Merge branch 'master' of git.taler.net:/var/git/exchange

12 files changed, 614 insertions, 269 deletions

diff --git a/ChangeLog b/ChangeLog
index a40af772e..af960b86f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Jun 13 16:35:09 CEST 2016
+	Splitting HTTP service to run on different listen
+	sockets for /admin and /test-APIs and the normal public
+	APIs (#4569). -CG
+
 Thu Jun  9 19:17:02 CEST 2016
 	Rename /deposit/wtid to /track/transaction and
 	/wire/deposits to /track/transfer. -CG
diff --git a/src/benchmark/taler-exchange-benchmark.c b/src/benchmark/taler-exchange-benchmark.c
index c47b352b8..93df0ae0d 100644
--- a/src/benchmark/taler-exchange-benchmark.c
+++ b/src/benchmark/taler-exchange-benchmark.c
@@ -52,12 +52,11 @@ static unsigned int nreserves;
 
 /**
  * How many coins are in `coins` array. This is needed
- * as the number of coins is not always nreserves * COINS_PER_RESERVE 
+ * as the number of coins is not always nreserves * COINS_PER_RESERVE
  * due to refresh operations
  */
 unsigned int ncoins;
 
-
 /**
  * Bank details of who creates reserves
  */
@@ -87,6 +86,11 @@ struct RefreshRevealCls {
    * Which coin in the list are we melting
    */
   unsigned int coin_index;
+
+  /**
+   * Array of denominations expected to get from melt
+   */
+  struct TALER_Amount *denoms;
 };
 
 /**
@@ -168,6 +172,12 @@ struct Coin {
   unsigned int refresh;
 
   /**
+   * If the coin has to be refreshed, this value indicates
+   * how much is left on this coin
+   */
+  struct TALER_Amount left;
+
+  /**
    * Refresh melt handle
    */
   struct TALER_EXCHANGE_RefreshMeltHandle *rmh;
@@ -179,7 +189,6 @@ struct Coin {
 
 };
 
-
 /**
  * Handle to the exchange's process
  */
@@ -216,16 +225,6 @@ static struct Reserve *reserves;
 static struct Coin *coins;
 
 /**
- * Indices of spent coins
- */
-static unsigned int *spent_coins;
-
-/**
- * Current number of spent coins
- */
-static unsigned int spent_coins_size = 0;
-
-/**
  * Transaction id counter, used in /deposit's
  */
 static unsigned int transaction_id = 0;
@@ -412,29 +411,31 @@ reveal_cb (void *cls,
     return;
   }
   else
+  {
     GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                 "Coin #%d revealed!\n",
                 rrcls->coin_index);
+    coins[rrcls->coin_index].left.value = 0;
+  }
+
   keys = TALER_EXCHANGE_get_keys (exchange);
   for (i=0; i<num_coins; i++)
   {
     struct Coin fresh_coin;
-    struct TALER_Amount amount;
-    char *refresh_denom;
-    
-    GNUNET_asprintf (&refresh_denom,
-                     "%s:%s",
-                     currency,
-                     refresh_denoms[i]);
+    char *revealed_str;
+
+    revealed_str = TALER_amount_to_string (&rrcls->denoms[i]);
+    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                "revealing %s "
+                "# of coins after refresh: %d\n",
+                revealed_str,
+                ncoins);
+
+    GNUNET_free (revealed_str);
     fresh_coin.reserve_index = coins[rrcls->coin_index].reserve_index;
-    TALER_string_to_amount (refresh_denom, &amount);
-    GNUNET_free (refresh_denom);
-    fresh_coin.pk = find_pk (keys, &amount);
+    fresh_coin.pk = find_pk (keys, &rrcls->denoms[i]);
     fresh_coin.sig = sigs[i];
     GNUNET_array_append (coins, ncoins, fresh_coin);
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "# of coins after refresh: %d\n",
-                ncoins);
   }
   GNUNET_free (rrcls);
 }
@@ -457,8 +458,8 @@ melt_cb (void *cls,
          const struct TALER_ExchangePublicKeyP *exchange_pub,
          const json_t *full_response)
 {
+  /* free'd in `reveal_cb` */
   struct RefreshRevealCls *rrcls = cls;
-  /* FIXME to be freed */
 
   coins[rrcls->coin_index].rmh = NULL;
   if (MHD_HTTP_OK != http_status)
@@ -467,12 +468,13 @@ melt_cb (void *cls,
     fail ("Coin not correctly melted!\n");
     return;
   }
+
   coins[rrcls->coin_index].rrh
     = TALER_EXCHANGE_refresh_reveal (exchange,
                                      rrcls->blob_size,
                                      rrcls->blob,
                                      noreveal_index,
-                                     reveal_cb,
+                                     &reveal_cb,
                                      rrcls);
 }
 
