Merge branch 'age-withdraw', after implementing testing-commands

src/include/taler_exchange_service.h

@@ -1513,6 +1513,11 @@ enum TALER_EXCHANGE_ReserveTransactionType
    */
   TALER_EXCHANGE_RTT_WITHDRAWAL,
 
+  /**
+   * Age-Withdrawal from the reserve.
+   */
+  TALER_EXCHANGE_RTT_AGEWITHDRAWAL,
+
   /**
    * /recoup operation.
    */
@@ -1608,6 +1613,28 @@ struct TALER_EXCHANGE_ReserveHistoryEntry
       struct TALER_Amount fee;
     } withdraw;
 
+    /**
+     * Information about withdraw operation.
+     * @e type is #TALER_EXCHANGE_RTT_AGEWITHDRAWAL.
+     */
+    struct
+    {
+      /**
+       * Signature authorizing the withdrawal for outgoing transaction.
+       */
+      json_t *out_authorization_sig;
+
+      /**
+       * Maximum age commited
+       */
+      uint8_t max_age;
+
+      /**
+       * Fee that was charged for the withdrawal.
+       */
+      struct TALER_Amount fee;
+    } age_withdraw;
+
     /**
      * Information provided if the reserve was filled via /recoup.
      * @e type is #TALER_EXCHANGE_RTT_RECOUP.
@@ -2670,13 +2697,59 @@ struct TALER_EXCHANGE_AgeWithdrawCoinInput
    * The master secret from which we derive all other relevant values for
    * the coin: private key, nonces (if applicable) and age restriction
    */
-  const struct TALER_PlanchetMasterSecretP secrets[TALER_CNC_KAPPA];
+  struct TALER_PlanchetMasterSecretP secrets[TALER_CNC_KAPPA];
 
   /**
    * The denomination of the coin.  Must support age restriction, i.e
    * its .keys.age_mask MUST not be 0
    */
-  const struct TALER_EXCHANGE_DenomPublicKey *denom_pub;
+  struct TALER_EXCHANGE_DenomPublicKey *denom_pub;
+};
+
+
+/**
+ * All the details about a coin that are generated during age-withdrawal and
+ * that may be needed for future operations on the coin.
+ */
+struct TALER_EXCHANGE_AgeWithdrawCoinPrivateDetails
+{
+  /**
+   * Private key of the coin.
+   */
+  struct TALER_CoinSpendPrivateKeyP coin_priv;
+
+  /**
+   * Hash of the public key of the coin.
+   */
+  struct TALER_CoinPubHashP h_coin_pub;
+
+  /**
+   * Value used to blind the key for the signature.
+   * Needed for recoup operations.
+   */
+  union TALER_DenominationBlindingKeyP blinding_key;
+
+  /**
+   * The age commitment, proof for the coin, derived from the
+   * Master secret and maximum age in the originating request
+   */
+  struct TALER_AgeCommitmentProof age_commitment_proof;
+
+  /**
+   * The hash of the age commitment
+   */
+  struct TALER_AgeCommitmentHash h_age_commitment;
+
+  /**
+   * Values contributed from the exchange during the
+   * withdraw protocol.
+   */
+  struct TALER_ExchangeWithdrawValues alg_values;
+
+  /**
+   * The planchet constructed
+   */
+  struct TALER_PlanchetDetail planchet;
 };
 
 /**
@@ -2705,39 +2778,38 @@ struct TALER_EXCHANGE_AgeWithdrawResponse
     struct
     {
       /**
-       * Index that should not be revealed during the age-withdraw reveal phase.
+       * Index that should not be revealed during the age-withdraw reveal
-       * The struct TALER_PlanchetMasterSecretP * from the request
+       * phase.
-       * with this index are the ones to keep.
        */
       uint8_t noreveal_index;
 
