Refactoring TALER_AgeCommitment

Instead of a single struct TALER_AgeCommitment, we now use
 1. TALER_AgeCommitment for the age mask and list public keys for age
    restriciton.
 2. TALER_AgeProof for list of private keys for age restriction
 3. TALER_AgeCommitmentProof for the aggregation of the former two.

Also, we introduce TALER_AgeAttestation as the EDDSA signature to attest
a particular age group, along with the function prototypes
TALER_age_commitment_attest and TALER_age_commitment_verify.

3 files changed, 40 insertions, 38 deletions

diff --git a/src/testing/testing_api_cmd_deposit.c b/src/testing/testing_api_cmd_deposit.c
index 33c1db447..2b9486ca5 100644
--- a/src/testing/testing_api_cmd_deposit.c
+++ b/src/testing/testing_api_cmd_deposit.c
@@ -287,7 +287,7 @@ deposit_run (void *cls,
   const struct TALER_TESTING_Command *coin_cmd;
   const struct TALER_CoinSpendPrivateKeyP *coin_priv;
   struct TALER_CoinSpendPublicKeyP coin_pub;
-  const struct TALER_AgeCommitment *age_commitment = NULL;
+  const struct TALER_AgeCommitmentProof *age_commitment_proof = NULL;
   struct TALER_AgeCommitmentHash h_age_commitment = {0};
   const struct TALER_EXCHANGE_DenomPublicKey *denom_pub;
   const struct TALER_DenominationSignature *denom_pub_sig;
@@ -385,9 +385,9 @@ deposit_run (void *cls,
                                            ds->coin_index,
                                            &coin_priv)) ||
        (GNUNET_OK !=
-        TALER_TESTING_get_trait_age_commitment (coin_cmd,
-                                                ds->coin_index,
-                                                &age_commitment)) ||
+        TALER_TESTING_get_trait_age_commitment_proof (coin_cmd,
+                                                      ds->coin_index,
+                                                      &age_commitment_proof)) ||
        (GNUNET_OK !=
         TALER_TESTING_get_trait_denom_pub (coin_cmd,
                                            ds->coin_index,
@@ -405,9 +405,10 @@ deposit_run (void *cls,
     return;
   }
 
-  if (NULL != age_commitment)
+  if (NULL != age_commitment_proof)
   {
-    TALER_age_commitment_hash (age_commitment, &h_age_commitment);
+    TALER_age_commitment_hash (&age_commitment_proof->commitment,
+                               &h_age_commitment);
   }
   ds->deposit_fee = denom_pub->fees.deposit;
   GNUNET_CRYPTO_eddsa_key_get_public (&coin_priv->eddsa_priv,
@@ -533,7 +534,7 @@ deposit_traits (void *cls,
   const struct TALER_TESTING_Command *coin_cmd;
   /* Will point to coin cmd internals. */
   const struct TALER_CoinSpendPrivateKeyP *coin_spent_priv;
-  const struct TALER_AgeCommitment *age_commitment;
+  const struct TALER_AgeCommitmentProof *age_commitment_proof;
 
   if (GNUNET_YES != ds->command_initialized)
   {
@@ -556,9 +557,9 @@ deposit_traits (void *cls,
                                          ds->coin_index,
                                          &coin_spent_priv) ||
       (GNUNET_OK !=
-       TALER_TESTING_get_trait_age_commitment (coin_cmd,
-                                               ds->coin_index,
-                                               &age_commitment)))
+       TALER_TESTING_get_trait_age_commitment_proof (coin_cmd,
+                                                     ds->coin_index,
+                                                     &age_commitment_proof)))
   {
     GNUNET_break (0);
     TALER_TESTING_interpreter_fail (ds->is);
@@ -573,8 +574,8 @@ deposit_traits (void *cls,
       /* These traits are always available */
       TALER_TESTING_make_trait_coin_priv (index,
                                           coin_spent_priv),
-      TALER_TESTING_make_trait_age_commitment (index,
-                                               age_commitment),
+      TALER_TESTING_make_trait_age_commitment_proof (index,
+                                                     age_commitment_proof),
       TALER_TESTING_make_trait_wire_details (ds->wire_details),
       TALER_TESTING_make_trait_contract_terms (ds->contract_terms),
       TALER_TESTING_make_trait_merchant_priv (&ds->merchant_priv),
diff --git a/src/testing/testing_api_cmd_refresh.c b/src/testing/testing_api_cmd_refresh.c
index 9a81a603d..e2ed8b216 100644
--- a/src/testing/testing_api_cmd_refresh.c
+++ b/src/testing/testing_api_cmd_refresh.c
@@ -71,9 +71,10 @@ struct TALER_TESTING_FreshCoinData
   struct TALER_CoinSpendPrivateKeyP coin_priv;
 