@@ -519,30 +521,52 @@ deposit_cb (void *cls,
     fail ("At least one coin has not been deposited, status: %d\n");
     return;
   }
-  GNUNET_log (GNUNET_ERROR_TYPE_INFO, "Coin #%d correctly spent!\n", coin_index);
-  GNUNET_array_append (spent_coins, spent_coins_size, coin_index);
-  spent_coins_size++;
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "Coin #%d correctly spent!\n",
+              coin_index);
   if (GNUNET_YES == coins[coin_index].refresh)
   {
-    struct TALER_Amount melt_amount;
     struct RefreshRevealCls *rrcls;
-
-    TALER_amount_get_zero (currency, &melt_amount);
-    melt_amount.value = 7;
     char *blob;
     size_t blob_size;
-
+    const struct TALER_EXCHANGE_Keys *keys;
+    struct TALER_Amount *denoms = NULL;
+    struct TALER_EXCHANGE_DenomPublicKey *dpks = NULL;
+    const struct TALER_EXCHANGE_DenomPublicKey *curr_dpk;
+    struct TALER_Amount curr;
+    unsigned int ndenoms = 0;
+    unsigned int ndenoms2 = 0;
+    unsigned long long acc_value;
+
+    TALER_amount_get_zero (currency, &curr);
+    curr.value = COIN_VALUE >> 1;
+    acc_value = 0;
+
+    keys = TALER_EXCHANGE_get_keys (exchange);
+    for (; curr.value > 0; curr.value = curr.value >> 1)
+    {
+      if (acc_value + curr.value <= coins[coin_index].left.value)
+      {
+        GNUNET_array_append (denoms, ndenoms, curr);
+        GNUNET_assert (NULL != (curr_dpk = find_pk (keys, &curr)));
+        GNUNET_array_append (dpks, ndenoms2, *curr_dpk);
+        acc_value += curr.value; 
+      }
+    }
+    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                "# of coins to get in melt: %d\n",
+                ndenoms2);
     blob = TALER_EXCHANGE_refresh_prepare (&coins[coin_index].coin_priv,
-                                           &melt_amount,
+                                           &coins[coin_index].left,
                                            &coins[coin_index].sig,
                                            coins[coin_index].pk,
                                            GNUNET_YES,
-                                           refresh_pk_len,
-                                           refresh_pk,
+                                           ndenoms2,
+                                           dpks,
                                            &blob_size);
     if (NULL == blob)
     {
-      fail ("Failed to prepare refresh");
+      fail ("Failed to prepare refresh\n");
       return;
     }
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
@@ -550,14 +574,11 @@ deposit_cb (void *cls,
                 (unsigned int) blob_size);
     refreshed_once = GNUNET_YES;
 
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "# of coins to get in melt: %d\n",
-                refresh_pk_len);
     rrcls = GNUNET_new (struct RefreshRevealCls);
     rrcls->blob = blob;
     rrcls->blob_size = blob_size;
     rrcls->coin_index = coin_index;
-
+    rrcls->denoms = denoms;
     coins[coin_index].rmh = TALER_EXCHANGE_refresh_melt (exchange,
                                                          blob_size,
                                                          blob,
@@ -589,7 +610,8 @@ deposit_cb (void *cls,
 
 /**
  * Function called upon completion of our /reserve/withdraw request.
- * This is merely the function which spends withdrawn coins
+ * This is merely the function which spends withdrawn coins. For each
+ * spent coin, ti either refresh it or re-withdraw it.
  *
  * @param cls closure with the interpreter state
  * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful status request
@@ -613,7 +635,7 @@ reserve_withdraw_cb (void *cls,
     fail ("At least one coin has not correctly been withdrawn\n");
     return;
   }
-  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "%d-th coin withdrawn\n",
               coin_index);
   coins[coin_index].sig.rsa_signature =
@@ -646,18 +668,20 @@ reserve_withdraw_cb (void *cls,
     if (GNUNET_YES == eval_probability (REFRESH_PROBABILITY)
         && GNUNET_NO == refreshed_once)
     {
+      /**
+       * Always spending 1 out of 8 KUDOS. To be improved by randomly
+       * picking the spent amount 
+       */
       struct TALER_Amount one;
       TALER_amount_get_zero (currency, &one);
       one.value = 1;
 
-      /**
-       * If the coin is going to be refreshed, only 1 unit
-       * of currency will be spent, since 4 units are going
-       * to be refreshed
-       */
       TALER_amount_subtract (&amount,
                              &one,
                              &coins[coin_index].pk->fee_deposit);
+      TALER_amount_subtract (&coins[coin_index].left,
+                             &coins[coin_index].pk->value,
+                             &one);
       coins[coin_index].refresh = GNUNET_YES;
       refreshed_once = GNUNET_YES;
     }
@@ -826,6 +850,7 @@ benchmark_run (void *cls)
                                         &reserve_pub.eddsa_pub);
 
     reserves[i].aih = TALER_EXCHANGE_admin_add_incoming (exchange,
+                                                         "http://localhost:18080/",
                                                          &reserve_pub,
                                                          &reserve_amount,
                                                          execution_date,
@@ -837,6 +862,9 @@ benchmark_run (void *cls)
     json_decref (transfer_details);
   }
   json_decref (sender_details);
+  sender_details = NULL;
+  transfer_details = NULL;
+
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
               "benchmark_run() returns\n");
 }
@@ -847,7 +875,7 @@ benchmark_run (void *cls)
  * since that is the only amount refreshed so far by the benchmark
  *
  * @param NULL-terminated array of value.fraction pairs
- * @return GNUNET_OK if the array is correctly built, GNUNET_SYSERR
+ * @return #GNUNET_OK if the array is correctly built, #GNUNET_SYSERR
  * otherwise
  */
 static unsigned int
@@ -994,7 +1022,6 @@ do_shutdown (void *cls)
 
   GNUNET_free_non_null (reserves);
   GNUNET_free_non_null (coins);
-  GNUNET_free_non_null (spent_coins);
   GNUNET_free_non_null (currency);
 
   if (NULL != exchange)
@@ -1085,10 +1112,6 @@ run (void *cls)
                                      NULL);
 
   GNUNET_CONFIGURATION_destroy (cfg);
-  GNUNET_array_append (spent_coins,
-                       spent_coins_size,
-                       1);
-  spent_coins_size++;
   reserves = NULL;
   coins = NULL;
   ctx = GNUNET_CURL_init (&GNUNET_CURL_gnunet_scheduler_reschedule,
diff --git a/src/exchange-lib/exchange_api_admin.c b/src/exchange-lib/exchange_api_admin.c
index 0452a9546..0d3129186 100644
--- a/src/exchange-lib/exchange_api_admin.c
+++ b/src/exchange-lib/exchange_api_admin.c
@@ -141,6 +141,7 @@ handle_admin_add_incoming_finished (void *cls,
  * to the operators of the exchange.
  *
  * @param exchange the exchange handle; the exchange must be ready to operate
+ * @param admin_url URL of the administrative interface of the exchange
  * @param reserve_pub public key of the reserve
  * @param amount amount that was deposited
  * @param execution_date when did we receive the amount
@@ -156,6 +157,7 @@ handle_admin_add_incoming_finished (void *cls,
  */
 struct TALER_EXCHANGE_AdminAddIncomingHandle *
 TALER_EXCHANGE_admin_add_incoming (struct TALER_EXCHANGE_Handle *exchange,
+                                   const char *admin_url,
                                    const struct TALER_ReservePublicKeyP *reserve_pub,
                                    const struct TALER_Amount *amount,
                                    struct GNUNET_TIME_Absolute execution_date,
@@ -188,7 +190,8 @@ TALER_EXCHANGE_admin_add_incoming (struct TALER_EXCHANGE_Handle *exchange,
   aai->exchange = exchange;
   aai->cb = res_cb;
   aai->cb_cls = res_cb_cls;
-  aai->url = MAH_path_to_url (exchange, "/admin/add/incoming");
+  aai->url = MAH_path_to_url2 (admin_url,
+                               "/admin/add/incoming");
 