       /**
-       * The commitment of the call to /age-withdraw
+       * The commitment of the age-withdraw request, needed for the
+       * subsequent call to /age-withdraw/$ACH/reveal
        */
       struct TALER_AgeWithdrawCommitmentHashP h_commitment;
 
       /**
-       * The algorithm specific values (for CS) need for the coins that were
+       * The number of elements in @e coins, each referring to
-       * retrieved from /csr-withdraw.
+       * TALER_CNC_KAPPA elements
        */
-      struct TALER_ExchangeWithdrawValues *alg_values;
+      size_t num_coins;
 
       /**
-       * Number of elements in @e alg_values, same as number coin candidates.from
+       * The computed details of the non-revealed @e num_coins coins to keep.
-       * the request.
        */
-      size_t num_alg_values;
+      const struct TALER_EXCHANGE_AgeWithdrawCoinPrivateDetails *coin_details;
 
       /**
-       * Signature of the exchange over the origina TALER_AgeWithdrawRequestPS
+       * The array of blinded hashes of the non-revealed
+       * @e num_coins coins, needed for the reveal step;
        */
-      struct TALER_ExchangeSignatureP exchange_sig;
+      const struct TALER_BlindedCoinHashP *blinded_coin_hs;
 
       /**
-       * Key used by the exchange for @e exchange_sig
+       * Key used by the exchange to sign the response.
        */
       struct TALER_ExchangePublicKeyP exchange_pub;
-
     } ok;
   } details;
 };
@@ -2809,7 +2881,6 @@ struct TALER_EXCHANGE_AgeWithdrawBlindedInput
    * Blinded Planchets
    */
   struct TALER_PlanchetDetail planchet_details[TALER_CNC_KAPPA];
-
 };
 
 /**
@@ -2840,19 +2911,16 @@ struct TALER_EXCHANGE_AgeWithdrawBlindedResponse
       uint8_t noreveal_index;
 
       /**
-       * The commitment of the call to /age-withdraw
+       * The commitment of the call to age-withdraw, needed for the subsequent
+       * call to /age-withdraw/$ACH/reveal.
        */
       struct TALER_AgeWithdrawCommitmentHashP h_commitment;
 
       /**
-       * Signature of the exchange over the origina TALER_AgeWithdrawRequestPS
+       * Key used by the exchange to sign the response.
-       */
-      struct TALER_ExchangeSignatureP exchange_sig;
-
-      /**
-       * Key used by the exchange for @e exchange_sig
        */
       struct TALER_ExchangePublicKeyP exchange_pub;
+
     } ok;
   } details;
 
@@ -2959,17 +3027,17 @@ struct TALER_EXCHANGE_AgeWithdrawRevealResponse
     struct
     {
       /**
-       * Number of coins returned.
+       * Number of signatures returned.
        */
-      unsigned int num_coins;
+      unsigned int num_sigs;
 
       /**
-       * Array of @e num_coins values about the coins obtained via the reveal
+       * Array of @e num_coins blinded denomination signatures, giving each
-       * operation.  The array give these coins in the same order (and should
+       * coin its value and validity. The array give these coins in the same
-       * have the same length) in which the original age-withdraw request
+       * order (and should have the same length) in which the original
-       * specified the respective denomination keys.
+       * age-withdraw request specified the respective denomination keys.
        */
-      const struct TALER_EXCHANGE_RevealedCoinInfo *revealed_coins;
+      const struct TALER_BlindedDenominationSignature *blinded_denom_sigs;
 
