diff --git a/src/include/taler_exchange_service.h b/src/include/taler_exchange_service.h
index eb1452561..972b94aa1 100644
--- a/src/include/taler_exchange_service.h
+++ b/src/include/taler_exchange_service.h
@@ -1685,6 +1685,7 @@ TALER_EXCHANGE_track_transaction_cancel (struct
  * Convenience function.  Verifies a coin's transaction history as
  * returned by the exchange.
  *
+ * @param dk fee structure for the coin, NULL to skip verifying fees
  * @param currency expected currency for the coin
  * @param coin_pub public key of the coin
  * @param history history of the coin in json encoding
@@ -1692,7 +1693,9 @@ TALER_EXCHANGE_track_transaction_cancel (struct
  * @return #GNUNET_OK if @a history is valid, #GNUNET_SYSERR if not
  */
 int
-TALER_EXCHANGE_verify_coin_history (const char *currency,
+TALER_EXCHANGE_verify_coin_history (const struct
+                                    TALER_EXCHANGE_DenomPublicKey *dk,
+                                    const char *currency,
                                     const struct
                                     TALER_CoinSpendPublicKeyP *coin_pub,
                                     json_t *history,
diff --git a/src/lib/exchange_api_common.c b/src/lib/exchange_api_common.c
index c7e76985d..3860a6613 100644
--- a/src/lib/exchange_api_common.c
+++ b/src/lib/exchange_api_common.c
@@ -29,6 +29,7 @@
 /**
  * Verify a coins transaction history as returned by the exchange.
  *
+ * @param dk fee structure for the coin, NULL to skip verifying fees
  * @param currency expected currency for the coin
  * @param coin_pub public key of the coin
  * @param history history of the coin in json encoding
@@ -36,7 +37,9 @@
  * @return #GNUNET_OK if @a history is valid, #GNUNET_SYSERR if not
  */
 int
-TALER_EXCHANGE_verify_coin_history (const char *currency,
+TALER_EXCHANGE_verify_coin_history (const struct
+                                    TALER_EXCHANGE_DenomPublicKey *dk,
+                                    const char *currency,
                                     const struct
                                     TALER_CoinSpendPublicKeyP *coin_pub,
                                     json_t *history,
diff --git a/src/lib/exchange_api_deposit.c b/src/lib/exchange_api_deposit.c
index 69584ee24..23ec8a3bd 100644
--- a/src/lib/exchange_api_deposit.c
+++ b/src/lib/exchange_api_deposit.c
@@ -101,9 +101,10 @@ struct TALER_EXCHANGE_DepositHandle
   struct TALER_Amount amount_with_fee;
 
   /**
-   * Total value of the coin being transacted with.
+   * @brief Public information about the coin's denomination key.
+   * Note that the "key" field itself has been zero'ed out.
    */
-  struct TALER_Amount coin_value;
+  struct TALER_EXCHANGE_DenomPublicKey dki;
 
   /**
    * Chance that we will inform the auditor about the deposit
@@ -250,7 +251,8 @@ verify_deposit_signature_forbidden (const struct
   history = json_object_get (json,
                              "history");
   if (GNUNET_OK !=
-      TALER_EXCHANGE_verify_coin_history (dh->coin_value.currency,
+      TALER_EXCHANGE_verify_coin_history (&dh->dki,
+                                          dh->dki.value.currency,
                                           &dh->depconf.coin_pub,
                                           history,
                                           &total))
@@ -269,7 +271,7 @@ verify_deposit_signature_forbidden (const struct
   }
 
   if (0 >= TALER_amount_cmp (&total,
-                             &dh->coin_value))
+                             &dh->dki.value))
   {
     /* transaction should have still fit */
     GNUNET_break (0);
@@ -604,7 +606,9 @@ TALER_EXCHANGE_deposit (struct TALER_EXCHANGE_Handle *exchange,
   dh->depconf.coin_pub = *coin_pub;
   dh->depconf.merchant = *merchant_pub;
   dh->amount_with_fee = *amount;
-  dh->coin_value = dki->value;
+  dh->dki = *dki;
+  dh->dki.key.rsa_public_key = NULL; /* lifetime not warranted, so better
+                                        not copy the pointer */
 