   eh = curl_easy_init ();
   GNUNET_assert (NULL != (aai->json_enc =
diff --git a/src/exchange-lib/exchange_api_handle.c b/src/exchange-lib/exchange_api_handle.c
index b9104869e..318fd9e6b 100644
--- a/src/exchange-lib/exchange_api_handle.c
+++ b/src/exchange-lib/exchange_api_handle.c
@@ -779,23 +779,39 @@ MAH_handle_is_ready (struct TALER_EXCHANGE_Handle *h)
 /**
  * Obtain the URL to use for an API request.
  *
- * @param h the exchange handle to query
+ * @param base_url base URL of the exchange (i.e. "http://exchange/")
  * @param path Taler API path (i.e. "/reserve/withdraw")
  * @return the full URI to use with cURL
  */
 char *
-MAH_path_to_url (struct TALER_EXCHANGE_Handle *h,
+MAH_path_to_url (struct TALER_EXCHANGE_Handle *exchange,
                  const char *path)
 {
+  return MAH_path_to_url2 (exchange->url,
+                           path);
+}
+
+
+/**
+ * Obtain the URL to use for an API request.
+ *
+ * @param base_url base URL of the exchange (i.e. "http://exchange/")
+ * @param path Taler API path (i.e. "/reserve/withdraw")
+ * @return the full URI to use with cURL
+ */
+char *
+MAH_path_to_url2 (const char *base_url,
+                  const char *path)
+{
   char *url;
 
   if ( ('/' == path[0]) &&
-       (0 < strlen (h->url)) &&
-       ('/' == h->url[strlen (h->url) - 1]) )
+       (0 < strlen (base_url)) &&
+       ('/' == base_url[strlen (base_url) - 1]) )
     path++; /* avoid generating URL with "//" from concat */
   GNUNET_asprintf (&url,
                    "%s%s",
-                   h->url,
+                   base_url,
                    path);
   return url;
 }
diff --git a/src/exchange-lib/exchange_api_handle.h b/src/exchange-lib/exchange_api_handle.h
index 2cf2166d0..6a5661508 100644
--- a/src/exchange-lib/exchange_api_handle.h
+++ b/src/exchange-lib/exchange_api_handle.h
@@ -55,5 +55,16 @@ char *
 MAH_path_to_url (struct TALER_EXCHANGE_Handle *h,
                  const char *path);
 
+/**
+ * Obtain the URL to use for an API request.
+ *
+ * @param base_url base URL of the exchange (i.e. "http://exchange/")
+ * @param path Taler API path (i.e. "/reserve/withdraw")
+ * @return the full URI to use with cURL
+ */
+char *
+MAH_path_to_url2 (const char *base_url,
+                  const char *path);
+
 
 /* end of exchange_api_handle.h */
diff --git a/src/exchange-lib/test_exchange_api.c b/src/exchange-lib/test_exchange_api.c
index 337fd297b..d0e2632e0 100644
--- a/src/exchange-lib/test_exchange_api.c
+++ b/src/exchange-lib/test_exchange_api.c
@@ -1753,6 +1753,7 @@ interpreter_run (void *cls)
     GNUNET_TIME_round_abs (&execution_date);
     cmd->details.admin_add_incoming.aih
       = TALER_EXCHANGE_admin_add_incoming (exchange,
+                                           "http://localhost:18080/",
                                            &reserve_pub,
                                            &amount,
                                            execution_date,
diff --git a/src/exchange/exchange.conf b/src/exchange/exchange.conf
index afb5b8fae..333e9a58a 100644
--- a/src/exchange/exchange.conf
+++ b/src/exchange/exchange.conf
@@ -11,6 +11,20 @@ KEYDIR = ${TALER_DATA_HOME}/exchange/live-keys/
 # the actual coin operations.
 # WIREFORMAT = test
 
+# Master public key used to sign the exchange's various keys
+# MASTER_PUBLIC_KEY = 98NJW3CQHZQGQXTY3K85K531XKPAPAVV4Q5V8PYYRR00NJGZWNVG
+
+# How to access our database
+DB = postgres
+
+# Is this is a testcase, use transient DB actions?
+# TESTRUN = YES
+
+# Where do we store the offline master private key of the exchange?
+MASTER_PRIV_FILE = ${TALER_DATA_HOME}/exchange/offline-keys/master.priv
+
+
+# Network configuration for the normal API/service HTTP server
 # serve via tcp socket (on PORT)
 SERVE = tcp
 
@@ -22,15 +36,17 @@ UNIXPATH_MODE = 660
 # HTTP port the exchange listens to
 PORT = 8081
 
-# Master public key used to sign the exchange's various keys
-# MASTER_PUBLIC_KEY = 98NJW3CQHZQGQXTY3K85K531XKPAPAVV4Q5V8PYYRR00NJGZWNVG
 
-# How to access our database
-DB = postgres
+[exchange-admin]
+# Network configuration for the /admin HTTP server
 
-# Is this is a testcase, use transient DB actions?
-# TESTRUN = YES
+# serve via tcp socket (on PORT)
+SERVE = tcp
 
