[taler-exchange] 01/02: -eliminate redundant hash operation on link signatures

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grothoff pushed a commit to branch master
in repository exchange.

commit f6ecb6c895879ee4b5db3061593feaad3456d1c8
Author: Christian Grothoff <christian@grothoff.org>
AuthorDate: Sat Dec 25 15:39:01 2021 +0100

    -eliminate redundant hash operation on link signatures
---
 src/exchange/taler-exchange-httpd_refreshes_reveal.c | 10 ++++++++--
 src/exchangedb/plugin_exchangedb_postgres.c          |  6 ++++--
 src/include/taler_crypto_lib.h                       |  6 ++----
 src/include/taler_exchangedb_plugin.h                | 16 +++++++++++-----
 src/lib/exchange_api_link.c                          |  8 ++++++--
 src/util/wallet_signatures.c                         | 10 +++-------
 6 files changed, 34 insertions(+), 22 deletions(-)

diff --git a/src/exchange/taler-exchange-httpd_refreshes_reveal.c 
b/src/exchange/taler-exchange-httpd_refreshes_reveal.c
index 1cd28048..551e8410 100644
--- a/src/exchange/taler-exchange-httpd_refreshes_reveal.c
+++ b/src/exchange/taler-exchange-httpd_refreshes_reveal.c
@@ -297,11 +297,14 @@ resolve_refreshes_reveal_denominations (struct 
MHD_Connection *connection,
 {
   unsigned int num_fresh_coins = json_array_size (new_denoms_h_json);
   /* We know num_fresh_coins is bounded by #MAX_FRESH_COINS, so this is safe */
+  // FIXME: messy to have so many arrays -- and then
+  // later we copy them around! Avoidable!?!
   const struct TEH_DenominationKey *dks[num_fresh_coins];
   struct TALER_DenominationHash dk_h[num_fresh_coins];
   struct TALER_RefreshCoinData rcds[num_fresh_coins];
   struct TALER_CoinSpendSignatureP link_sigs[num_fresh_coins];
   struct TALER_BlindedDenominationSignature ev_sigs[num_fresh_coins];
+  struct TALER_BlindedCoinHash h_blind_ev[num_fresh_coins];
   MHD_RESULT ret;
   struct TEH_KeyStateHandle *ksh;
   uint64_t melt_serial_id;
@@ -398,6 +401,9 @@ resolve_refreshes_reveal_denominations (struct 
MHD_Connection *connection,
         GNUNET_free (rcds[j].coin_ev);
       return (GNUNET_NO == res) ? MHD_YES : MHD_NO;
     }
+    GNUNET_CRYPTO_hash (rcd->coin_ev,
+                        rcd->coin_ev_size,
+                        &h_blind_ev[i].hash);
     rcd->dk = &dks[i]->denom_pub;
   }
 
@@ -468,8 +474,7 @@ resolve_refreshes_reveal_denominations (struct 
MHD_Connection *connection,
         TALER_wallet_link_verify (
           &dk_h[i],
           &rctx->gamma_tp,
-          rcds[i].coin_ev,
-          rcds[i].coin_ev_size,
+          &h_blind_ev[i],
           &rctx->melt.session.coin.coin_pub,
           &link_sigs[i]))
     {
@@ -529,6 +534,7 @@ resolve_refreshes_reveal_denominations (struct 
MHD_Connection *connection,
       rrc->coin_ev = rcds[i].coin_ev;
       rrc->coin_ev_size = rcds[i].coin_ev_size;
       rrc->coin_sig = ev_sigs[i];
+      rrc->coin_envelope_hash = h_blind_ev[i];
     }
     qs = TEH_plugin->insert_refresh_reveal (TEH_plugin->cls,
                                             melt_serial_id,
diff --git a/src/exchangedb/plugin_exchangedb_postgres.c 
b/src/exchangedb/plugin_exchangedb_postgres.c
index d5290d9c..32b04403 100644
--- a/src/exchangedb/plugin_exchangedb_postgres.c
+++ b/src/exchangedb/plugin_exchangedb_postgres.c
@@ -906,6 +906,7 @@ prepare_statements (struct PostgresClosure *pg)
       "SELECT "
       " rrc.freshcoin_index"
       ",denom.denom_pub_hash"
+      ",rrc.h_coin_ev"
       ",rrc.link_sig"
       ",rrc.coin_ev"
       ",rrc.ev_sig"
@@ -6113,8 +6114,7 @@ postgres_insert_refresh_reveal (
       GNUNET_PQ_query_param_auto_from_type (tp),
       GNUNET_PQ_query_param_fixed_size (
         tprivs,
-        num_tprivs
-        * sizeof (struct TALER_TransferPrivateKeyP)),
+        num_tprivs * sizeof (struct TALER_TransferPrivateKeyP)),
       GNUNET_PQ_query_param_end
     };
 
