[age restriction] progress 16/n - refresh/reveal/link tests

Age restriction works now with withdraw, melt/refresh/reveal and link,
including tests.

However, there is still a problem with the tests:  The melting operation
"refresh-melt-failing-age" that should fail (because of conflict), but
currently fails for other reasons.  I decided to disable that particular
test (and the next) and submit the patch I have so far.

6 files changed, 76 insertions, 60 deletions

diff --git a/src/lib/exchange_api_common.c b/src/lib/exchange_api_common.c
index 17e00a813..b7a43bbc8 100644
--- a/src/lib/exchange_api_common.c
+++ b/src/lib/exchange_api_common.c
@@ -585,24 +585,20 @@ TALER_EXCHANGE_verify_coin_history (
         }
       }
 
-      {
-        const struct TALER_AgeCommitmentHash *ahc = &h_age_commitment;
-
-        if (TALER_AgeCommitmentHash_isNullOrZero (ahc))
-          ahc = NULL;
 
-        if (GNUNET_OK !=
-            TALER_wallet_melt_verify (&amount,
-                                      &fee,
-                                      &rc,
-                                      h_denom_pub,
-                                      ahc,
-                                      coin_pub,
-                                      &sig))
-        {
-          GNUNET_break_op (0);
-          return GNUNET_SYSERR;
-        }
+      if (GNUNET_OK !=
+          TALER_wallet_melt_verify (
+            &amount,
+            &fee,
+            &rc,
+            h_denom_pub,
+            TALER_AgeCommitmentHash_isNullOrZero (&h_age_commitment) ?
+            NULL : &h_age_commitment,
+            coin_pub,
+            &sig))
+      {
+        GNUNET_break_op (0);
+        return GNUNET_SYSERR;
       }
       add = GNUNET_YES;
     }
diff --git a/src/lib/exchange_api_link.c b/src/lib/exchange_api_link.c
index 902f2b422..ac3fecdde 100644
--- a/src/lib/exchange_api_link.c
+++ b/src/lib/exchange_api_link.c
@@ -67,7 +67,8 @@ struct TALER_EXCHANGE_LinkHandle
   struct TALER_CoinSpendPrivateKeyP coin_priv;
 
   /**
-   * Age commitment of the coin, might be NULL, required to re-generate age commitments
+   * Age commitment of the original coin, might be NULL.
+   * Required to derive the new age commitment
    */
   const struct TALER_AgeCommitment *age_commitment;
 
@@ -118,7 +119,6 @@ parse_link_coin (const struct TALER_EXCHANGE_LinkHandle *lh,
   struct TALER_TransferSecretP secret;
   struct TALER_PlanchetDetail pd;
   struct TALER_CoinPubHashP c_hash;
-  struct TALER_AgeCommitmentHash *hac = NULL;
 
   /* parse reply */
   memset (&nonce,
@@ -145,28 +145,26 @@ parse_link_coin (const struct TALER_EXCHANGE_LinkHandle *lh,
                                          &alg_values,
                                          &bks);
 
+  lci->age_commitment = NULL;
+  lci->h_age_commitment = NULL;
+
   /* Derive the age commitment and calculate the hash */
   if (NULL != lh->age_commitment)
   {
-    struct TALER_AgeCommitment nac = {0};
-    struct TALER_AgeCommitmentHash h = {0};
-    uint32_t seed  = secret.key.bits[0];
+    uint64_t seed  = (uint64_t) secret.key.bits[0]
+                     | (uint64_t) secret.key.bits[1] << 32;
+    lci->age_commitment = GNUNET_new (struct TALER_AgeCommitment);
+    lci->h_age_commitment = GNUNET_new (struct TALER_AgeCommitmentHash);
 
-    if (GNUNET_OK !=
-        TALER_age_commitment_derive (
-          lh->age_commitment,
-          seed,
-          &nac))
-    {
-      GNUNET_break_op (0);
-      return GNUNET_SYSERR;
-    }
+    GNUNET_assert (GNUNET_OK ==
+                   TALER_age_commitment_derive (
+                     lh->age_commitment,
+                     seed,
+                     lci->age_commitment));
 