     } ok;
   } details;
@@ -2994,10 +3062,8 @@ typedef void
  * @param exchange_url The base url of the exchange
  * @param num_coins The number of elements in @e coin_inputs and @e alg_values
  * @param coin_inputs The input for the coins to withdraw, same as in the previous call to /age-withdraw
- * @param alg_values The algorithm specific parameters per coin, from the result to the previous call to /age-withdraw
  * @param noreveal_index The index into each of the kappa coin candidates, that should not be revealed to the exchange
  * @param h_commitment The commmitment from the previous call to /age-withdraw
- * @param max_age maximum age, as used in the to /age-withdraw
  * @param res_cb A callback for the result, maybe NULL
  * @param res_cb_cls A closure for @e res_cb, maybe NULL
  * @return a handle for this request; NULL if the argument was invalid.
@@ -3010,10 +3076,8 @@ TALER_EXCHANGE_age_withdraw_reveal (
   size_t num_coins,
   const struct TALER_EXCHANGE_AgeWithdrawCoinInput coin_inputs[static
                                                                num_coins],
-  const struct TALER_ExchangeWithdrawValues alg_values[static num_coins],
   uint8_t noreveal_index,
   const struct TALER_AgeWithdrawCommitmentHashP *h_commitment,
-  uint8_t max_age,
   TALER_EXCHANGE_AgeWithdrawRevealCallback res_cb,
   void *res_cb_cls);
 
@@ -3034,7 +3098,8 @@ TALER_EXCHANGE_age_withdraw_reveal_cancel (
 /**
  * Information needed to melt (partially spent) coins to obtain fresh coins
  * that are unlinkable to the original coin(s).  Note that melting more than
- * one coin in a single request will make those coins linkable, so we only melt one coin at a time.
+ * one coin in a single request will make those coins linkable, so we only melt
+ * one coin at a time.
  */
 struct TALER_EXCHANGE_RefreshData
 {

src/include/taler_testing_lib.h

@@ -2715,8 +2715,8 @@ TALER_TESTING_get_trait (const struct TALER_TESTING_Trait *traits,
   op (refund_deadline, const struct GNUNET_TIME_Timestamp)              \
   op (exchange_pub, const struct TALER_ExchangePublicKeyP)              \
   op (exchange_sig, const struct TALER_ExchangeSignatureP)              \
-  op (blinding_key, const union TALER_DenominationBlindingKeyP)
+  op (blinding_key, const union TALER_DenominationBlindingKeyP)         \
-
+  op (h_blinded_coin, const struct TALER_BlindedCoinHashP)
 
 TALER_TESTING_SIMPLE_TRAITS (TALER_TESTING_MAKE_DECL_SIMPLE_TRAIT)
 

src/lib/exchange_api_age_withdraw.c

@@ -47,36 +47,9 @@ struct CoinCandidate
   struct TALER_PlanchetMasterSecretP secret;
 
   /**
-   * Age commitment for the coin candidates, calculated from the @e ps and a
+   * The details derived form the master secrets
-   * given maximum age
    */
-  struct TALER_AgeCommitmentProof age_commitment_proof;
+  struct TALER_EXCHANGE_AgeWithdrawCoinPrivateDetails details;
-
-  /**
-   * Age commitment for the coin.
-   */
-  struct TALER_AgeCommitmentHash h_age_commitment;
-
-  /**
-   *  blinding secret
-   */
-  union TALER_DenominationBlindingKeyP blinding_key;
-
-  /**
-   * Private key of the coin we are withdrawing.
-   */
-  struct TALER_CoinSpendPrivateKeyP coin_priv;
-
-  /**
-   * Values of the @cipher selected
-   */
-  struct TALER_ExchangeWithdrawValues alg_values;
-
-  /**
-   * Hash of the public key of the coin we are signing.
-   */
-  struct TALER_CoinPubHashP h_coin_pub;
-
 