@@ -6199,6 +6199,8 @@ add_revealed_coins (void *cls,
                                               &rrc->h_denom_pub),
         GNUNET_PQ_result_spec_auto_from_type ("link_sig",
                                               &rrc->orig_coin_link_sig),
+        GNUNET_PQ_result_spec_auto_from_type ("h_coin_ev",
+                                              &rrc->coin_envelope_hash),
         GNUNET_PQ_result_spec_variable_size ("coin_ev",
                                              (void **) &rrc->coin_ev,
                                              &rrc->coin_ev_size),
diff --git a/src/include/taler_crypto_lib.h b/src/include/taler_crypto_lib.h
index db38c0c2..e6c5e2a4 100644
--- a/src/include/taler_crypto_lib.h
+++ b/src/include/taler_crypto_lib.h
@@ -1788,8 +1788,7 @@ TALER_wallet_link_sign (const struct 
TALER_DenominationHash *h_denom_pub,
  *
  * @param h_denom_pub hash of the denomiantion public key of the new coin
  * @param transfer_pub transfer public key
- * @param coin_ev coin envelope
- * @param coin_ev_size number of bytes in @a coin_ev
+ * @param h_coin_ev hash of the coin envelope
  * @param old_coin_pub old coin key that the link signature is for
  * @param coin_sig resulting signature
  * @return #GNUNET_OK if the signature is valid
@@ -1798,8 +1797,7 @@ enum GNUNET_GenericReturnValue
 TALER_wallet_link_verify (
   const struct TALER_DenominationHash *h_denom_pub,
   const struct TALER_TransferPublicKeyP *transfer_pub,
-  const void *coin_ev,
-  size_t coin_ev_size,
+  const struct TALER_BlindedCoinHash *h_coin_ev,
   const struct TALER_CoinSpendPublicKeyP *old_coin_pub,
   const struct TALER_CoinSpendSignatureP *coin_sig);
 
diff --git a/src/include/taler_exchangedb_plugin.h 
b/src/include/taler_exchangedb_plugin.h
index 357d9f07..3c7840ef 100644
--- a/src/include/taler_exchangedb_plugin.h
+++ b/src/include/taler_exchangedb_plugin.h
@@ -1635,6 +1635,16 @@ struct TALER_EXCHANGEDB_RefreshRevealedCoin
    */
   struct TALER_CoinSpendSignatureP orig_coin_link_sig;
 
+  /**
+   * Hash of the blinded new coin, that is @e coin_ev.
+   */
+  struct TALER_BlindedCoinHash coin_envelope_hash;
+
+  /**
+   * Signature generated by the exchange over the coin (in blinded format).
+   */
+  struct TALER_BlindedDenominationSignature coin_sig;
+
   /**
    * Blinded message to be signed (in envelope), with @e coin_env_size bytes.
    */
@@ -1645,10 +1655,6 @@ struct TALER_EXCHANGEDB_RefreshRevealedCoin
    */
   size_t coin_ev_size;
 
-  /**
-   * Signature generated by the exchange over the coin (in blinded format).
-   */
-  struct TALER_BlindedDenominationSignature coin_sig;
 };
 
 
@@ -2972,7 +2978,7 @@ struct TALER_EXCHANGEDB_Plugin
 
 
   /**
-   * Lookup in the database for the @a num_freshcoins coins that we
+   * Lookup in the database for the fresh coins that we
    * created in the given refresh operation.
    *
    * @param cls the @e cls of this struct with the plugin-specific state
diff --git a/src/lib/exchange_api_link.c b/src/lib/exchange_api_link.c
index 55d3bdb6..ec085b53 100644
--- a/src/lib/exchange_api_link.c
+++ b/src/lib/exchange_api_link.c
@@ -138,6 +138,7 @@ parse_link_coin (const struct TALER_EXCHANGE_LinkHandle *lh,
     struct TALER_PlanchetDetail pd;
     struct TALER_CoinPubHash c_hash;
     struct TALER_CoinSpendPublicKeyP old_coin_pub;
+    struct TALER_BlindedCoinHash coin_envelope_hash;
 
     GNUNET_CRYPTO_eddsa_key_get_public (&lh->coin_priv.eddsa_priv,
                                         &old_coin_pub.eddsa_pub);
@@ -151,11 +152,14 @@ parse_link_coin (const struct TALER_EXCHANGE_LinkHandle 
*lh,
       GNUNET_JSON_parse_free (spec);
       return GNUNET_SYSERR;
     }
+    GNUNET_CRYPTO_hash (pd.coin_ev,
+                        pd.coin_ev_size,
+                        &coin_envelope_hash.hash);
+
     if (GNUNET_OK !=
         TALER_wallet_link_verify (&pd.denom_pub_hash,
                                   trans_pub,
-                                  pd.coin_ev,
-                                  pd.coin_ev_size,
+                                  &coin_envelope_hash,
                                   &old_coin_pub,
                                   &link_sig))
     {
diff --git a/src/util/wallet_signatures.c b/src/util/wallet_signatures.c
index 9c3723b0..c46dd670 100644
--- a/src/util/wallet_signatures.c
+++ b/src/util/wallet_signatures.c
@@ -133,9 +133,7 @@ enum GNUNET_GenericReturnValue
 TALER_wallet_link_verify (
   const struct TALER_DenominationHash *h_denom_pub,
   const struct TALER_TransferPublicKeyP *transfer_pub,
-  // FIXME: consider passing hash!
-  const void *coin_ev,
-  size_t coin_ev_size,
+  const struct TALER_BlindedCoinHash *h_coin_ev,
   const struct TALER_CoinSpendPublicKeyP *old_coin_pub,
   const struct TALER_CoinSpendSignatureP *coin_sig)
 {
@@ -143,12 +141,10 @@ TALER_wallet_link_verify (
     .purpose.size = htonl (sizeof (ldp)),
     .purpose.purpose = htonl (TALER_SIGNATURE_WALLET_COIN_LINK),
     .h_denom_pub = *h_denom_pub,
-    .transfer_pub = *transfer_pub
+    .transfer_pub = *transfer_pub,
+    .coin_envelope_hash = *h_coin_ev
   };
 
-  GNUNET_CRYPTO_hash (coin_ev,
-                      coin_ev_size,
-                      &ldp.coin_envelope_hash.hash);
   return
     GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_WALLET_COIN_LINK,
                                 &ldp,

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