     TALER_age_commitment_hash (
-      &nac,
-      &h);
-
-    hac = &h;
+      lci->age_commitment,
+      lci->h_age_commitment);
   }
 
   if (GNUNET_OK !=
@@ -174,7 +172,7 @@ parse_link_coin (const struct TALER_EXCHANGE_LinkHandle *lh,
                               &alg_values,
                               &bks,
                               &lci->coin_priv,
-                              hac,
+                              lci->h_age_commitment,
                               &c_hash,
                               &pd))
   {
diff --git a/src/lib/exchange_api_melt.c b/src/lib/exchange_api_melt.c
index f7f770272..dbe77c7eb 100644
--- a/src/lib/exchange_api_melt.c
+++ b/src/lib/exchange_api_melt.c
@@ -478,6 +478,7 @@ start_melt (struct TALER_EXCHANGE_MeltHandle *mh)
                           &mh->md.melted_coin.fee_melt,
                           &mh->md.rc,
                           &h_denom_pub,
+                          mh->md.melted_coin.h_age_commitment,
                           &mh->md.melted_coin.coin_priv,
                           &confirm_sig);
   GNUNET_CRYPTO_eddsa_key_get_public (&mh->md.melted_coin.coin_priv.eddsa_priv,
@@ -494,6 +495,12 @@ start_melt (struct TALER_EXCHANGE_MeltHandle *mh)
     GNUNET_JSON_pack_data_auto ("rc",
                                 &mh->md.rc),
     GNUNET_JSON_pack_allow_null (
+      mh->md.melted_coin.h_age_commitment
+       ? GNUNET_JSON_pack_data_auto ("age_commitment_hash",
+                                     mh->md.melted_coin.h_age_commitment)
+       : GNUNET_JSON_pack_string ("age_commitment_hash",
+                                  NULL)),
+    GNUNET_JSON_pack_allow_null (
       mh->send_rms
        ? GNUNET_JSON_pack_data_auto ("rms",
                                      &mh->rms)
diff --git a/src/lib/exchange_api_refresh_common.c b/src/lib/exchange_api_refresh_common.c
index 8e9e8da37..997d1fec8 100644
--- a/src/lib/exchange_api_refresh_common.c
+++ b/src/lib/exchange_api_refresh_common.c
@@ -78,7 +78,8 @@ TALER_EXCHANGE_get_melt_data_ (
   md->melted_coin.fee_melt = rd->melt_pk.fees.refresh;
   md->melted_coin.original_value = rd->melt_pk.value;
   md->melted_coin.expire_deposit = rd->melt_pk.expire_deposit;
-  md->melted_coin.age_commitment = rd->age_commitment;
+  md->melted_coin.age_commitment = rd->melt_age_commitment;
+  md->melted_coin.h_age_commitment = rd->melt_h_age_commitment;
 
   GNUNET_assert (GNUNET_OK ==
                  TALER_amount_set_zero (rd->melt_amount.currency,
@@ -184,29 +185,23 @@ TALER_EXCHANGE_get_melt_data_ (
       /* Handle age commitment, if present */
       if (NULL != md->melted_coin.age_commitment)
       {
-        struct TALER_AgeCommitment new_ac;
-        struct TALER_AgeCommitmentHash hac;
-
-        /* We use the first 4 bytes of the trans_sec to generate a new age
+        /* We use the first 8 bytes of the trans_sec to generate a new age
          * commitment */
-        uint32_t age_seed = trans_sec.key.bits[0];
-
-        if (GNUNET_OK !=
-            TALER_age_commitment_derive (
-              md->melted_coin.age_commitment,
-              age_seed + j,
-              &new_ac))
-        {
-          GNUNET_break_op (0);
-          TALER_EXCHANGE_free_melt_data_ (md);
-          return GNUNET_SYSERR;
-        }
+        uint64_t age_seed = (uint64_t) trans_sec.key.bits[0]
+                            | (uint64_t) trans_sec.key.bits[1] << 32;
 
