major API refactoring, adding planchet generation and coin extraction APIs to the Taler crypto library, thereby simplifying code in withdraw, refresh, tipping, payback and testcases; slight API incompatibilities to previous versions are introduced

4 files changed, 97 insertions, 164 deletions

diff --git a/src/exchange-lib/exchange_api_payback.c b/src/exchange-lib/exchange_api_payback.c
index 40b713857..ec0cda150 100644
--- a/src/exchange-lib/exchange_api_payback.c
+++ b/src/exchange-lib/exchange_api_payback.c
@@ -260,8 +260,7 @@ handle_payback_finished (void *cls,
  * @param exchange the exchange handle; the exchange must be ready to operate
  * @param pk kind of coin to pay back
  * @param denom_sig signature over the coin by the exchange using @a pk
- * @param coin_priv the coin's private key,
- * @param blinding_key where to fetch the coin's blinding key
+ * @param ps secret internals of the original planchet
  * @param payback_cb the callback to call when the final result for this request is available
  * @param payback_cb_cls closure for @a payback_cb
  * @return NULL
@@ -272,8 +271,7 @@ struct TALER_EXCHANGE_PaybackHandle *
 TALER_EXCHANGE_payback (struct TALER_EXCHANGE_Handle *exchange,
                         const struct TALER_EXCHANGE_DenomPublicKey *pk,
                         const struct TALER_DenominationSignature *denom_sig,
-                        const struct TALER_CoinSpendPrivateKeyP *coin_priv,
-                        const struct TALER_DenominationBlindingKeyP *blinding_key,
+                        const struct TALER_PlanchetSecretsP *ps,
                         TALER_EXCHANGE_PaybackResultCallback payback_cb,
                         void *payback_cb_cls)
 {
@@ -288,12 +286,12 @@ TALER_EXCHANGE_payback (struct TALER_EXCHANGE_Handle *exchange,
 		 MAH_handle_is_ready (exchange));
   pr.purpose.purpose = htonl (TALER_SIGNATURE_WALLET_COIN_PAYBACK);
   pr.purpose.size = htonl (sizeof (struct TALER_PaybackRequestPS));
-  GNUNET_CRYPTO_eddsa_key_get_public (&coin_priv->eddsa_priv,
+  GNUNET_CRYPTO_eddsa_key_get_public (&ps->coin_priv.eddsa_priv,
                                       &pr.coin_pub.eddsa_pub);
   pr.h_denom_pub = pk->h_key;
-  pr.coin_blind = *blinding_key;
+  pr.coin_blind = ps->blinding_key;
   GNUNET_assert (GNUNET_OK ==
-                 GNUNET_CRYPTO_eddsa_sign (&coin_priv->eddsa_priv,
+                 GNUNET_CRYPTO_eddsa_sign (&ps->coin_priv.eddsa_priv,
                                            &pr.purpose,
                                            &coin_sig.eddsa_signature));
 
@@ -304,7 +302,7 @@ TALER_EXCHANGE_payback (struct TALER_EXCHANGE_Handle *exchange,
                            "denom_sig", GNUNET_JSON_from_rsa_signature (denom_sig->rsa_signature),
                            "coin_pub", GNUNET_JSON_from_data_auto (&pr.coin_pub),
                            "coin_sig", GNUNET_JSON_from_data_auto (&coin_sig),
-                           "coin_blind_key_secret", GNUNET_JSON_from_data_auto (blinding_key)
+                           "coin_blind_key_secret", GNUNET_JSON_from_data_auto (&ps->blinding_key)
 			  );
   if (NULL == payback_obj)
   {
diff --git a/src/exchange-lib/exchange_api_refresh.c b/src/exchange-lib/exchange_api_refresh.c
index 510b6e409..305747f63 100644
--- a/src/exchange-lib/exchange_api_refresh.c
+++ b/src/exchange-lib/exchange_api_refresh.c
@@ -236,18 +236,16 @@ free_melted_coin (struct MeltedCoin *mc)
 static void
 free_melt_data (struct MeltData *md)
 {
-  unsigned int i;
-
   free_melted_coin (&md->melted_coin);
   if (NULL != md->fresh_pks)
   {
-    for (i=0;i<md->num_fresh_coins;i++)
+    for (unsigned int i=0;i<md->num_fresh_coins;i++)
       if (NULL != md->fresh_pks[i].rsa_public_key)
         GNUNET_CRYPTO_rsa_public_key_free (md->fresh_pks[i].rsa_public_key);
     GNUNET_free (md->fresh_pks);
   }
 