   /**
    * Blinded hash of the coin
@@ -340,11 +313,12 @@ reserve_age_withdraw_ok (
     .hr.http_status = MHD_HTTP_OK,
     .details.ok.h_commitment = awbh->h_commitment
   };
+  struct TALER_ExchangeSignatureP exchange_sig;
   struct GNUNET_JSON_Specification spec[] = {
     GNUNET_JSON_spec_uint8 ("noreaveal_index",
                             &response.details.ok.noreveal_index),
     GNUNET_JSON_spec_fixed_auto ("exchange_sig",
-                                 &response.details.ok.exchange_sig),
+                                 &exchange_sig),
     GNUNET_JSON_spec_fixed_auto ("exchange_pub",
                                  &response.details.ok.exchange_pub)
   };
@@ -363,7 +337,7 @@ reserve_age_withdraw_ok (
         &awbh->h_commitment,
         response.details.ok.noreveal_index,
         &response.details.ok.exchange_pub,
-        &response.details.ok.exchange_sig))
+        &exchange_sig))
   {
     GNUNET_break_op (0);
     return GNUNET_SYSERR;
@@ -785,21 +759,26 @@ copy_results (
 {
   struct TALER_EXCHANGE_AgeWithdrawHandle *awh = cls;
   uint8_t idx =  awbr->details.ok.noreveal_index;
-  struct TALER_ExchangeWithdrawValues alg_values[awh->num_coins];
+  struct TALER_EXCHANGE_AgeWithdrawCoinPrivateDetails details[awh->num_coins];
+  struct TALER_BlindedCoinHashP blinded_coin_hs[awh->num_coins];
   struct TALER_EXCHANGE_AgeWithdrawResponse resp = {
     .hr = awbr->hr,
     .details = {
       .ok = { .noreveal_index = awbr->details.ok.noreveal_index,
               .h_commitment = awbr->details.ok.h_commitment,
               .exchange_pub = awbr->details.ok.exchange_pub,
-              .exchange_sig = awbr->details.ok.exchange_sig,
+              .num_coins = awh->num_coins,
-              .num_alg_values = awh->num_coins,
+              .coin_details = details,
-              .alg_values = alg_values},
+              .blinded_coin_hs = blinded_coin_hs},
     },
   };
 
   for (size_t n = 0; n< awh->num_coins; n++)
-    alg_values[n] = awh->coin_data[n].coin_candidates[idx].alg_values;
+  {
+    details[n] = awh->coin_data[n].coin_candidates[idx].details;
+    details[n].planchet = awh->coin_data[n].planchet_details[idx];
+    blinded_coin_hs[n] = awh->coin_data[n].coin_candidates[idx].blinded_coin_h;
+  }
 
   awh->callback (awh->callback_cls,
                  &resp);
@@ -915,23 +894,23 @@ csr_withdraw_done (
     {
       bool success = false;
       /* Complete the initialization of the coin with CS denomination */
-      can->alg_values = csrr->details.ok.alg_values;
+      can->details.alg_values = csrr->details.ok.alg_values;
       TALER_planchet_setup_coin_priv (&can->secret,
-                                      &can->alg_values,
+                                      &can->details.alg_values,
-                                      &can->coin_priv);
+                                      &can->details.coin_priv);
       TALER_planchet_blinding_secret_create (&can->secret,
-                                             &can->alg_values,
+                                             &can->details.alg_values,
-                                             &can->blinding_key);
+                                             &can->details.blinding_key);
       /* This initializes the 2nd half of the
          can->planchet_detail.blinded_planchet! */
       do {
         if (GNUNET_OK !=
             TALER_planchet_prepare (&csr->denom_pub->key,
-                                    &can->alg_values,
+                                    &can->details.alg_values,
-                                    &can->blinding_key,
+                                    &can->details.blinding_key,
-                                    &can->coin_priv,
+                                    &can->details.coin_priv,
-                                    &can->h_age_commitment,
+                                    &can->details.h_age_commitment,
-                                    &can->h_coin_pub,
+                                    &can->details.h_coin_pub,
                                     planchet))
         {
           GNUNET_break (0);
@@ -1029,29 +1008,29 @@ prepare_coins (
                  &can->secret,
                  &input->denom_pub->key.age_mask,
                  awh->max_age,
-                 &can->age_commitment_proof));
+                 &can->details.age_commitment_proof));
 