-# Where do we store the offline master private key of the exchange?
-MASTER_PRIV_FILE = ${TALER_DATA_HOME}/exchange/offline-keys/master.priv
+# Unix domain socket to listen on,
+# only effective with "SERVE = unix"
+UNIXPATH = ${TALER_RUNTIME_DIR}/exchange-admin.http
+UNIXPATH_MODE = 660
 
+# HTTP port the exchange listens to
+PORT = 18080
diff --git a/src/exchange/taler-exchange-httpd.c b/src/exchange/taler-exchange-httpd.c
index ff18fb862..4b269a392 100644
--- a/src/exchange/taler-exchange-httpd.c
+++ b/src/exchange/taler-exchange-httpd.c
@@ -88,7 +88,17 @@ static unsigned int connection_timeout = 30;
 /**
  * The HTTP Daemon.
  */
-static struct MHD_Daemon *mydaemon;
+static struct MHD_Daemon *mhd;
+
+/**
+ * The HTTP Daemon for /admin-requests.
+ */
+static struct MHD_Daemon *mhd_admin;
+
+/**
+ * Do not offer /admin API.
+ */
+static int no_admin;
 
 /**
  * Port to run the daemon on.
@@ -96,16 +106,32 @@ static struct MHD_Daemon *mydaemon;
 static uint16_t serve_port;
 
 /**
+ * Port to run the admin daemon on.
+ */
+static uint16_t serve_admin_port;
+
+/**
  * Path for the unix domain-socket
  * to run the daemon on.
  */
 static char *serve_unixpath;
 
 /**
+ * Path for the unix domain-socket
+ * to run the admin daemon on.
+ */
+static char *serve_admin_unixpath;
+
+/**
  * File mode for unix-domain socket.
  */
 static mode_t unixpath_mode;
 
+/**
+ * File mode for unix-domain socket.
+ */
+static mode_t unixpath_admin_mode;
+
 
 /**
  * Function called whenever MHD is done with a request.  If the
@@ -251,14 +277,6 @@ handle_mhd_request (void *cls,
         "Only GET is allowed", 0,
         &TMH_MHD_handler_send_json_pack_error, MHD_HTTP_METHOD_NOT_ALLOWED },
 
-      /* FIXME: maybe conditionally compile these? */
-      { "/admin/add/incoming", MHD_HTTP_METHOD_POST, "application/json",
-        NULL, 0,
-        &TMH_ADMIN_handler_admin_add_incoming, MHD_HTTP_OK },
-      { "/admin/add/incoming", NULL, "text/plain",
-        "Only POST is allowed", 0,
-        &TMH_MHD_handler_send_json_pack_error, MHD_HTTP_METHOD_NOT_ALLOWED },
-
       { "/track/transfer", MHD_HTTP_METHOD_GET, "application/json",
         NULL, 0,
         &TMH_TRACKING_handler_track_transfer, MHD_HTTP_OK },
@@ -272,6 +290,74 @@ handle_mhd_request (void *cls,
         "Only POST is allowed", 0,
         &TMH_MHD_handler_send_json_pack_error, MHD_HTTP_METHOD_NOT_ALLOWED },
 
+      { NULL, NULL, NULL, NULL, 0, 0 }
+    };
+  static struct TMH_RequestHandler h404 =
+    {
+      "", NULL, "text/html",
+      "<html><title>404: not found</title></html>", 0,
+      &TMH_MHD_handler_static_response, MHD_HTTP_NOT_FOUND
+    };
+  struct TMH_RequestHandler *rh;
+  unsigned int i;
+
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "Handling request for URL '%s'\n",
+              url);
+  for (i=0;NULL != handlers[i].url;i++)
+  {
+    rh = &handlers[i];
+    if ( (0 == strcasecmp (url,
+                           rh->url)) &&
+         ( (NULL == rh->method) ||
+           (0 == strcasecmp (method,
+                             rh->method)) ) )
+      return rh->handler (rh,
+                          connection,
+                          con_cls,
+                          upload_data,
+                          upload_data_size);
+  }
+  return TMH_MHD_handler_static_response (&h404,
+                                          connection,
+                                          con_cls,
+                                          upload_data,
+                                          upload_data_size);
+}
+
+
+/**
+ * Handle incoming administrative HTTP request.
+ *
+ * @param cls closure for MHD daemon (unused)
+ * @param connection the connection
+ * @param url the requested url
+ * @param method the method (POST, GET, ...)
+ * @param version HTTP version (ignored)
+ * @param upload_data request data
+ * @param upload_data_size size of @a upload_data in bytes
+ * @param con_cls closure for request (a `struct Buffer *`)
+ * @return MHD result code
+ */
+static int
+handle_mhd_admin_request (void *cls,
+                          struct MHD_Connection *connection,
+                          const char *url,
+                          const char *method,
+                          const char *version,
+                          const char *upload_data,
+                          size_t *upload_data_size,
+                          void **con_cls)
+{
+  static struct TMH_RequestHandler handlers[] =
+    {
+      { "/admin/add/incoming", MHD_HTTP_METHOD_POST, "application/json",
+        NULL, 0,
+        &TMH_ADMIN_handler_admin_add_incoming, MHD_HTTP_OK },
+      { "/admin/add/incoming", NULL, "text/plain",
+        "Only POST is allowed", 0,
+        &TMH_MHD_handler_send_json_pack_error, MHD_HTTP_METHOD_NOT_ALLOWED },
+
 #if HAVE_DEVELOPER
       /* Client crypto-interoperability test functions */
       { "/test", MHD_HTTP_METHOD_POST, "application/json",
@@ -375,6 +461,123 @@ handle_mhd_request (void *cls,
 
