[age restriction] progress 14/n - withdraw and deposit

Age restriction support for
  - withdraw is done and tested
  - deposit is done and tested

TODOs:
  - melt/refresh/reveal
  - link

------

Added functions
 - TALER_age_restriction_commit
 - TALER_age_commitment_derive
 - TALER_age_commitment_hash
 - TALER_age_restriction_commitment_free_inside
 - Hash of age commitment passed around API boundaries

Exchangedb adjustments for denominations
 - all prepared statements re: denominations now handle age_mask
 - signature parameters adjusted

Hash and signature verification of /keys adjusted
 - Hashes of (normal) denominations and age-restricted denominations are
   calculated seperately
 - The hash of the age-restricted ones will then be added to the other
   hash
 - The total hash is signed/verified

Tests for withdraw with age restriction added
 - TALER_EXCHANGE_DenomPublickey now carries age_mask
 - TALER_TESTING_cmd_withdraw_amount* takes age parameter
 - TALER_TESTING_find_pk takes boolean age_restricted
 - WithdrawState carries age_commitment and its hash
 - withdraw_run derives new age commitment, if applicable
 - Added age parameter to testing (13 as example)

Various Fixes and changes
 - Fixes of post handler for /management/extensions
 - Fixes for offline tool extensions signing
 - Slight refactoring of extensions
 - Age restriction extension simplified
   - config is now global to extension
   - added global TEH_age_restriction_enabled and TEH_age_mask in
     taler-exchange-httpd
   - helper functions and macros introduced

11 files changed, 134 insertions, 40 deletions

diff --git a/src/lib/exchange_api_common.c b/src/lib/exchange_api_common.c
index 53a75a934..d03409244 100644
--- a/src/lib/exchange_api_common.c
+++ b/src/lib/exchange_api_common.c
@@ -477,6 +477,7 @@ TALER_EXCHANGE_verify_coin_history (
       struct TALER_MerchantPublicKeyP merchant_pub;
       struct GNUNET_TIME_Timestamp refund_deadline = {0};
       struct TALER_CoinSpendSignatureP sig;
+      struct TALER_AgeCommitmentHash *hac = NULL;
       struct GNUNET_JSON_Specification spec[] = {
         GNUNET_JSON_spec_fixed_auto ("coin_sig",
                                      &sig),
@@ -511,6 +512,7 @@ TALER_EXCHANGE_verify_coin_history (
                                        &fee,
                                        &h_wire,
                                        &h_contract_terms,
+                                       hac,
                                        NULL /* h_extensions! */,
                                        h_denom_pub,
                                        wallet_timestamp,
@@ -543,6 +545,7 @@ TALER_EXCHANGE_verify_coin_history (
     {
       struct TALER_CoinSpendSignatureP sig;
       struct TALER_RefreshCommitmentP rc;
+      struct TALER_AgeCommitmentHash h_age_commitment = {0};
       struct GNUNET_JSON_Specification spec[] = {
         GNUNET_JSON_spec_fixed_auto ("coin_sig",
                                      &sig),
@@ -550,6 +553,9 @@ TALER_EXCHANGE_verify_coin_history (
                                      &rc),
         GNUNET_JSON_spec_fixed_auto ("h_denom_pub",
                                      h_denom_pub),
+        GNUNET_JSON_spec_mark_optional (
+          GNUNET_JSON_spec_fixed_auto ("h_age_commitment",
+                                       &h_age_commitment)),
         TALER_JSON_spec_amount_any ("melt_fee",
                                     &fee),
         GNUNET_JSON_spec_end ()
@@ -563,6 +569,7 @@ TALER_EXCHANGE_verify_coin_history (
         GNUNET_break_op (0);
         return GNUNET_SYSERR;
       }
+
       if (NULL != dk)
       {
         /* check that melt fee matches our expectations from /keys! */
@@ -577,16 +584,25 @@ TALER_EXCHANGE_verify_coin_history (
           return GNUNET_SYSERR;
         }
       }
-      if (GNUNET_OK !=
-          TALER_wallet_melt_verify (&amount,
-                                    &fee,
-                                    &rc,
-                                    h_denom_pub,
-                                    coin_pub,
-                                    &sig))
+
       {
-        GNUNET_break_op (0);
-        return GNUNET_SYSERR;
+        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;
+        }
       }
       add = GNUNET_YES;
     }
diff --git a/src/lib/exchange_api_deposit.c b/src/lib/exchange_api_deposit.c
index 7ff596518..2bfaaf6ce 100644
--- a/src/lib/exchange_api_deposit.c
+++ b/src/lib/exchange_api_deposit.c
@@ -463,6 +463,7 @@ handle_deposit_finished (void *cls,
  * @param h_contract_terms hash of the contact of the merchant with the customer (further details are never disclosed to the exchange)
  * @param ech hash over contract extensions
  * @param coin_pub coin’s public key
+ * @param h_age_commitment coin’s hash of age commitment, might be NULL
  * @param denom_sig exchange’s unblinded signature of the coin
  * @param denom_pub denomination key with which the coin is signed
  * @param denom_pub_hash hash of @a denom_pub
@@ -479,6 +480,7 @@ verify_signatures (const struct TALER_EXCHANGE_DenomPublicKey *dki,
                    const struct TALER_PrivateContractHash *h_contract_terms,
                    const struct TALER_ExtensionContractHash *ech,
                    const struct TALER_CoinSpendPublicKeyP *coin_pub,
+                   const struct TALER_AgeCommitmentHash *h_age_commitment,
                    const struct TALER_DenominationSignature *denom_sig,
                    const struct TALER_DenominationPublicKey *denom_pub,
                    const struct TALER_DenominationHash *denom_pub_hash,
@@ -492,6 +494,7 @@ verify_signatures (const struct TALER_EXCHANGE_DenomPublicKey *dki,
                                    &dki->fee_deposit,
                                    h_wire,
                                    h_contract_terms,
+                                   h_age_commitment,
                                    ech,
                                    denom_pub_hash,
                                    timestamp,
@@ -515,8 +518,12 @@ verify_signatures (const struct TALER_EXCHANGE_DenomPublicKey *dki,
       .coin_pub = *coin_pub,
       .denom_pub_hash = *denom_pub_hash,
       .denom_sig = *denom_sig,
-      .age_commitment_hash = {{{0}}} /* FIXME-Oec */
+      .age_commitment_hash = {{{0}}}
     };
+    if (NULL != h_age_commitment)
+    {
+      coin_info.age_commitment_hash = *h_age_commitment;
+    }
 