-      TALER_age_commitment_hash (&can->age_commitment_proof.commitment,
+      TALER_age_commitment_hash (&can->details.age_commitment_proof.commitment,
-                                 &can->h_age_commitment);
+                                 &can->details.h_age_commitment);
 
       switch (input->denom_pub->key.cipher)
       {
       case TALER_DENOMINATION_RSA:
         {
-          can->alg_values.cipher = TALER_DENOMINATION_RSA;
+          can->details.alg_values.cipher = TALER_DENOMINATION_RSA;
           TALER_planchet_setup_coin_priv (&can->secret,
-                                          &can->alg_values,
+                                          &can->details.alg_values,
-                                          &can->coin_priv);
+                                          &can->details.coin_priv);
           TALER_planchet_blinding_secret_create (&can->secret,
-                                                 &can->alg_values,
+                                                 &can->details.alg_values,
-                                                 &can->blinding_key);
+                                                 &can->details.blinding_key);
           FAIL_IF (GNUNET_OK !=
                    TALER_planchet_prepare (&cd->denom_pub.key,
-                                           &can->alg_values,
+                                           &can->details.alg_values,
-                                           &can->blinding_key,
+                                           &can->details.blinding_key,
-                                           &can->coin_priv,
+                                           &can->details.coin_priv,
-                                           &can->h_age_commitment,
+                                           &can->details.h_age_commitment,
-                                           &can->h_coin_pub,
+                                           &can->details.h_coin_pub,
                                            planchet));
           FAIL_IF (GNUNET_OK !=
                    TALER_coin_ev_hash (&planchet->blinded_planchet,

src/lib/exchange_api_age_withdraw_reveal.c

@@ -47,19 +47,12 @@ struct TALER_EXCHANGE_AgeWithdrawRevealHandle
   /* The age-withdraw commitment */
   struct TALER_AgeWithdrawCommitmentHashP h_commitment;
 
-  /* The maximum age */
-  uint8_t max_age;
-
   /* Number of coins */
   size_t num_coins;
 
   /* The @e num_coins * kappa coin secrets from the age-withdraw commitment */
   const struct TALER_EXCHANGE_AgeWithdrawCoinInput *coins_input;
 
-  /* The @e num_coins algorithm- and coin-specific parameters from the
-   * previous call to /age-withdraw. */
-  const struct TALER_ExchangeWithdrawValues *alg_values;
-
   /* The url for the reveal request */
   const char *request_url;
 
@@ -81,82 +74,6 @@ struct TALER_EXCHANGE_AgeWithdrawRevealHandle
 };
 