 
 /**
+ * Parse the configuration to determine on which port
+ * or UNIX domain path we should run an HTTP service.
+ *
+ * @param type section of the configuration to parse ("exchange" or "exchange-admin")
+ * @param[out] port set to the port number, or 0 for none
+ * @param[out] unix_path set to the UNIX path, or NULL for none
+ * @param[out] unix_mode set to the mode to be used for @a unix_path
+ * @return #GNUNET_OK on success
+ */
+static int
+parse_port_config (const char *section,
+                   uint16_t *rport,
+                   char **unix_path,
+                   mode_t *unix_mode)
+{
+  const char *choices[] = {"tcp", "unix"};
+  const char *serve_type;
+  unsigned long long port;
+
+  if (GNUNET_OK !=
+      GNUNET_CONFIGURATION_get_value_choice (cfg,
+                                             section,
+                                             "serve",
+                                             choices,
+                                             &serve_type))
+  {
+    GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+                               section,
+                               "serve",
+                               "serve type required");
+    return GNUNET_SYSERR;
+  }
+
+  if (0 == strcmp (serve_type, "tcp"))
+  {
+    if (GNUNET_OK !=
+        GNUNET_CONFIGURATION_get_value_number (cfg,
+                                               section,
+                                               "port",
+                                               &port))
+    {
+      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+                                 section,
+                                 "port",
+                                 "port number required");
+      return GNUNET_SYSERR;
+    }
+
+    if ( (0 == port) ||
+         (port > UINT16_MAX) )
+    {
+      fprintf (stderr,
+               "Invalid configuration (value out of range): %llu is not a valid port\n",
+               port);
+      return GNUNET_SYSERR;
+    }
+    *rport = (uint16_t) port;
+    *unix_path = NULL;
+    return GNUNET_OK;
+  }
+  if (0 == strcmp (serve_type, "unix"))
+  {
+    struct sockaddr_un s_un;
+    char *modestring;
+
+    if (GNUNET_OK !=
+        GNUNET_CONFIGURATION_get_value_filename (cfg,
+                                                 section,
+                                                 "unixpath",
+                                                 unix_path))
+    {
+      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+                                 section,
+                                 "unixpath",
+                                 "unixpath required");
+      return GNUNET_SYSERR;
+    }
+    if (strlen (*unix_path) >= sizeof (s_un.sun_path))
+    {
+      fprintf (stderr,
+               "Invalid configuration: unix path too long\n");
+      return GNUNET_SYSERR;
+    }
+
+    if (GNUNET_OK !=
+        GNUNET_CONFIGURATION_get_value_string (cfg,
+                                               section,
+                                               "unixpath_mode",
+                                               &modestring))
+    {
+      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+                                 section,
+                                 "unixpath_mode",
+                                 "unixpath_mode required");
+      return GNUNET_SYSERR;
+    }
+    errno = 0;
+    *unix_mode = (mode_t) strtoul (modestring, NULL, 8);
+    if (0 != errno)
+    {
+      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+                                 section,
+                                 "unixpath_mode",
+                                 "unixpath_mode required");
+      GNUNET_free (modestring);
+      return GNUNET_SYSERR;
+    }
+    GNUNET_free (modestring);
+    return GNUNET_OK;
+  }
+  /* not reached */
+  GNUNET_assert (0);
+  return GNUNET_SYSERR;
+}
+
+
+/**
  * Load configuration parameters for the exchange
  * server into the corresponding global variables.
  *
@@ -384,7 +587,6 @@ handle_mhd_request (void *cls,
 static int
 exchange_serve_process_config ()
 {
-  unsigned long long port;
   char *TMH_master_public_key_str;
 
   if (GNUNET_OK !=
@@ -464,115 +666,24 @@ exchange_serve_process_config ()
     TMH_plugin->create_tables (TMH_plugin->cls);
   }
 
+  if (GNUNET_OK !=
+      parse_port_config ("exchange",
+                         &serve_port,
+                         &serve_unixpath,
+                         &unixpath_mode))
   {
-    const char *choices[] = {"tcp", "unix"};
-    const char *serve_type;
-
-    if (GNUNET_OK !=
-        GNUNET_CONFIGURATION_get_value_choice (cfg,
-                                               "exchange",
-                                               "serve",
-                                               choices,
-                                               &serve_type))
-    {
-      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
-                                 "exchange",
-                                 "serve",
-                                 "serve type required");
-      TMH_VALIDATION_done ();
-      return GNUNET_SYSERR;
-    }
-
-    if (0 == strcmp (serve_type, "tcp"))
-    {
-      if (GNUNET_OK !=
-          GNUNET_CONFIGURATION_get_value_number (cfg,
-                                                 "exchange",
-                                                 "port",
-                                                 &port))
-      {
-        GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
-                                   "exchange",
-                                   "port",
-                                   "port number required");
-        TMH_VALIDATION_done ();
-        return GNUNET_SYSERR;
-      }
-
-      if ( (0 == port) ||
-           (port > UINT16_MAX) )
-      {
-        fprintf (stderr,
-                 "Invalid configuration (value out of range): %llu is not a valid port\n",
-                 port);
-        TMH_VALIDATION_done ();
-        return GNUNET_SYSERR;
-      }
-      serve_port = (uint16_t) port;
-    }
-    else if (0 == strcmp (serve_type, "unix"))
-    {
-      struct sockaddr_un s_un;
-      char *modestring;
-
-      if (GNUNET_OK !=
-          GNUNET_CONFIGURATION_get_value_filename (cfg,
-                                                   "exchange",
-                                                   "unixpath",
-                                                   &serve_unixpath))
-      {
-        GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
-                                   "exchange",
-                                   "unixpath",
-                                   "unixpath required");
-        TMH_VALIDATION_done ();
-        return GNUNET_SYSERR;
-      }
-
-      if (strlen (serve_unixpath) >= sizeof (s_un.sun_path))
-      {
-        fprintf (stderr,
-                 "Invalid configuration: unix path too long\n");
-        TMH_VALIDATION_done ();
-        return GNUNET_SYSERR;
-      }
-
-      if (GNUNET_OK !=
-          GNUNET_CONFIGURATION_get_value_string (cfg,
-                                                 "exchange",
-                                                 "unixpath_mode",
-                                                 &modestring))
-      {
-        GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
-                                   "exchange",
-                                   "unixpath_mode",
-                                   "unixpath_mode required");
-        TMH_VALIDATION_done ();
-        return GNUNET_SYSERR;
-      }
-      errno = 0;
-      unixpath_mode = (mode_t) strtoul (modestring, NULL, 8);
-      if (0 != errno)
-      {
-        GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
-                                   "exchange",
-                                   "unixpath_mode",
-                                   "unixpath_mode required");
-        TMH_VALIDATION_done ();
-        GNUNET_free (modestring);
-        return GNUNET_SYSERR;
-      }
-      GNUNET_free (modestring);
-
-    }
-    else
-    {
-      // not reached
-      GNUNET_assert (0);
-    }
+    TMH_VALIDATION_done ();
+    return GNUNET_SYSERR;
+  }
+  if (GNUNET_OK !=
+      parse_port_config ("exchange-admin",
+                         &serve_admin_port,
+                         &serve_admin_unixpath,
+                         &unixpath_admin_mode))
+  {
+    TMH_VALIDATION_done ();
+    return GNUNET_SYSERR;
   }
-
-
   return GNUNET_OK;
 }
 