-        TALER_age_commitment_hash (
-          &new_ac,
-          &hac);
+        fcd->age_commitment[i] = GNUNET_new (struct TALER_AgeCommitment);
+        ach = GNUNET_new (struct TALER_AgeCommitmentHash);
+
+        GNUNET_assert (GNUNET_OK ==
+                       TALER_age_commitment_derive (
+                         md->melted_coin.age_commitment,
+                         age_seed,
+                         fcd->age_commitment[i]));
 
-        ach = &hac;
+        TALER_age_commitment_hash (
+          fcd->age_commitment[i],
+          ach);
       }
 
       if (TALER_DENOMINATION_CS == alg_values[j].cipher)
@@ -225,7 +220,6 @@ TALER_EXCHANGE_get_melt_data_ (
         TALER_EXCHANGE_free_melt_data_ (md);
         return GNUNET_SYSERR;
       }
-
       rcd->blinded_planchet = pd.blinded_planchet;
       rcd->dk = &fcd->fresh_pk;
     }
diff --git a/src/lib/exchange_api_refresh_common.h b/src/lib/exchange_api_refresh_common.h
index a3c3e2c02..8d7eb282e 100644
--- a/src/lib/exchange_api_refresh_common.h
+++ b/src/lib/exchange_api_refresh_common.h
@@ -56,8 +56,8 @@ struct MeltedCoin
    * The original age commitment and its hash.  MUST be NULL if no age
    * commitment was set.
    */
-  struct TALER_AgeCommitment *age_commitment;
-  struct TALER_AgeCommitmentHash *h_age_commitment;
+  const struct TALER_AgeCommitment *age_commitment;
+  const struct TALER_AgeCommitmentHash *h_age_commitment;
 
   /**
    * Timestamp indicating when coins of this denomination become invalid.
diff --git a/src/lib/exchange_api_refreshes_reveal.c b/src/lib/exchange_api_refreshes_reveal.c
index 461432db7..881c7e731 100644
--- a/src/lib/exchange_api_refreshes_reveal.c
+++ b/src/lib/exchange_api_refreshes_reveal.c
@@ -336,6 +336,7 @@ TALER_EXCHANGE_refreshes_reveal (
   json_t *coin_evs;
   json_t *reveal_obj;
   json_t *link_sigs;
+  json_t *old_age_commitment = NULL;
   CURL *eh;
   struct GNUNET_CURL_Context *ctx;
   struct MeltData md;
@@ -427,6 +428,22 @@ TALER_EXCHANGE_refreshes_reveal (
                                             &md.transfer_priv[j])));
   }
 
+  /* build array of old age commitment, if applicable */
+  GNUNET_assert ((NULL == rd->melt_age_commitment) ==
+                 (NULL == rd->melt_h_age_commitment));
+  if (NULL != rd->melt_age_commitment)
+  {
+    GNUNET_assert (NULL != (old_age_commitment = json_array ()));
+
+    for (size_t i = 0; i < rd->melt_age_commitment->num_pub; i++)
+    {
+      GNUNET_assert (0 ==
+                     json_array_append_new (old_age_commitment,
+                                            GNUNET_JSON_from_data_auto (
+                                              &rd->melt_age_commitment->pub[i])));
+    }
+  }
+
   /* build main JSON request */
   reveal_obj = GNUNET_JSON_PACK (
     GNUNET_JSON_pack_data_auto ("transfer_pub",
@@ -437,6 +454,9 @@ TALER_EXCHANGE_refreshes_reveal (
                                     rms)
       : GNUNET_JSON_pack_string ("rms",
                                  NULL)),
+    GNUNET_JSON_pack_allow_null (
+      GNUNET_JSON_pack_array_steal ("old_age_commitment",
+                                    old_age_commitment)),
     GNUNET_JSON_pack_array_steal ("transfer_privs",
                                   transfer_privs),
     GNUNET_JSON_pack_array_steal ("link_sigs",
@@ -480,6 +500,7 @@ TALER_EXCHANGE_refreshes_reveal (
     GNUNET_free (rrh);
     return NULL;
   }
+
   eh = TALER_EXCHANGE_curl_easy_get_ (rrh->url);
   if ( (NULL == eh) ||
        (GNUNET_OK !=