   eh = TEL_curl_easy_get (dh->url);
   if (GNUNET_OK !=
diff --git a/src/lib/exchange_api_payback.c b/src/lib/exchange_api_payback.c
index f9df27e7a..b2ef9f204 100644
--- a/src/lib/exchange_api_payback.c
+++ b/src/lib/exchange_api_payback.c
@@ -237,7 +237,8 @@ handle_payback_finished (void *cls,
       history = json_object_get (j,
                                  "history");
       if (GNUNET_OK !=
-          TALER_EXCHANGE_verify_coin_history (dki->fee_deposit.currency,
+          TALER_EXCHANGE_verify_coin_history (dki,
+                                              dki->fee_deposit.currency,
                                               &ph->coin_pub,
                                               history,
                                               &total))
@@ -366,8 +367,7 @@ TALER_EXCHANGE_payback (struct TALER_EXCHANGE_Handle *exchange,
   ph->coin_pub = pr.coin_pub;
   ph->exchange = exchange;
   ph->pk = *pk;
-  ph->pk.key.rsa_public_key = GNUNET_CRYPTO_rsa_public_key_dup (
-    pk->key.rsa_public_key);
+  ph->pk.key.rsa_public_key = NULL; /* zero out, as lifetime cannot be warranted */
   ph->cb = payback_cb;
   ph->cb_cls = payback_cb_cls;
   ph->url = TEAH_path_to_url (exchange, "/payback");
@@ -382,7 +382,6 @@ TALER_EXCHANGE_payback (struct TALER_EXCHANGE_Handle *exchange,
     curl_easy_cleanup (eh);
     json_decref (payback_obj);
     GNUNET_free (ph->url);
-    GNUNET_CRYPTO_rsa_public_key_free (ph->pk.key.rsa_public_key);
     GNUNET_free (ph);
     return NULL;
   }
@@ -416,7 +415,6 @@ TALER_EXCHANGE_payback_cancel (struct TALER_EXCHANGE_PaybackHandle *ph)
   }
   GNUNET_free (ph->url);
   TALER_curl_easy_post_finished (&ph->ctx);
-  GNUNET_CRYPTO_rsa_public_key_free (ph->pk.key.rsa_public_key);
   GNUNET_free (ph);
 }
 
diff --git a/src/lib/exchange_api_refresh.c b/src/lib/exchange_api_refresh.c
index a75baec86..cf852d37f 100644
--- a/src/lib/exchange_api_refresh.c
+++ b/src/lib/exchange_api_refresh.c
@@ -864,6 +864,11 @@ struct TALER_EXCHANGE_RefreshMeltHandle
    * Actual information about the melt operation.
    */
   struct MeltData *md;
+
+  /**
+   * @brief Public information about the coin's denomination key
+   */
+  struct TALER_EXCHANGE_DenomPublicKey dki;
 };
 
 
@@ -1000,7 +1005,8 @@ verify_refresh_melt_signature_conflict (struct
   history = json_object_get (json,
                              "history");
   if (GNUNET_OK !=
-      TALER_EXCHANGE_verify_coin_history (original_value.currency,
+      TALER_EXCHANGE_verify_coin_history (&rmh->dki,
+                                          original_value.currency,
                                           &coin_pub,
                                           history,
                                           &total))
@@ -1153,6 +1159,8 @@ TALER_EXCHANGE_refresh_melt (struct TALER_EXCHANGE_Handle *exchange,
                              TALER_EXCHANGE_RefreshMeltCallback melt_cb,
                              void *melt_cb_cls)
 {
+  const struct TALER_EXCHANGE_Keys *key_state;
+  const struct TALER_EXCHANGE_DenomPublicKey *dki;
   json_t *melt_obj;
   struct TALER_EXCHANGE_RefreshMeltHandle *rmh;
   CURL *eh;
@@ -1208,10 +1216,16 @@ TALER_EXCHANGE_refresh_melt (struct TALER_EXCHANGE_Handle *exchange,
     free_melt_data (md);
     return NULL;
   }
+  key_state = TALER_EXCHANGE_get_keys (exchange);
+  dki = TALER_EXCHANGE_get_denomination_key (key_state,
+                                             &md->melted_coin.pub_key);
 
   /* and now we can at last begin the actual request handling */
   rmh = GNUNET_new (struct TALER_EXCHANGE_RefreshMeltHandle);
   rmh->exchange = exchange;
+  rmh->dki = *dki;
+  rmh->dki.key.rsa_public_key = NULL; /* lifetime not warranted, so better
+                                         not copy the pointer */
   rmh->melt_cb = melt_cb;
   rmh->melt_cb_cls = melt_cb_cls;
   rmh->md = md;