@@ -713,6 +824,99 @@ handle_mhd_logs (void *cls,
 
 
 /**
+ * Open UNIX domain socket for listining at @a unix_path with
+ * permissions @a unix_mode.
+ *
+ * @param unix_path where to listen
+ * @param unix_mode access permissions to set
+ * @return -1 on error, otherwise the listen socket
+ */
+static int
+open_unix_path (const char *unix_path,
+                mode_t unix_mode)
+{
+  struct GNUNET_NETWORK_Handle *nh;
+  struct sockaddr_un *un;
+  int fd;
+
+  if (sizeof (un->sun_path) <= strlen (unix_path))
+  {
+    fprintf (stderr,
+             "unixpath `%s' too long\n",
+             unix_path);
+    return -1;
+  }
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "Creating listen socket '%s' with mode %o\n",
+              unix_path,
+              unix_mode);
+
+  if (GNUNET_OK !=
+      GNUNET_DISK_directory_create_for_file (unix_path))
+  {
+    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
+                              "mkdir",
+                              unix_path);
+  }
+
+  un = GNUNET_new (struct sockaddr_un);
+  un->sun_family = AF_UNIX;
+  strncpy (un->sun_path,
+           unix_path,
+           sizeof (un->sun_path) - 1);
+  GNUNET_NETWORK_unix_precheck (un);
+
+  if (NULL == (nh = GNUNET_NETWORK_socket_create (AF_UNIX,
+                                                  SOCK_STREAM,
+                                                  0)))
+  {
+    fprintf (stderr,
+             "create failed for AF_UNIX\n");
+    GNUNET_free (un);
+    return -1;
+  }
+  if (GNUNET_OK !=
+      GNUNET_NETWORK_socket_bind (nh,
+                                  (void *) un,
+                                  sizeof (struct sockaddr_un)))
+  {
+    fprintf (stderr,
+             "bind failed for AF_UNIX\n");
+    GNUNET_free (un);
+    GNUNET_NETWORK_socket_close (nh);
+    return -1;
+  }
+  GNUNET_free (un);
+  if (GNUNET_OK !=
+      GNUNET_NETWORK_socket_listen (nh,
+                                    UNIX_BACKLOG))
+  {
+    fprintf (stderr,
+             "listen failed for AF_UNIX\n");
+    GNUNET_NETWORK_socket_close (nh);
+    return -1;
+  }
+
+  if (0 != chmod (serve_unixpath,
+                  unix_mode))
+  {
+    fprintf (stderr,
+             "chmod failed: %s\n",
+             strerror (errno));
+    GNUNET_NETWORK_socket_close (nh);
+    return -1;
+  }
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "set socket '%s' to mode %o\n",
+              unix_path,
+              unix_mode);
+  fd = GNUNET_NETWORK_get_fd (nh);
+  GNUNET_NETWORK_socket_free_memory_only_ (nh);
+  return fd;
+}
+
+
+/**
  * The main function of the taler-exchange-httpd server ("the exchange").
  *
  * @param argc number of arguments from the command line
@@ -729,6 +933,9 @@ main (int argc,
      "force HTTP connections to be closed after each request", 0,
      &GNUNET_GETOPT_set_one, &TMH_exchange_connection_close},
     GNUNET_GETOPT_OPTION_CFG_FILE (&cfgfile),
+    {'D', "disable-admin", NULL,
+     "do not run the /admin-HTTP server", 0,
+     &GNUNET_GETOPT_set_one, &no_admin},
     {'t', "timeout", "SECONDS",
      "after how long do connections timeout by default (in seconds)", 1,
      &GNUNET_GETOPT_set_uint, &connection_timeout},
@@ -745,6 +952,7 @@ main (int argc,
   const char *listen_pid;
   const char *listen_fds;
   int fh = -1;
+  int fh_admin = -1;
 
   GNUNET_assert (GNUNET_OK ==
                  GNUNET_log_setup ("taler-exchange-httpd",
@@ -778,7 +986,8 @@ main (int argc,
   if ( (NULL != listen_pid) &&
        (NULL != listen_fds) &&
        (getpid() == strtol (listen_pid, NULL, 10)) &&
-       (1 == strtoul (listen_fds, NULL, 10)) /* we support only 1 socket */)
+       ( (1 == strtoul (listen_fds, NULL, 10)) ||
+         (2 == strtoul (listen_fds, NULL, 10)) ) )
   {
     int flags;
 
@@ -794,97 +1003,90 @@ main (int argc,
     if (0 != fcntl (fh, F_SETFD, flags))
       GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
                            "fcntl");
+
+    if (2 == strtoul (listen_fds, NULL, 10))
+    {
+      fh_admin = 4;
+      flags = fcntl (fh_admin, F_GETFD);
+      if ( (-1 == flags) && (EBADF == errno) )
+      {
+        fprintf (stderr,
+                 "Bad listen socket passed, ignored\n");
+        fh_admin = -1;
+      }
+      flags |= FD_CLOEXEC;
+      if (0 != fcntl (fh_admin, F_SETFD, flags))
+        GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
+                             "fcntl");
+    }
   }
 