     if (GNUNET_YES !=
         TALER_test_coin_valid (&coin_info,
@@ -548,6 +555,7 @@ TALER_EXCHANGE_deposit (
   const char *merchant_payto_uri,
   const struct TALER_WireSaltP *wire_salt,
   const struct TALER_PrivateContractHash *h_contract_terms,
+  const struct TALER_AgeCommitmentHash *h_age_commitment,
   const json_t *extension_details,
   const struct TALER_CoinSpendPublicKeyP *coin_pub,
   const struct TALER_DenominationSignature *denom_sig,
@@ -600,11 +608,14 @@ TALER_EXCHANGE_deposit (
   }
   GNUNET_assert (GNUNET_YES ==
                  TEAH_handle_is_ready (exchange));
+
   /* initialize h_wire */
   TALER_merchant_wire_signature_hash (merchant_payto_uri,
                                       wire_salt,
                                       &h_wire);
+
   key_state = TALER_EXCHANGE_get_keys (exchange);
+
   dki = TALER_EXCHANGE_get_denomination_key (key_state,
                                              denom_pub);
   if (NULL == dki)
@@ -613,6 +624,7 @@ TALER_EXCHANGE_deposit (
     GNUNET_break_op (0);
     return NULL;
   }
+
   if (0 >
       TALER_amount_subtract (&amount_without_fee,
                              amount,
@@ -622,17 +634,18 @@ TALER_EXCHANGE_deposit (
     GNUNET_break_op (0);
     return NULL;
   }
+
   TALER_denom_pub_hash (denom_pub,
                         &denom_pub_hash);
+
   if (GNUNET_OK !=
       verify_signatures (dki,
                          amount,
                          &h_wire,
                          h_contract_terms,
-                         (NULL != extension_details)
-                         ? &ech
-                         : NULL,
+                         (NULL != extension_details) ? &ech : NULL,
                          coin_pub,
+                         h_age_commitment,
                          denom_sig,
                          denom_pub,
                          &denom_pub_hash,
@@ -655,6 +668,9 @@ TALER_EXCHANGE_deposit (
                                 wire_salt),
     GNUNET_JSON_pack_data_auto ("h_contract_terms",
                                 h_contract_terms),
+    GNUNET_JSON_pack_allow_null (
+      GNUNET_JSON_pack_data_auto ("h_age_commitment",
+                                  h_age_commitment)),
     GNUNET_JSON_pack_data_auto ("denom_pub_hash",
                                 &denom_pub_hash),
     TALER_JSON_pack_denom_sig ("ub_sig",
diff --git a/src/lib/exchange_api_handle.c b/src/lib/exchange_api_handle.c
index cf3d69d6a..3243f5e95 100644
--- a/src/lib/exchange_api_handle.c
+++ b/src/lib/exchange_api_handle.c
@@ -667,7 +667,9 @@ decode_keys_json (const json_t *resp_obj,
                   enum TALER_EXCHANGE_VersionCompatibility *vc)
 {
   struct TALER_ExchangeSignatureP sig;
-  struct GNUNET_HashContext *hash_context;
+  struct GNUNET_HashContext *hash_context = NULL;
+  struct GNUNET_HashContext *hash_context_restricted = NULL;
+  bool have_age_restricted_denom = false;
   struct TALER_ExchangePublicKeyP pub;
   const char *currency;
   struct GNUNET_JSON_Specification mspec[] = {
@@ -746,7 +748,6 @@ decode_keys_json (const json_t *resp_obj,
     key_data->version = GNUNET_strdup (ver);
   }
 