-  for (i=0;i<TALER_CNC_KAPPA;i++)
+  for (unsigned int i=0;i<TALER_CNC_KAPPA;i++)
     GNUNET_free (md->fresh_coins[i]);
   /* Finally, clean up a bit...
      (NOTE: compilers might optimize this away, so this is
@@ -600,8 +598,6 @@ deserialize_melt_data (const char *buf,
 {
   struct MeltData *md;
   struct MeltDataP mdp;
-  unsigned int i;
-  unsigned int j;
   size_t off;
   int ok;
 
@@ -615,7 +611,7 @@ deserialize_melt_data (const char *buf,
   md->num_fresh_coins = ntohs (mdp.num_fresh_coins);
   md->fresh_pks = GNUNET_new_array (md->num_fresh_coins,
                                     struct TALER_DenominationPublicKey);
-  for (i=0;i<TALER_CNC_KAPPA;i++)
+  for (unsigned int i=0;i<TALER_CNC_KAPPA;i++)
     md->fresh_coins[i] = GNUNET_new_array (md->num_fresh_coins,
                                            struct TALER_PlanchetSecretsP);
   off = sizeof (struct MeltDataP);
@@ -624,14 +620,14 @@ deserialize_melt_data (const char *buf,
                                   &buf[off],
                                   buf_size - off,
                                   &ok);
-  for (i=0;(i<md->num_fresh_coins)&&(GNUNET_YES == ok);i++)
+  for (unsigned int i=0;(i<md->num_fresh_coins)&&(GNUNET_YES == ok);i++)
     off += deserialize_denomination_key (&md->fresh_pks[i],
                                          &buf[off],
                                          buf_size - off,
                                          &ok);
 
-  for (i=0;i<TALER_CNC_KAPPA;i++)
-    for(j=0;(j<md->num_fresh_coins)&&(GNUNET_YES == ok);j++)
+  for (unsigned int i=0;i<TALER_CNC_KAPPA;i++)
+    for (unsigned int j=0;(j<md->num_fresh_coins)&&(GNUNET_YES == ok);j++)
       off += deserialize_fresh_coin (&md->fresh_coins[i][j],
                                      &buf[off],
                                      buf_size - off,
@@ -704,8 +700,6 @@ TALER_EXCHANGE_refresh_prepare (const struct TALER_CoinSpendPrivateKeyP *melt_pr
 {
   struct MeltData md;
   char *buf;
-  unsigned int i;
-  unsigned int j;
   struct GNUNET_HashContext *hash_context;
   struct TALER_Amount total;
   struct TALER_CoinSpendPublicKeyP coin_pub;
@@ -715,7 +709,7 @@ TALER_EXCHANGE_refresh_prepare (const struct TALER_CoinSpendPrivateKeyP *melt_pr
                                       &coin_pub.eddsa_pub);
   hash_context = GNUNET_CRYPTO_hash_context_start ();
   /* build up melt data structure */
-  for (i=0;i<TALER_CNC_KAPPA;i++)
+  for (unsigned int i=0;i<TALER_CNC_KAPPA;i++)
   {
     struct GNUNET_CRYPTO_EcdhePrivateKey *tpk;
     struct TALER_TransferPublicKeyP tp;
@@ -747,18 +741,18 @@ TALER_EXCHANGE_refresh_prepare (const struct TALER_CoinSpendPrivateKeyP *melt_pr
     = GNUNET_CRYPTO_rsa_signature_dup (melt_sig->rsa_signature);
   md.fresh_pks = GNUNET_new_array (fresh_pks_len,
                                    struct TALER_DenominationPublicKey);
-  for (i=0;i<fresh_pks_len;i++)
+  for (unsigned int i=0;i<fresh_pks_len;i++)
     md.fresh_pks[i].rsa_public_key
       = GNUNET_CRYPTO_rsa_public_key_dup (fresh_pks[i].key.rsa_public_key);
-  for (i=0;i<TALER_CNC_KAPPA;i++)
+  for (unsigned int i=0;i<TALER_CNC_KAPPA;i++)
   {
     md.fresh_coins[i] = GNUNET_new_array (fresh_pks_len,
                                           struct TALER_PlanchetSecretsP);
-    for (j=0;j<fresh_pks_len;j++)
+    for (unsigned int j=0;j<fresh_pks_len;j++)
     {
       TALER_planchet_setup_refresh (&trans_sec[i],
-                              j,
-                              &md.fresh_coins[i][j]);
+                                    j,
+                                    &md.fresh_coins[i][j]);
     }
   }
 