   /* consider unix path */
   if ( (-1 == fh) &&
        (NULL != serve_unixpath) )
   {
-    struct GNUNET_NETWORK_Handle *nh;
-    struct sockaddr_un *un;
-
-    if (sizeof (un->sun_path) <= strlen (serve_unixpath))
-    {
-      fprintf (stderr, "unixpath too long\n");
-      return 1;
-    }
-
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                "Creating listen socket '%s' with mode %o\n",
-                serve_unixpath,
-                unixpath_mode);
-
-    if (GNUNET_OK !=
-        GNUNET_DISK_directory_create_for_file (serve_unixpath))
-    {
-      GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
-                                "mkdir",
-                                serve_unixpath);
-    }
-
-    un = GNUNET_new (struct sockaddr_un);
-    un->sun_family = AF_UNIX;
-    strncpy (un->sun_path,
-             serve_unixpath,
-             sizeof (un->sun_path) - 1);
-
-    GNUNET_NETWORK_unix_precheck (un);
-
-    if (NULL == (nh = GNUNET_NETWORK_socket_create (AF_UNIX, SOCK_STREAM, 0)))
-    {
-      fprintf (stderr,
-               "create failed for AF_UNIX\n");
+    fh = open_unix_path (serve_unixpath,
+                         unixpath_mode);
+    if (-1 == fh)
       return 1;
-    }
-    if (GNUNET_OK != GNUNET_NETWORK_socket_bind (nh, (void *) un, sizeof (struct sockaddr_un)))
-    {
-      fprintf (stderr,
-               "bind failed for AF_UNIX\n");
-      return 1;
-    }
-    if (GNUNET_OK != GNUNET_NETWORK_socket_listen (nh, UNIX_BACKLOG))
-    {
-      fprintf (stderr,
-               "listen failed for AF_UNIX\n");
-      return 1;
-    }
-
-    fh = GNUNET_NETWORK_get_fd (nh);
-
-    if (0 != chmod (serve_unixpath, unixpath_mode))
+  }
+  if ( (-1 == fh_admin) &&
+       (0 == no_admin) &&
+       (NULL != serve_admin_unixpath) )
+  {
+    fh_admin = open_unix_path (serve_admin_unixpath,
+                               unixpath_admin_mode);
+    if (-1 == fh_admin)
     {
-      fprintf (stderr,
-               "chmod failed: %s\n",
-               strerror (errno));
+      GNUNET_break (0 == close (fh));
       return 1;
     }
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                "set socket '%s' to mode %o\n",
-                serve_unixpath,
-                unixpath_mode);
-    GNUNET_NETWORK_socket_free_memory_only_ (nh);
   }
 
-
-  mydaemon = MHD_start_daemon (MHD_USE_SELECT_INTERNALLY | MHD_USE_PIPE_FOR_SHUTDOWN | MHD_USE_DEBUG,
-                               (-1 == fh) ? serve_port : 0,
-                               NULL, NULL,
-                               &handle_mhd_request, NULL,
-                               MHD_OPTION_LISTEN_SOCKET, fh,
-                               MHD_OPTION_EXTERNAL_LOGGER, &handle_mhd_logs, NULL,
-                               MHD_OPTION_NOTIFY_COMPLETED, &handle_mhd_completion_callback, NULL,
-                               MHD_OPTION_CONNECTION_TIMEOUT, connection_timeout,
+  mhd
+    = MHD_start_daemon (MHD_USE_SELECT_INTERNALLY | MHD_USE_PIPE_FOR_SHUTDOWN | MHD_USE_DEBUG,
+                        (-1 == fh) ? serve_port : 0,
+                        NULL, NULL,
+                        &handle_mhd_request, NULL,
+                        MHD_OPTION_LISTEN_SOCKET, fh,
+                        MHD_OPTION_EXTERNAL_LOGGER, &handle_mhd_logs, NULL,
+                        MHD_OPTION_NOTIFY_COMPLETED, &handle_mhd_completion_callback, NULL,
+                        MHD_OPTION_CONNECTION_TIMEOUT, connection_timeout,
 #if HAVE_DEVELOPER
-                               MHD_OPTION_NOTIFY_CONNECTION, &connection_done, NULL,
+                        MHD_OPTION_NOTIFY_CONNECTION, &connection_done, NULL,
 #endif
-                               MHD_OPTION_END);
-
-  if (NULL == mydaemon)
+                        MHD_OPTION_END);
+  if (NULL == mhd)
   {
     fprintf (stderr,
              "Failed to start HTTP server.\n");
     return 1;
   }
+
+  if (0 == no_admin)
+  {
+    mhd_admin
+      = MHD_start_daemon (MHD_USE_SELECT_INTERNALLY | MHD_USE_PIPE_FOR_SHUTDOWN | MHD_USE_DEBUG,
+                          (-1 == fh) ? serve_admin_port : 0,
+                          NULL, NULL,
+                          &handle_mhd_admin_request, NULL,
+                          MHD_OPTION_LISTEN_SOCKET, fh_admin,
+                          MHD_OPTION_EXTERNAL_LOGGER, &handle_mhd_logs, NULL,
+                          MHD_OPTION_NOTIFY_COMPLETED, &handle_mhd_completion_callback, NULL,
+                          MHD_OPTION_CONNECTION_TIMEOUT, connection_timeout,
+#if HAVE_DEVELOPER
+                          MHD_OPTION_NOTIFY_CONNECTION, &connection_done, NULL,
+#endif
+                          MHD_OPTION_END);
+    if (NULL == mhd_admin)
+    {
+      fprintf (stderr,
+               "Failed to start administrative HTTP server.\n");
+      MHD_stop_daemon (mhd);
+      return 1;
+    }
+  }
+
 #if HAVE_DEVELOPER
   if (NULL != input_filename)
   {
@@ -905,15 +1107,20 @@ main (int argc,
   {
   case GNUNET_OK:
   case GNUNET_SYSERR:
-    MHD_stop_daemon (mydaemon);
+    MHD_stop_daemon (mhd);
+    if (NULL != mhd_admin)
+      MHD_stop_daemon (mhd_admin);
     break;
   case GNUNET_NO:
     {
-      MHD_socket sock = MHD_quiesce_daemon (mydaemon);
+      MHD_socket sock = MHD_quiesce_daemon (mhd);
+      MHD_socket admin_sock;
       pid_t chld;
       int flags;
 