-  hash_context = NULL;
   EXITIF (GNUNET_OK !=
           GNUNET_JSON_parse (resp_obj,
                              (check_sig) ? mspec : &mspec[2],
@@ -766,7 +767,10 @@ decode_keys_json (const json_t *resp_obj,
 
   /* parse the master public key and issue date of the response */
   if (check_sig)
+  {
     hash_context = GNUNET_CRYPTO_hash_context_start ();
+    hash_context_restricted = GNUNET_CRYPTO_hash_context_start ();
+  }
 
   /* parse the signing keys */
   {
@@ -829,6 +833,9 @@ decode_keys_json (const json_t *resp_obj,
       EXITIF (GNUNET_OK !=
               TALER_extensions_load_json_config (extensions));
     }
+
+    /* 4. assuming we might have now a new value for age_mask, set it in key_data */
+    key_data->age_mask = TALER_extensions_age_restriction_ageMask ();
   }
 
   /* parse the denomination keys, merging with the
@@ -839,9 +846,15 @@ decode_keys_json (const json_t *resp_obj,
      */
     struct
     { char *name;
-      bool is_optional_age_restriction;} hive[2] = {
-      { "denoms",                false },
-      { "age_restricted_denoms", true  },
+      struct GNUNET_HashContext *hc;
+      bool is_optional_age_restriction;}
+    hive[2] = {
+      { "denoms",
+        hash_context,
+        false },
+      { "age_restricted_denoms",
+        hash_context_restricted,
+        true  }
     };
 
     for (size_t s = 0; s < sizeof(hive) / sizeof(hive[0]); s++)
@@ -853,25 +866,19 @@ decode_keys_json (const json_t *resp_obj,
       denom_keys_array = json_object_get (resp_obj,
                                           hive[s].name);
 
-      EXITIF (NULL == denom_keys_array &&
-              ! hive[s].is_optional_age_restriction);
-
-      if (NULL == denom_keys_array &&
-          hive[s].is_optional_age_restriction)
+      if (NULL == denom_keys_array)
         continue;
 
-      /* if "age_restricted_denoms" exists, age-restriction better be enabled
-       * (that is: mask non-zero) */
-      EXITIF (NULL != denom_keys_array &&
-              hive[s].is_optional_age_restriction &&
-              0 == key_data->age_mask.mask);
-
       EXITIF (JSON_ARRAY != json_typeof (denom_keys_array));
 
       json_array_foreach (denom_keys_array, index, denom_key_obj) {
         struct TALER_EXCHANGE_DenomPublicKey dk;
         bool found = false;
 