@@ -766,7 +760,7 @@ TALER_EXCHANGE_refresh_prepare (const struct TALER_CoinSpendPrivateKeyP *melt_pr
   GNUNET_assert (GNUNET_OK ==
 		 TALER_amount_get_zero (melt_amount->currency,
 					&total));
-  for (j=0;j<fresh_pks_len;j++)
+  for (unsigned int j=0;j<fresh_pks_len;j++)
   {
     if ( (GNUNET_OK !=
 	  TALER_amount_add (&total,
@@ -795,7 +789,7 @@ TALER_EXCHANGE_refresh_prepare (const struct TALER_CoinSpendPrivateKeyP *melt_pr
 
   /* next, add all of the hashes from the denomination keys to the
      hash_context */
-  for (i=0;i<fresh_pks_len;i++)
+  for (unsigned int i=0;i<fresh_pks_len;i++)
   {
     char *buf;
     size_t buf_size;
@@ -820,28 +814,18 @@ TALER_EXCHANGE_refresh_prepare (const struct TALER_CoinSpendPrivateKeyP *melt_pr
                                      sizeof (struct TALER_AmountNBO));
 
   }
-  for (i = 0; i < TALER_CNC_KAPPA; i++)
+  for (unsigned int i = 0; i < TALER_CNC_KAPPA; i++)
   {
-    for (j = 0; j < fresh_pks_len; j++)
+    for (unsigned int j = 0; j < fresh_pks_len; j++)
     {
       const struct TALER_PlanchetSecretsP *fc; /* coin this is about */
-      struct TALER_CoinSpendPublicKeyP coin_pub;
-      struct GNUNET_HashCode coin_hash;
-      char *coin_ev; /* blinded message to be signed (in envelope) for each coin */
-      size_t coin_ev_size;
+      struct TALER_PlanchetDetail pd;
 