 
-static enum GNUNET_GenericReturnValue
-reveal_coin (
-  const struct TALER_PlanchetMasterSecretP *secret,
-  const struct TALER_DenominationPublicKey *denom_pub,
-  const struct TALER_ExchangeWithdrawValues *alg_values,
-  const struct TALER_BlindedDenominationSignature *blind_sig,
-  uint8_t max_age,
-  struct TALER_EXCHANGE_RevealedCoinInfo *revealed_coin)
-{
-  enum GNUNET_GenericReturnValue ret = GNUNET_SYSERR;
-
-#define BREAK_ON_FAILURE(call) \
-  do { \
-    if (GNUNET_OK != (call)) { GNUNET_break (0); break; } \
-  } while(0)
-
-  do {
-    struct TALER_CoinPubHashP h_coin_pub;
-    struct TALER_PlanchetDetail planchet_detail;
-    const struct TALER_AgeCommitmentHash *hac = NULL;
-    struct TALER_FreshCoin fresh_coin;
-
-    TALER_planchet_setup_coin_priv (secret,
-                                    alg_values,
-                                    &revealed_coin->coin_priv);
-
-    TALER_planchet_blinding_secret_create (secret,
-                                           alg_values,
-                                           &revealed_coin->bks);
-
-    revealed_coin->age_commitment_proof = NULL;
-    if (0 < max_age)
-    {
-      BREAK_ON_FAILURE (
-        TALER_age_restriction_from_secret (
-          secret,
-          &denom_pub->age_mask,
-          max_age,
-          revealed_coin->age_commitment_proof));
-
-      TALER_age_commitment_hash (
-        &revealed_coin->age_commitment_proof->commitment,
-        &revealed_coin->h_age_commitment);
-
-      hac = &revealed_coin->h_age_commitment;
-    }
-
-    BREAK_ON_FAILURE (
-      TALER_planchet_prepare (denom_pub,
-                              alg_values,
-                              &revealed_coin->bks,
-                              &revealed_coin->coin_priv,
-                              hac,
-                              &h_coin_pub,
-                              &planchet_detail));
-
-    BREAK_ON_FAILURE (
-      TALER_planchet_to_coin (denom_pub,
-                              blind_sig,
-                              &revealed_coin->bks,
-                              &revealed_coin->coin_priv,
-                              &revealed_coin->h_age_commitment,
-                              &h_coin_pub,
-                              alg_values,
-                              &fresh_coin));
-
-    /* success */
-    revealed_coin->sig = fresh_coin.sig;
-    ret = GNUNET_OK;
-  } while(0);
-
-  return ret;
-#undef BREAK_ON_FAILURE
-}
-
-
 /**
  * We got a 200 OK response for the /age-withdraw/$ACH/reveal operation.
  * Extract the signed blindedcoins and return it to the caller.
@@ -197,16 +114,14 @@ age_withdraw_reveal_ok (
   }
 
   {
-    struct TALER_EXCHANGE_RevealedCoinInfo revealed_coins[awrh->num_coins];
+    struct TALER_BlindedDenominationSignature denom_sigs[awrh->num_coins];
 
     /* Reconstruct the coins and unblind the signatures */
     for (size_t n = 0; n < awrh->num_coins; n++)
     {
-      enum GNUNET_GenericReturnValue ret;
-      struct TALER_BlindedDenominationSignature blinded_sig;
       json_t *j_sig = json_array_get (j_sigs, n);
       struct GNUNET_JSON_Specification spec[] = {
-        GNUNET_JSON_spec_fixed_auto ("", &blinded_sig),
+        GNUNET_JSON_spec_fixed_auto ("", &denom_sigs[n]),
         GNUNET_JSON_spec_end ()
       };
 
@@ -218,19 +133,10 @@ age_withdraw_reveal_ok (
         GNUNET_break_op (0);
         return GNUNET_SYSERR;
       }
-      ret = reveal_coin (&awrh->coins_input[n].secrets[awrh->noreveal_index],
-                         &awrh->coins_input[n].denom_pub->key,
-                         &awrh->alg_values[n],
-                         &blinded_sig,
-                         awrh->max_age,
-                         &revealed_coins[n]);
-
-      if (GNUNET_OK != ret)
-        return ret;
     }
 
-    response.details.ok.num_coins = awrh->num_coins;
+    response.details.ok.num_sigs = awrh->num_coins;
-    response.details.ok.revealed_coins = revealed_coins;
+    response.details.ok.blinded_denom_sigs = denom_sigs;
     awrh->callback (awrh->callback_cls,
                     &response);
     /* Make sure the callback isn't called again */
@@ -510,24 +416,19 @@ TALER_EXCHANGE_age_withdraw_reveal (
   size_t num_coins,
   const struct TALER_EXCHANGE_AgeWithdrawCoinInput coins_input[static
                                                                num_coins],
-  const struct TALER_ExchangeWithdrawValues alg_values[static num_coins],
   uint8_t noreveal_index,
   const struct TALER_AgeWithdrawCommitmentHashP *h_commitment,
-  uint8_t max_age,
   TALER_EXCHANGE_AgeWithdrawRevealCallback reveal_cb,
   void *reveal_cb_cls)
 {
   struct TALER_EXCHANGE_AgeWithdrawRevealHandle *awrh =
     GNUNET_new (struct TALER_EXCHANGE_AgeWithdrawRevealHandle);
   awrh->noreveal_index = noreveal_index;
-  awrh->callback = reveal_cb;
-  awrh->callback_cls = reveal_cb_cls;
   awrh->h_commitment = *h_commitment;
   awrh->num_coins = num_coins;
   awrh->coins_input = coins_input;
-  awrh->alg_values = alg_values;
+  awrh->callback = reveal_cb;
-  awrh->max_age = max_age;
+  awrh->callback_cls = reveal_cb_cls;
-
 