   /*
-   * Fresh age commitment for the coin and its hash, NULL if not applicable.
+   * Fresh age commitment for the coin with proof and its hash, NULL if not
+   * applicable.
    */
-  struct TALER_AgeCommitment *age_commitment;
+  struct TALER_AgeCommitmentProof *age_commitment_proof;
   struct TALER_AgeCommitmentHash *h_age_commitment;
 
   /**
@@ -441,7 +442,7 @@ reveal_cb (void *cls,
         return;
       }
       fc->coin_priv = coin->coin_priv;
-      fc->age_commitment = coin->age_commitment;
+      fc->age_commitment_proof = coin->age_commitment_proof;
       fc->h_age_commitment = coin->h_age_commitment;
 
       TALER_denom_sig_deep_copy (&fc->sig,
@@ -834,7 +835,7 @@ refresh_link_run (void *cls,
   /* finally, use private key from withdraw sign command */
   rls->rlh = TALER_EXCHANGE_link (is->exchange,
                                   coin_priv,
-                                  rms->refresh_data.melt_age_commitment,
+                                  rms->refresh_data.melt_age_commitment_proof,
                                   &link_cb,
                                   rls);
 
@@ -1044,7 +1045,7 @@ melt_run (void *cls,
   {
     struct TALER_Amount melt_amount;
     struct TALER_Amount fresh_amount;
-    const struct TALER_AgeCommitment *age_commitment;
+    const struct TALER_AgeCommitmentProof *age_commitment_proof;
     const struct TALER_AgeCommitmentHash *h_age_commitment;
     const struct TALER_DenominationSignature *melt_sig;
     const struct TALER_EXCHANGE_DenomPublicKey *melt_denom_pub;
@@ -1072,9 +1073,9 @@ melt_run (void *cls,
     }
 
     if (GNUNET_OK !=
-        TALER_TESTING_get_trait_age_commitment (coin_command,
-                                                0,
-                                                &age_commitment))
+        TALER_TESTING_get_trait_age_commitment_proof (coin_command,
+                                                      0,
+                                                      &age_commitment_proof))
     {
       GNUNET_break (0);
       TALER_TESTING_interpreter_fail (rms->is);
@@ -1159,13 +1160,13 @@ melt_run (void *cls,
     rms->refresh_data.melt_amount = melt_amount;
     rms->refresh_data.melt_sig = *melt_sig;
     rms->refresh_data.melt_pk = *melt_denom_pub;
-    rms->refresh_data.melt_age_commitment = age_commitment;
+    rms->refresh_data.melt_age_commitment_proof = age_commitment_proof;
     rms->refresh_data.melt_h_age_commitment = h_age_commitment;
     rms->refresh_data.fresh_pks = rms->fresh_pks;
     rms->refresh_data.fresh_pks_len = num_fresh_coins;
 
     GNUNET_assert (age_restricted ==
-                   (NULL != age_commitment));
+                   (NULL != age_commitment_proof));
 