       fc = &md.fresh_coins[i][j];
-      GNUNET_CRYPTO_eddsa_key_get_public (&fc->coin_priv.eddsa_priv,
-                                          &coin_pub.eddsa_pub);
-      GNUNET_CRYPTO_hash (&coin_pub.eddsa_pub,
-                          sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey),
-                          &coin_hash);
-      if (GNUNET_YES !=
-          GNUNET_CRYPTO_rsa_blind (&coin_hash,
-                                   &fc->blinding_key.bks,
-                                   md.fresh_pks[j].rsa_public_key,
-                                   &coin_ev,
-                                   &coin_ev_size))
+      if (GNUNET_OK !=
+          TALER_planchet_prepare (&md.fresh_pks[j],
+                                  fc,
+                                  &pd))
       {
         GNUNET_break_op (0);
         GNUNET_CRYPTO_hash_context_abort (hash_context);
@@ -849,9 +833,9 @@ TALER_EXCHANGE_refresh_prepare (const struct TALER_CoinSpendPrivateKeyP *melt_pr
         return NULL;
       }
       GNUNET_CRYPTO_hash_context_read (hash_context,
-                                       coin_ev,
-                                       coin_ev_size);
-      GNUNET_free (coin_ev);
+                                       pd.coin_ev,
+                                       pd.coin_ev_size);
+      GNUNET_free (pd.coin_ev);
     }
   }
   GNUNET_CRYPTO_hash_context_finish (hash_context,
@@ -1294,22 +1278,12 @@ TALER_EXCHANGE_refresh_melt (struct TALER_EXCHANGE_Handle *exchange,
     for (i=0;i<md->num_fresh_coins;i++)
     {
       const struct TALER_PlanchetSecretsP *fc = &md->fresh_coins[j][i];
-      struct TALER_CoinSpendPublicKeyP coin_pub;
-      struct GNUNET_HashCode coin_hash;
-      char *coin_ev; /* blinded message to be signed (in envelope) for each coin */
-      size_t coin_ev_size;
-
-      GNUNET_CRYPTO_eddsa_key_get_public (&fc->coin_priv.eddsa_priv,
-                                          &coin_pub.eddsa_pub);
-      GNUNET_CRYPTO_hash (&coin_pub.eddsa_pub,
-                          sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey),
-                          &coin_hash);
-      if (GNUNET_YES !=
-          GNUNET_CRYPTO_rsa_blind (&coin_hash,
-                                   &fc->blinding_key.bks,
-                                   md->fresh_pks[i].rsa_public_key,
-                                   &coin_ev,
-                                   &coin_ev_size))
+      struct TALER_PlanchetDetail pd;
+
+      if (GNUNET_OK !=
+          TALER_planchet_prepare (&md->fresh_pks[i],
+                                  fc,
+                                  &pd))
       {
         /* This should have been noticed during the preparation stage. */
         GNUNET_break (0);
@@ -1322,9 +1296,9 @@ TALER_EXCHANGE_refresh_melt (struct TALER_EXCHANGE_Handle *exchange,
       }
       GNUNET_assert (0 ==
                      json_array_append_new (tmp,
-                                            GNUNET_JSON_from_data (coin_ev,
-                                                                   coin_ev_size)));
-      GNUNET_free (coin_ev);
+                                            GNUNET_JSON_from_data (pd.coin_ev,
+                                                                   pd.coin_ev_size)));
+      GNUNET_free (pd.coin_ev);
     }
     GNUNET_assert (0 ==
                    json_array_append_new (coin_evs,
@@ -1510,13 +1484,13 @@ refresh_reveal_ok (struct TALER_EXCHANGE_RefreshRevealHandle *rrh,
     struct TALER_DenominationPublicKey *pk;
     json_t *jsonai;
     struct GNUNET_CRYPTO_RsaSignature *blind_sig;
-    struct GNUNET_CRYPTO_RsaSignature *sig;
     struct TALER_CoinSpendPublicKeyP coin_pub;
     struct GNUNET_HashCode coin_hash;
     struct GNUNET_JSON_Specification spec[] = {
       GNUNET_JSON_spec_rsa_signature ("ev_sig", &blind_sig),
       GNUNET_JSON_spec_end()
     };
+    struct TALER_FreshCoin coin;
 
     fc = &rrh->md->fresh_coins[rrh->noreveal_index][i];
     pk = &rrh->md->fresh_pks[i];
@@ -1533,31 +1507,28 @@ refresh_reveal_ok (struct TALER_EXCHANGE_RefreshRevealHandle *rrh,
       return GNUNET_SYSERR;
     }
 
