--- a/src/mint/taler_mintdb_plugin.h
+++ b/src/mint/taler_mintdb_plugin.h
@@ -14,13 +14,13 @@
   TALER; see the file COPYING.  If not, If not, see <http://www.gnu.org/licenses/>
 */
 /**
- * @file mint/mint_db.h
+ * @file mint/taler_mintdb_plugin.h
  * @brief Low-level (statement-level) database access for the mint
  * @author Florian Dold
  * @author Christian Grothoff
  */
-#ifndef MINT_DB_H
-#define MINT_DB_H
+#ifndef TALER_MINTDB_PLUGIN_H
+#define TALER_MINTDB_PLUGIN_H
 
 #include <gnunet/gnunet_util_lib.h>
 #include "taler_util.h"
@@ -87,6 +87,9 @@ struct CollectableBlindcoin
 
   /**
    * Denomination key (which coin was generated).
+   * FIXME: we should probably instead have the
+   * AMOUNT *including* fee in what is being signed
+   * as well!
    */
   struct GNUNET_CRYPTO_rsa_PublicKey *denom_pub;
 
@@ -217,10 +220,10 @@ struct Deposit
   uint64_t transaction_id;
 
   /**
-   * Fraction of the coin's remaining value to be deposited.
-   * The coin is identified by @e coin_pub.
+   * Fraction of the coin's remaining value to be deposited, including
+   * depositing fee (if any).  The coin is identified by @e coin_pub.
    */
-  struct TALER_Amount amount;
+  struct TALER_Amount amount_with_fee;
 
 };
 
@@ -296,11 +299,14 @@ struct RefreshMelt
   struct GNUNET_HashCode melt_hash;
 
   /**
-   * How much value is being melted?
-   * This amount includes the fees, so the final amount contributed
-   * to the melt is this value minus the fee for melting the coin.
+   * How much value is being melted?  This amount includes the fees,
+   * so the final amount contributed to the melt is this value minus
+   * the fee for melting the coin.  We include the fee in what is
+   * being signed so that we can verify a reserve's remaining total
+   * balance without needing to access the respective denomination key
+   * information each time.
    */
-  struct TALER_Amount amount;
+  struct TALER_Amount amount_with_fee;
 
 };
 
@@ -397,7 +403,7 @@ struct Lock
   const struct GNUNET_CRYPTO_EcdsaSignature coin_sig;
 
   /**
-   * How much value is being melted?
+   * How much value is being locked?
    */
   struct TALER_Amount amount;
 
diff --git a/src/mint/test_mint_db.c b/src/mint/test_mint_db.c
index e4d312927..c80be70c3 100644
--- a/src/mint/test_mint_db.c
+++ b/src/mint/test_mint_db.c
@@ -286,7 +286,7 @@ run (void *cls,
   deposit.wire = wire;
   deposit.transaction_id =
       GNUNET_CRYPTO_random_u64 (GNUNET_CRYPTO_QUALITY_WEAK, UINT64_MAX);
-  deposit.amount = amount;
+  deposit.amount_with_fee = amount;
   FAILIF (GNUNET_OK !=
           plugin->insert_deposit (plugin->cls,
                                   session, &deposit));
diff --git a/src/mint/test_mint_deposits.c b/src/mint/test_mint_deposits.c
index c829e6e10..4107c1aee 100644
--- a/src/mint/test_mint_deposits.c
+++ b/src/mint/test_mint_deposits.c
@@ -94,12 +94,12 @@ run (void *cls,
                                              UINT64_MAX);
   deposit->transaction_id = GNUNET_htonll (transaction_id);
   /* Random amount */
-  deposit->amount.value =
+  deposit->amount_with_fee.value =
       htonl (GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, UINT32_MAX));
-  deposit->amount.fraction =
+  deposit->amount_with_fee.fraction =
       htonl (GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, UINT32_MAX));
-  GNUNET_assert (strlen (MINT_CURRENCY) < sizeof (deposit->amount.currency));
-  strcpy (deposit->amount.currency, MINT_CURRENCY);
+  GNUNET_assert (strlen (MINT_CURRENCY) < sizeof (deposit->amount_with_fee.currency));
+  strcpy (deposit->amount_with_fee.currency, MINT_CURRENCY);
   /* Copy wireformat */
   deposit->wire = json_loads (wire, 0, NULL);
   EXITIF (GNUNET_OK !=