+        /* mark that we have at least one age restricted denomination, needed
+         * for the hash calculation and signature verification below. */
+        have_age_restricted_denom |= hive[s].is_optional_age_restriction;
+
         memset (&dk,
                 0,
                 sizeof (dk));
@@ -880,12 +887,7 @@ decode_keys_json (const json_t *resp_obj,
                                      check_sig,
                                      denom_key_obj,
                                      &key_data->master_pub,
-                                     hash_context));
-
-        /* Mark age restriction according where we got this denomination from,
-         * "denoms" or "age_restricted_denoms" */
-        if (hive[s].is_optional_age_restriction)
-          dk.age_restricted = true;
+                                     hive[s].hc));
 
         for (unsigned int j = 0;
              j<key_data->num_denom_keys;
@@ -1044,6 +1046,18 @@ decode_keys_json (const json_t *resp_obj,
       .list_issue_date = GNUNET_TIME_timestamp_hton (key_data->list_issue_date)
     };
 
+    /* If we had any age restricted denominations, add their hash to the end of
+     * the normal denominations. */
+    if (have_age_restricted_denom)
+    {
+      struct GNUNET_HashCode hcr;
+      GNUNET_CRYPTO_hash_context_finish (hash_context_restricted,
+                                         &hcr);
+      GNUNET_CRYPTO_hash_context_read (hash_context,
+                                       &hcr,
+                                       sizeof(struct GNUNET_HashCode));
+    }
+
     GNUNET_CRYPTO_hash_context_finish (hash_context,
                                        &ks.hc);
     hash_context = NULL;
diff --git a/src/lib/exchange_api_link.c b/src/lib/exchange_api_link.c
index a44ccdcea..10ddd471d 100644
--- a/src/lib/exchange_api_link.c
+++ b/src/lib/exchange_api_link.c
@@ -113,6 +113,7 @@ parse_link_coin (const struct TALER_EXCHANGE_LinkHandle *lh,
   struct TALER_TransferSecretP secret;
   struct TALER_PlanchetDetail pd;
   struct TALER_CoinPubHash c_hash;
+  struct TALER_AgeCommitmentHash h_age_commitment = {0}; // TODO, see below.
 
   /* parse reply */
   memset (&nonce,
@@ -143,6 +144,7 @@ parse_link_coin (const struct TALER_EXCHANGE_LinkHandle *lh,
                               &alg_values,
                               &bks,
                               &lci->coin_priv,
+                              NULL, /* FIXME-oec. struct TALER_AgeCommitmentHash */
                               &c_hash,
                               &pd))
   {
@@ -179,6 +181,15 @@ parse_link_coin (const struct TALER_EXCHANGE_LinkHandle *lh,
 
     GNUNET_CRYPTO_eddsa_key_get_public (&lh->coin_priv.eddsa_priv,
                                         &old_coin_pub.eddsa_pub);
+    /*
+     * TODO-oec: Derive the age commitment vector and hash it into
+     * h_age_commitment.
+     * Questions:
+     *   - Where do we get the information about the support for age
+     *     restriction of the denomination?
+     *   - Where do we get the information bout the previous coin's age groups?
+     */
+
     TALER_coin_ev_hash (&pd.blinded_planchet,
                         &pd.denom_pub_hash,
                         &coin_envelope_hash);
@@ -187,6 +198,7 @@ parse_link_coin (const struct TALER_EXCHANGE_LinkHandle *lh,
                                   trans_pub,
                                   &coin_envelope_hash,
                                   &old_coin_pub,
+                                  &h_age_commitment,
                                   &link_sig))
     {
       GNUNET_break_op (0);
diff --git a/src/lib/exchange_api_management_get_keys.c b/src/lib/exchange_api_management_get_keys.c
index 4d6866338..ac419388f 100644
--- a/src/lib/exchange_api_management_get_keys.c
+++ b/src/lib/exchange_api_management_get_keys.c
@@ -32,7 +32,7 @@
 /**
  * Set to 1 for extra debug logging.
  */
-#define DEBUG 0
+#define DEBUG 1  /* FIXME-oec */
 