-    /* unblind the signature */
-    sig = GNUNET_CRYPTO_rsa_unblind (blind_sig,
-				     &fc->blinding_key.bks,
-                                     pk->rsa_public_key);
-    GNUNET_CRYPTO_rsa_signature_free (blind_sig);
-
-    /* verify the signature */
+    /* needed to verify the signature, and we didn't store it earlier,
+       hence recomputing it here... */
     GNUNET_CRYPTO_eddsa_key_get_public (&fc->coin_priv.eddsa_priv,
                                         &coin_pub.eddsa_pub);
     GNUNET_CRYPTO_hash (&coin_pub.eddsa_pub,
                         sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey),
                         &coin_hash);
-
     if (GNUNET_OK !=
-        GNUNET_CRYPTO_rsa_verify (&coin_hash,
-                                  sig,
-                                  pk->rsa_public_key))
+        TALER_planchet_to_coin (pk,
+                                blind_sig,
+                                fc,
+                                &coin_hash,
+                                &coin))
     {
       GNUNET_break_op (0);
-      GNUNET_CRYPTO_rsa_signature_free (sig);
+      GNUNET_CRYPTO_rsa_signature_free (blind_sig);
       GNUNET_JSON_parse_free (outer_spec);
       return GNUNET_SYSERR;
     }
-    coin_privs[i] = fc->coin_priv;
-    sigs[i].rsa_signature = sig;
+    GNUNET_CRYPTO_rsa_signature_free (blind_sig);
+    coin_privs[i] = coin.coin_priv;
+    sigs[i] = coin.sig;
   }
   GNUNET_JSON_parse_free (outer_spec);
   return GNUNET_OK;
diff --git a/src/exchange-lib/exchange_api_reserve.c b/src/exchange-lib/exchange_api_reserve.c
index 22e0e3d25..ef505d87d 100644
--- a/src/exchange-lib/exchange_api_reserve.c
+++ b/src/exchange-lib/exchange_api_reserve.c
@@ -693,9 +693,9 @@ struct TALER_EXCHANGE_ReserveWithdrawHandle
   TALER_EXCHANGE_ReserveWithdrawResultCallback cb;
 
   /**
-   * Key used to blind the value.
+   * Secrets of the planchet.
    */
-  struct TALER_DenominationBlindingKeyP blinding_key;
+  struct TALER_PlanchetSecretsP ps;
 
   /**
    * Denomination key we are withdrawing.
@@ -739,8 +739,7 @@ reserve_withdraw_ok (struct TALER_EXCHANGE_ReserveWithdrawHandle *wsh,
                      const json_t *json)
 {
   struct GNUNET_CRYPTO_RsaSignature *blind_sig;
-  struct GNUNET_CRYPTO_RsaSignature *sig;
-  struct TALER_DenominationSignature dsig;
+  struct TALER_FreshCoin fc;
   struct GNUNET_JSON_Specification spec[] = {
     GNUNET_JSON_spec_rsa_signature ("ev_sig", &blind_sig),
     GNUNET_JSON_spec_end()
@@ -754,29 +753,28 @@ reserve_withdraw_ok (struct TALER_EXCHANGE_ReserveWithdrawHandle *wsh,
     GNUNET_break_op (0);
     return GNUNET_SYSERR;
   }
-  sig = GNUNET_CRYPTO_rsa_unblind (blind_sig,
-                                   &wsh->blinding_key.bks,
-                                   wsh->pk->key.rsa_public_key);
-  GNUNET_CRYPTO_rsa_signature_free (blind_sig);
   if (GNUNET_OK !=
-      GNUNET_CRYPTO_rsa_verify (&wsh->c_hash,
-                                sig,
-                                wsh->pk->key.rsa_public_key))
+      TALER_planchet_to_coin (&wsh->pk->key,
+                              blind_sig,
+                              &wsh->ps,
+                              &wsh->c_hash,
+                              &fc))
   {
     GNUNET_break_op (0);
-    GNUNET_CRYPTO_rsa_signature_free (sig);
+    GNUNET_JSON_parse_free (spec);
     return GNUNET_SYSERR;
   }
+  GNUNET_JSON_parse_free (spec);
+
   /* signature is valid, return it to the application */
-  dsig.rsa_signature = sig;
   wsh->cb (wsh->cb_cls,
            MHD_HTTP_OK,
 	   TALER_EC_NONE,
-           &dsig,
+           &fc.sig,
            json);
   /* make sure callback isn't called again after return */
   wsh->cb = NULL;
-  GNUNET_CRYPTO_rsa_signature_free (sig);
+  GNUNET_CRYPTO_rsa_signature_free (fc.sig.rsa_signature);
   return GNUNET_OK;
 }
 