       /* Set flags to make 'sock' inherited by child */
+      if (NULL != mhd_admin)
+        admin_sock = MHD_quiesce_daemon (mhd_admin);
       flags = fcntl (sock, F_GETFD);
       GNUNET_assert (-1 != flags);
       flags &= ~FD_CLOEXEC;
@@ -937,13 +1144,20 @@ main (int argc,
                                "dup2");
           _exit (1);
         }
+        if ( (NULL != mhd_admin) &&
+             (4 != dup2 (admin_sock, 4)) )
+        {
+          GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
+                               "dup2");
+          _exit (1);
+        }
         /* Tell the child that it is the desired recipient for FD #3 */
         GNUNET_snprintf (pids,
                          sizeof (pids),
                          "%u",
                          getpid ());
         setenv ("LISTEN_PID", pids, 1);
-        setenv ("LISTEN_FDS", "1", 1);
+        setenv ("LISTEN_FDS", (NULL != mhd_admin) ? "2" : "1", 1);
         /* Finally, exec the (presumably) more recent exchange binary */
         execvp ("taler-exchange-httpd",
                 argv);
@@ -955,16 +1169,25 @@ main (int argc,
          before exiting; as the listen socket is no longer used,
          close it here */
       GNUNET_break (0 == close (sock));
-      while (0 != MHD_get_daemon_info (mydaemon,
-                                       MHD_DAEMON_INFO_CURRENT_CONNECTIONS)->num_connections)
+      if (NULL != mhd_admin)
+        GNUNET_break (0 == close (admin_sock));
+      while ( (0 != MHD_get_daemon_info (mhd,
+                                         MHD_DAEMON_INFO_CURRENT_CONNECTIONS)->num_connections) ||
+              ( (NULL != mhd_admin) &&
+                (0 != MHD_get_daemon_info (mhd_admin,
+                                           MHD_DAEMON_INFO_CURRENT_CONNECTIONS)->num_connections) ) )
         sleep (1);
       /* Now we're really done, practice clean shutdown */
-      MHD_stop_daemon (mydaemon);
+      MHD_stop_daemon (mhd);
+      if (NULL != mhd_admin)
+        MHD_stop_daemon (mhd_admin);
     }
     break;
   default:
     GNUNET_break (0);
-    MHD_stop_daemon (mydaemon);
+    MHD_stop_daemon (mhd);
+    if (NULL != mhd_admin)
+      MHD_stop_daemon (mhd_admin);
     break;
   }
   TALER_EXCHANGEDB_plugin_unload (TMH_plugin);
diff --git a/src/include/Makefile.am b/src/include/Makefile.am
index d01852666..dfecf4694 100644
--- a/src/include/Makefile.am
+++ b/src/include/Makefile.am
@@ -15,6 +15,7 @@ talerinclude_HEADERS = \
   taler_amount_lib.h \
   taler_bank_service.h \
   taler_crypto_lib.h \
+  taler_error_codes.h \
   taler_exchange_service.h \
   taler_exchangedb_lib.h \
   taler_exchangedb_plugin.h \
diff --git a/src/include/taler_error_codes.h b/src/include/taler_error_codes.h
new file mode 100644
index 000000000..d58fc2e16
--- /dev/null
+++ b/src/include/taler_error_codes.h
@@ -0,0 +1,45 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2016 Inria
+
+  TALER is free software; you can redistribute it and/or modify it under the
+  terms of the GNU General Public License as published by the Free Software
+  Foundation; either version 3, or (at your option) any later version.
+
+  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+  A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License along with
+  TALER; see the file COPYING.  If not, If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file taler_error_codes.h
+ * @brief error codes returned by GNU Taler
+ *
+ * This file should defines constants for error codes returned
+ * in Taler APIs.  We use codes above 1000 to avoid any
+ * confusing with HTTP status codes.  All constants have the
+ * shared prefix "TALER_EC_" to indicate that they are error
+ * codes.
+ */
+#ifndef TALER_ERROR_CODES_H
+#define TALER_ERROR_CODES_H
+
+/**
+ * Enumeration with all possible Taler error codes.
+ */
+enum TALER_ErrorCode
+{
+
+  /**
+   * Special code to indicate no error.
+   */
+  TALER_EC_NONE = 0
+
+
+
+};
+
+
+#endif
diff --git a/src/include/taler_exchange_service.h b/src/include/taler_exchange_service.h
index ecfbc7253..4e8b0b375 100644
--- a/src/include/taler_exchange_service.h
+++ b/src/include/taler_exchange_service.h
@@ -1059,6 +1059,7 @@ typedef void
  * to the operators of the exchange.
  *
  * @param exchange the exchange handle; the exchange must be ready to operate
+ * @param admin_url URL of the administrative interface of the exchange
  * @param reserve_pub public key of the reserve
  * @param amount amount that was deposited
  * @param execution_date when did we receive the amount
@@ -1074,6 +1075,7 @@ typedef void
  */
 struct TALER_EXCHANGE_AdminAddIncomingHandle *
 TALER_EXCHANGE_admin_add_incoming (struct TALER_EXCHANGE_Handle *exchange,
+                                   const char *admin_url,
                                    const struct TALER_ReservePublicKeyP *reserve_pub,
                                    const struct TALER_Amount *amount,
                                    struct GNUNET_TIME_Absolute execution_date,
diff --git a/src/include/taler_signatures.h b/src/include/taler_signatures.h
index a58d21738..3fbfc0ab3 100644
--- a/src/include/taler_signatures.h
+++ b/src/include/taler_signatures.h
@@ -24,7 +24,6 @@
  * to know to implement Taler clients (wallets or merchants or
  * auditor) that need to produce or verify Taler signatures.
  */
-
 #ifndef TALER_SIGNATURES_H
 #define TALER_SIGNATURES_H