 
 /**
diff --git a/src/lib/exchange_api_management_post_extensions.c b/src/lib/exchange_api_management_post_extensions.c
index c0ab143f6..87b0e0be8 100644
--- a/src/lib/exchange_api_management_post_extensions.c
+++ b/src/lib/exchange_api_management_post_extensions.c
@@ -151,7 +151,7 @@ TALER_EXCHANGE_management_post_extensions (
   body = GNUNET_JSON_PACK (
     GNUNET_JSON_pack_object_steal ("extensions",
                                    ped->extensions),
-    GNUNET_JSON_pack_data_auto ("extensions_sigs",
+    GNUNET_JSON_pack_data_auto ("extensions_sig",
                                 &ped->extensions_sig));
 
   eh = curl_easy_init ();
@@ -168,7 +168,7 @@ TALER_EXCHANGE_management_post_extensions (
     return NULL;
   }
   json_decref (body);
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
               "Requesting URL '%s'\n",
               ph->url);
   GNUNET_assert (CURLE_OK == curl_easy_setopt (eh,
diff --git a/src/lib/exchange_api_refresh_common.c b/src/lib/exchange_api_refresh_common.c
index e944b79a1..89ee1e178 100644
--- a/src/lib/exchange_api_refresh_common.c
+++ b/src/lib/exchange_api_refresh_common.c
@@ -175,6 +175,7 @@ TALER_EXCHANGE_get_melt_data_ (
                                   &alg_values[j],
                                   bks,
                                   coin_priv,
+                                  NULL, /* FIXME-oec: This needs to be setup !*/
                                   &c_hash,
                                   &pd))
       {
diff --git a/src/lib/exchange_api_refresh_common.h b/src/lib/exchange_api_refresh_common.h
index ab19ad7d1..b6926b51f 100644
--- a/src/lib/exchange_api_refresh_common.h
+++ b/src/lib/exchange_api_refresh_common.h
@@ -53,6 +53,12 @@ struct MeltedCoin
   struct TALER_Amount original_value;
 
   /**
+   * The original age commitment hash.  MUST be all zeroes, if no age
+   * commitment was set.
+   */
+  struct TALER_AgeCommitmentHash h_age_commitment;
+
+  /**
    * Timestamp indicating when coins of this denomination become invalid.
    */
   struct GNUNET_TIME_Timestamp expire_deposit;
@@ -93,6 +99,13 @@ struct FreshCoinData
   struct TALER_CoinSpendPrivateKeyP coin_priv;
 
   /**
+   * Arrays age commitments to be created, one for each cut-and-choose
+   * dimension.  The entries in each list might be NULL and indicate no age
+   * commitment/restriction on the particular coin.
+   */
+  struct TALER_AgeCommitment *age_commitment[TALER_CNC_KAPPA];
+
+  /**
    * Blinding key secrets for the coins, depending on the
    * cut-and-choose.
    */
diff --git a/src/lib/exchange_api_refreshes_reveal.c b/src/lib/exchange_api_refreshes_reveal.c
index 08357c14e..8d04c279a 100644
--- a/src/lib/exchange_api_refreshes_reveal.c
+++ b/src/lib/exchange_api_refreshes_reveal.c
@@ -142,6 +142,7 @@ refresh_reveal_ok (struct TALER_EXCHANGE_RefreshesRevealHandle *rrh,
       &rcis[i];
     const struct FreshCoinData *fcd = &rrh->md.fcds[i];
     const struct TALER_DenominationPublicKey *pk;
+    struct TALER_AgeCommitmentHash *ach = NULL;
     json_t *jsonai;
     struct TALER_BlindedDenominationSignature blind_sig;
     struct TALER_CoinSpendPublicKeyP coin_pub;
@@ -160,6 +161,12 @@ refresh_reveal_ok (struct TALER_EXCHANGE_RefreshesRevealHandle *rrh,
     jsonai = json_array_get (jsona, i);
     GNUNET_assert (NULL != jsonai);
 