@@ -978,9 +976,7 @@ handle_reserve_withdraw_finished (void *cls,
  * @param exchange the exchange handle; the exchange must be ready to operate
  * @param pk kind of coin to create
  * @param reserve_priv private key of the reserve to withdraw from
- * @param coin_priv where to fetch the coin's private key,
- *        caller must have committed this value to disk before the call (with @a pk)
- * @param blinding_key where to fetch the coin's blinding key
+ * @param ps secrets of the planchet
  *        caller must have committed this value to disk before the call (with @a pk)
  * @param res_cb the callback to call when the final result for this request is available
  * @param res_cb_cls closure for the above callback
@@ -992,44 +988,33 @@ struct TALER_EXCHANGE_ReserveWithdrawHandle *
 TALER_EXCHANGE_reserve_withdraw (struct TALER_EXCHANGE_Handle *exchange,
                                  const struct TALER_EXCHANGE_DenomPublicKey *pk,
                                  const struct TALER_ReservePrivateKeyP *reserve_priv,
-                                 const struct TALER_CoinSpendPrivateKeyP *coin_priv,
-                                 const struct TALER_DenominationBlindingKeyP *blinding_key,
+                                 const struct TALER_PlanchetSecretsP *ps,
                                  TALER_EXCHANGE_ReserveWithdrawResultCallback res_cb,
                                  void *res_cb_cls)
 {
   struct TALER_EXCHANGE_ReserveWithdrawHandle *wsh;
   struct TALER_WithdrawRequestPS req;
   struct TALER_ReserveSignatureP reserve_sig;
-  struct TALER_CoinSpendPublicKeyP coin_pub;
   struct GNUNET_CURL_Context *ctx;
   struct TALER_Amount amount_with_fee;
-  char *coin_ev;
-  size_t coin_ev_size;
   json_t *withdraw_obj;
   CURL *eh;
+  struct TALER_PlanchetDetail pd;
 