     rms->rmh = TALER_EXCHANGE_melt (is->exchange,
                                     &rms->rms,
@@ -1251,9 +1252,9 @@ melt_traits (void *cls,
                                           &rms->fresh_pks[index]),
       TALER_TESTING_make_trait_coin_priv (index,
                                           rms->melt_priv),
-      TALER_TESTING_make_trait_age_commitment (
+      TALER_TESTING_make_trait_age_commitment_proof (
         index,
-        rms->refresh_data.melt_age_commitment),
+        rms->refresh_data.melt_age_commitment_proof),
       TALER_TESTING_make_trait_h_age_commitment (
         index,
         rms->refresh_data.melt_h_age_commitment),
@@ -1421,9 +1422,9 @@ refresh_reveal_traits (void *cls,
       TALER_TESTING_make_trait_coin_priv (
         index,
         &rrs->fresh_coins[index].coin_priv),
-      TALER_TESTING_make_trait_age_commitment (
+      TALER_TESTING_make_trait_age_commitment_proof (
         index,
-        rrs->fresh_coins[index].age_commitment),
+        rrs->fresh_coins[index].age_commitment_proof),
       TALER_TESTING_make_trait_h_age_commitment (
         index,
         rrs->fresh_coins[index].h_age_commitment),
diff --git a/src/testing/testing_api_cmd_withdraw.c b/src/testing/testing_api_cmd_withdraw.c
index 3974a1057..1c24d5a6c 100644
--- a/src/testing/testing_api_cmd_withdraw.c
+++ b/src/testing/testing_api_cmd_withdraw.c
@@ -138,10 +138,10 @@ struct WithdrawState
   uint8_t age;
 
   /**
-   * If age > 0, put here the corresponding age commitment and its hash,
-   * respectivelly, NULL otherwise.
+   * If age > 0, put here the corresponding age commitment with its proof and
+   * its hash, respectivelly, NULL otherwise.
    */
-  struct TALER_AgeCommitment *age_commitment;
+  struct TALER_AgeCommitmentProof *age_commitment_proof;
   struct TALER_AgeCommitmentHash *h_age_commitment;
 
   /**
@@ -524,10 +524,10 @@ withdraw_cleanup (void *cls,
     TALER_EXCHANGE_destroy_denomination_key (ws->pk);
     ws->pk = NULL;
   }
-  if (NULL != ws->age_commitment)
+  if (NULL != ws->age_commitment_proof)
   {
-    TALER_age_commitment_free (ws->age_commitment);
-    ws->age_commitment = NULL;
+    TALER_age_commitment_proof_free (ws->age_commitment_proof);
+    ws->age_commitment_proof = NULL;
   }
   if (NULL != ws->h_age_commitment)
   {
@@ -579,7 +579,7 @@ withdraw_traits (void *cls,
       (const char **) &ws->reserve_payto_uri),
     TALER_TESTING_make_trait_exchange_url (
       (const char **) &ws->exchange_url),
-    TALER_TESTING_make_trait_age_commitment (0, ws->age_commitment),
+    TALER_TESTING_make_trait_age_commitment_proof (0, ws->age_commitment_proof),
     TALER_TESTING_make_trait_h_age_commitment (0, ws->h_age_commitment),
     TALER_TESTING_trait_end ()
   };
@@ -619,12 +619,12 @@ TALER_TESTING_cmd_withdraw_amount (const char *label,
   ws->age = age;
   if (0 < age)
   {
-    struct TALER_AgeCommitment *ac;
+    struct TALER_AgeCommitmentProof *acp;
     struct TALER_AgeCommitmentHash *hac;
     uint32_t seed;
     struct TALER_AgeMask mask;
 
-    ac = GNUNET_new (struct TALER_AgeCommitment);
+    acp = GNUNET_new (struct TALER_AgeCommitmentProof);
     hac = GNUNET_new (struct TALER_AgeCommitmentHash);
     seed = GNUNET_CRYPTO_random_u64 (GNUNET_CRYPTO_QUALITY_WEAK, UINT64_MAX);
     mask = TALER_extensions_age_restriction_ageMask ();
@@ -634,7 +634,7 @@ TALER_TESTING_cmd_withdraw_amount (const char *label,
           &mask,
           age,
           seed,
-          ac))
+          acp))
     {
       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                   "Failed to generate age commitment for age %d at %s\n",
@@ -643,8 +643,8 @@ TALER_TESTING_cmd_withdraw_amount (const char *label,
       GNUNET_assert (0);
     }
 
-    TALER_age_commitment_hash (ac,hac);
-    ws->age_commitment = ac;
+    TALER_age_commitment_hash (&acp->commitment,hac);
+    ws->age_commitment_proof = acp;
     ws->h_age_commitment = hac;
   }