+    if (! TALER_AgeCommitmentHash_isNullOrZero (
+          &rrh->md.melted_coin.h_age_commitment))
+    {
+      /* FIXME-oec:  need to pull fresh_ach from somewhere */
+    }
+
     if (GNUNET_OK !=
         GNUNET_JSON_parse (jsonai,
                            spec,
@@ -180,15 +187,15 @@ refresh_reveal_ok (struct TALER_EXCHANGE_RefreshesRevealHandle *rrh,
        hence recomputing it here... */
     GNUNET_CRYPTO_eddsa_key_get_public (&rci->coin_priv.eddsa_priv,
                                         &coin_pub.eddsa_pub);
-    /* FIXME-Oec: Age commitment hash. */
     TALER_coin_pub_hash (&coin_pub,
-                         NULL, /* FIXME-Oec */
+                         ach,
                          &coin_hash);
     if (GNUNET_OK !=
         TALER_planchet_to_coin (pk,
                                 &blind_sig,
                                 &bks,
                                 &rci->coin_priv,
+                                ach,
                                 &coin_hash,
                                 &rrh->alg_values[i],
                                 &coin))
diff --git a/src/lib/exchange_api_refund.c b/src/lib/exchange_api_refund.c
index 94909470a..a9510715b 100644
--- a/src/lib/exchange_api_refund.c
+++ b/src/lib/exchange_api_refund.c
@@ -203,6 +203,7 @@ verify_conflict_history_ok (struct TALER_EXCHANGE_RefundHandle *rh,
       struct TALER_Amount deposit_fee;
       struct TALER_MerchantWireHash h_wire;
       struct TALER_PrivateContractHash h_contract_terms;
+      struct TALER_AgeCommitmentHash h_age_commitment = {{{0}}};
       // struct TALER_ExtensionContractHash h_extensions; // FIXME!
       struct TALER_DenominationHash h_denom_pub;
       struct GNUNET_TIME_Timestamp wallet_timestamp;
@@ -218,6 +219,9 @@ verify_conflict_history_ok (struct TALER_EXCHANGE_RefundHandle *rh,
                                      &h_wire),
         GNUNET_JSON_spec_fixed_auto ("h_denom_pub",
                                      &h_denom_pub),
+        GNUNET_JSON_spec_mark_optional (
+          GNUNET_JSON_spec_fixed_auto ("h_age_commitment",
+                                       &h_age_commitment)),
         GNUNET_JSON_spec_timestamp ("timestamp",
                                     &wallet_timestamp),
         GNUNET_JSON_spec_timestamp ("refund_deadline",
@@ -243,6 +247,7 @@ verify_conflict_history_ok (struct TALER_EXCHANGE_RefundHandle *rh,
                                        &deposit_fee,
                                        &h_wire,
                                        &h_contract_terms,
+                                       &h_age_commitment,
                                        NULL /* h_extensions! */,
                                        &h_denom_pub,
                                        wallet_timestamp,
diff --git a/src/lib/exchange_api_withdraw.c b/src/lib/exchange_api_withdraw.c
index c832699a2..efc8a99c2 100644
--- a/src/lib/exchange_api_withdraw.c
+++ b/src/lib/exchange_api_withdraw.c
@@ -89,6 +89,11 @@ struct TALER_EXCHANGE_WithdrawHandle
   struct TALER_ExchangeWithdrawValues alg_values;
 
   /**
+   * Hash of the age commitment for this coin, if applicable. Maybe NULL
+   */
+  const struct TALER_AgeCommitmentHash *ach;
+
+  /**
    * Denomination key we are withdrawing.
    */
   struct TALER_EXCHANGE_DenomPublicKey pk;
@@ -137,6 +142,7 @@ handle_reserve_withdraw_finished (
                                   blind_sig,
                                   &wh->bks,
                                   &wh->priv,
+                                  wh->ach,
                                   &wh->c_hash,
                                   &wh->alg_values,
                                   &fc))
@@ -222,6 +228,7 @@ withdraw_cs_stage_two_callback (void *cls,
                                 &wh->alg_values,
                                 &wh->bks,
                                 &wh->priv,
+                                wh->ach,
                                 &wh->c_hash,
                                 &wh->pd))
     {
@@ -249,6 +256,7 @@ TALER_EXCHANGE_withdraw (
   const struct TALER_EXCHANGE_DenomPublicKey *pk,
   const struct TALER_ReservePrivateKeyP *reserve_priv,
   const struct TALER_PlanchetMasterSecretP *ps,
+  const struct TALER_AgeCommitmentHash *ach,
   TALER_EXCHANGE_WithdrawCallback res_cb,
   void *res_cb_cls)
 {
@@ -260,6 +268,7 @@ TALER_EXCHANGE_withdraw (
   wh->cb_cls = res_cb_cls;
   wh->reserve_priv = reserve_priv;
   wh->ps = *ps;
+  wh->ach = ach;
   wh->pk = *pk;
   TALER_denom_pub_deep_copy (&wh->pk.key,
                              &pk->key);
@@ -280,6 +289,7 @@ TALER_EXCHANGE_withdraw (
                                   &wh->alg_values,
                                   &wh->bks,
                                   &wh->priv,
+                                  wh->ach,
                                   &wh->c_hash,
                                   &wh->pd))
       {