+  if (GNUNET_OK !=
+      TALER_planchet_prepare (&pk->key,
+                              ps,
+                              &pd))
+  {
+    GNUNET_break_op (0);
+    return NULL;
+  }
   wsh = GNUNET_new (struct TALER_EXCHANGE_ReserveWithdrawHandle);
   wsh->exchange = exchange;
   wsh->cb = res_cb;
   wsh->cb_cls = res_cb_cls;
   wsh->pk = pk;
-
-  GNUNET_CRYPTO_eddsa_key_get_public (&coin_priv->eddsa_priv,
-                                      &coin_pub.eddsa_pub);
-  GNUNET_CRYPTO_hash (&coin_pub.eddsa_pub,
-                      sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey),
-                      &wsh->c_hash);
-  if (GNUNET_YES !=
-      GNUNET_CRYPTO_rsa_blind (&wsh->c_hash,
-                               &blinding_key->bks,
-                               pk->key.rsa_public_key,
-                               &coin_ev,
-                               &coin_ev_size))
-  {
-    GNUNET_break_op (0);
-    GNUNET_free (wsh);
-    return NULL;
-  }
+  wsh->c_hash = pd.c_hash;
   GNUNET_CRYPTO_eddsa_key_get_public (&reserve_priv->eddsa_priv,
                                       &wsh->reserve_pub.eddsa_pub);
   req.purpose.size = htonl (sizeof (struct TALER_WithdrawRequestPS));
@@ -1042,7 +1027,7 @@ TALER_EXCHANGE_reserve_withdraw (struct TALER_EXCHANGE_Handle *exchange,
   {
     /* exchange gave us denomination keys that overflow like this!? */
     GNUNET_break_op (0);
-    GNUNET_free (coin_ev);
+    GNUNET_free (pd.coin_ev);
     GNUNET_free (wsh);
     return NULL;
   }
@@ -1050,10 +1035,9 @@ TALER_EXCHANGE_reserve_withdraw (struct TALER_EXCHANGE_Handle *exchange,
                      &amount_with_fee);
   TALER_amount_hton (&req.withdraw_fee,
                      &pk->fee_withdraw);
-  GNUNET_CRYPTO_rsa_public_key_hash (pk->key.rsa_public_key,
-                                     &req.h_denomination_pub);
-  GNUNET_CRYPTO_hash (coin_ev,
-                      coin_ev_size,
+  req.h_denomination_pub = pd.denom_pub_hash;
+  GNUNET_CRYPTO_hash (pd.coin_ev,
+                      pd.coin_ev_size,
                       &req.h_coin_envelope);
   GNUNET_assert (GNUNET_OK ==
                  GNUNET_CRYPTO_eddsa_sign (&reserve_priv->eddsa_priv,
@@ -1062,11 +1046,11 @@ TALER_EXCHANGE_reserve_withdraw (struct TALER_EXCHANGE_Handle *exchange,
   withdraw_obj = json_pack ("{s:o, s:o," /* denom_pub and coin_ev */
                             " s:o, s:o}",/* reserve_pub and reserve_sig */
                             "denom_pub", GNUNET_JSON_from_rsa_public_key (pk->key.rsa_public_key),
-                            "coin_ev", GNUNET_JSON_from_data (coin_ev,
-                                                              coin_ev_size),
+                            "coin_ev", GNUNET_JSON_from_data (pd.coin_ev,
+                                                              pd.coin_ev_size),
                             "reserve_pub", GNUNET_JSON_from_data_auto (&wsh->reserve_pub),
                             "reserve_sig", GNUNET_JSON_from_data_auto (&reserve_sig));
-  GNUNET_free (coin_ev);
+  GNUNET_free (pd.coin_ev);
   if (NULL == withdraw_obj)
   {
     GNUNET_break (0);
@@ -1074,7 +1058,7 @@ TALER_EXCHANGE_reserve_withdraw (struct TALER_EXCHANGE_Handle *exchange,
   }
 
 
-  wsh->blinding_key = *blinding_key;
+  wsh->ps = *ps;
   wsh->url = MAH_path_to_url (exchange, "/reserve/withdraw");
 
   eh = curl_easy_init ();
diff --git a/src/exchange-lib/test_exchange_api.c b/src/exchange-lib/test_exchange_api.c
index 70fb3ffdc..7c0dfa982 100644
--- a/src/exchange-lib/test_exchange_api.c
+++ b/src/exchange-lib/test_exchange_api.c
@@ -341,14 +341,9 @@ struct Command
       struct TALER_DenominationSignature sig;
 
       /**
-       * Set (by the interpreter) to the coin's private key.
+       * Private key material of the coin, set by the interpreter.
        */
-      struct TALER_CoinSpendPrivateKeyP coin_priv;
-
-      /**
-       * Blinding key used for the operation.
-       */
-      struct TALER_DenominationBlindingKeyP blinding_key;
+      struct TALER_PlanchetSecretsP ps;
 
       /**
        * Withdraw handle (while operation is running).
@@ -1984,7 +1979,7 @@ get_public_key_from_coin_command (const struct Command *coin,
   switch (coin->oc)
   {
   case OC_WITHDRAW_SIGN:
-    GNUNET_CRYPTO_eddsa_key_get_public (&coin->details.reserve_withdraw.coin_priv.eddsa_priv,
+    GNUNET_CRYPTO_eddsa_key_get_public (&coin->details.reserve_withdraw.ps.coin_priv.eddsa_priv,
                                         &coin_pub->eddsa_pub);
     break;
   case OC_REFRESH_REVEAL:
@@ -2016,7 +2011,6 @@ interpreter_run (void *cls)
   struct Command *cmd = &is->commands[is->ip];
   const struct Command *ref;
   struct TALER_ReservePublicKeyP reserve_pub;
-  struct TALER_CoinSpendPublicKeyP coin_pub;
   struct TALER_Amount amount;
   struct GNUNET_TIME_Absolute execution_date;
   json_t *sender_details;
@@ -2165,27 +2159,14 @@ interpreter_run (void *cls)
       return;
     }
 
-    /* create coin's private key */
-    {
-      struct GNUNET_CRYPTO_EddsaPrivateKey *priv;
-
-      priv = GNUNET_CRYPTO_eddsa_key_create ();
-      cmd->details.reserve_withdraw.coin_priv.eddsa_priv = *priv;
-      GNUNET_free (priv);
-    }
-    GNUNET_CRYPTO_eddsa_key_get_public (&cmd->details.reserve_withdraw.coin_priv.eddsa_priv,
-                                        &coin_pub.eddsa_pub);
-    GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_WEAK,
-				&cmd->details.reserve_withdraw.blinding_key,
-				sizeof (cmd->details.reserve_withdraw.blinding_key));
+    TALER_planchet_setup_random (&cmd->details.reserve_withdraw.ps);
     cmd->details.reserve_withdraw.wsh
       = TALER_EXCHANGE_reserve_withdraw (exchange,
-                                     cmd->details.reserve_withdraw.pk,
-                                     &ref->details.admin_add_incoming.reserve_priv,
-                                     &cmd->details.reserve_withdraw.coin_priv,
-                                     &cmd->details.reserve_withdraw.blinding_key,
-                                     &reserve_withdraw_cb,
-                                     is);
+                                         cmd->details.reserve_withdraw.pk,
+                                         &ref->details.admin_add_incoming.reserve_priv,
+                                         &cmd->details.reserve_withdraw.ps,
+                                         &reserve_withdraw_cb,
+                                         is);
     if (NULL == cmd->details.reserve_withdraw.wsh)
     {
       GNUNET_break (0);
@@ -2217,7 +2198,7 @@ interpreter_run (void *cls)
       switch (ref->oc)
       {
       case OC_WITHDRAW_SIGN:
-        coin_priv = &ref->details.reserve_withdraw.coin_priv;
+        coin_priv = &ref->details.reserve_withdraw.ps.coin_priv;
         coin_pk = ref->details.reserve_withdraw.pk;
         coin_pk_sig = &ref->details.reserve_withdraw.sig;
         break;
@@ -2376,7 +2357,7 @@ interpreter_run (void *cls)
         GNUNET_assert (NULL != ref);
         GNUNET_assert (OC_WITHDRAW_SIGN == ref->oc);
 
-        melt_priv = ref->details.reserve_withdraw.coin_priv;
+        melt_priv = ref->details.reserve_withdraw.ps.coin_priv;
         if (GNUNET_OK !=
             TALER_string_to_amount (md->amount,
                                     &melt_amount))
@@ -2478,7 +2459,7 @@ interpreter_run (void *cls)
     /* finally, use private key from withdraw sign command */
     cmd->details.refresh_link.rlh
       = TALER_EXCHANGE_refresh_link (exchange,
-                                     &ref->details.reserve_withdraw.coin_priv,
+                                     &ref->details.reserve_withdraw.ps.coin_priv,
                                      &link_cb,
                                      is);
     if (NULL == cmd->details.refresh_link.rlh)
@@ -2745,8 +2726,7 @@ interpreter_run (void *cls)
         = TALER_EXCHANGE_payback (exchange,
                                   ref->details.reserve_withdraw.pk,
                                   &ref->details.reserve_withdraw.sig,
-                                  &ref->details.reserve_withdraw.coin_priv,
-                                  &ref->details.reserve_withdraw.blinding_key,
+                                  &ref->details.reserve_withdraw.ps,
                                   &payback_cb,
                                   is);
       return;