   if (GNUNET_OK !=
       prepare_url (exchange_url,

src/lib/exchange_api_common.c

@@ -765,6 +765,8 @@ TALER_EXCHANGE_free_reserve_history (
       break;
     case TALER_EXCHANGE_RTT_WITHDRAWAL:
       break;
+    case TALER_EXCHANGE_RTT_AGEWITHDRAWAL:
+      break;
     case TALER_EXCHANGE_RTT_RECOUP:
       break;
     case TALER_EXCHANGE_RTT_CLOSING:

src/lib/notizen.md

@@ -0,0 +1,236 @@
+# Notes re: planchets and blinding
+
+## `TALER_denom_blind()`
+
+```
+Blind coin for blind signing with @a dk using blinding secret @a coin_bks.
+```
+
+- `@param[out] c_hash resulting hashed coin`
+- `@param[out] blinded_planchet planchet data to initialize`
+
+## `TALER_planchet_prepare()`
+
+Prepare a planchet for withdrawal.  Creates and blinds a coin.
+
+- calls `TALER_denom_blind()!`
+- `@param[out] c_hash set to the hash of the public key of the coin (needed later)`
+- `@param[out] pd set to the planchet detail for TALER_MERCHANT_tip_pickup() and other withdraw operations, pd->blinded_planchet.cipher will be set to cipher from @a dk`
+
+
+## `TALER_coin_ev_hash`
+
+Compute the hash of a blinded coin.
+
+- `@param blinded_planchet blinded planchet`
+- `@param denom_hash hash of the denomination publick key`
+- `@param[out] bch where to write the hash, type struct TALER_BlindedCoinHashP`
+
+**Where is this called!?**
+
+```
+taler-exchange-httpd_refreshes_reveal.c
+605:    TALER_coin_ev_hash (&rrc->blinded_planchet,
+
+taler-exchange-httpd_recoup.c
+290:        TALER_coin_ev_hash (&blinded_planchet,
+
+taler-exchange-httpd_withdraw.c
+581:      TALER_coin_ev_hash (&wc.blinded_planchet,
+
+taler-exchange-httpd_age-withdraw_reveal.c
+350:    ret = TALER_coin_ev_hash (&detail.blinded_planchet,
+
+taler-exchange-httpd_recoup-refresh.c
+284:    TALER_coin_ev_hash (&blinded_planchet,
+
+taler-exchange-httpd_age-withdraw.c
+279:      ret = TALER_coin_ev_hash (&awc->coin_evs[c],
+884:    TALER_coin_ev_hash (&awc->coin_evs[i],
+
+taler-exchange-httpd_batch-withdraw.c
+832:        TALER_coin_ev_hash (&pc->blinded_planchet,
+```
+
+
+## `TALER_coin_pub_hash`
+
+Compute the hash of a coin.
+
+- `@param coin_pub public key of the coin`
+- `@param age_commitment_hash hash of the age commitment vector. NULL, if no age commitment was set`
+- `@param[out] coin_h where to write the hash`
+
+**Where is this called!?**
+
+### In `lib/crypto.c`, function `TALER_test_coin_valid`.
+
+```
+Check if a coin is valid; that is, whether the denomination key
+exists, is not expired, and the signature is correct.
+
+@param coin_public_info the coin public info to check for validity
+@param denom_pub denomination key, must match @a coin_public_info's `denom_pub_hash`
+@return #GNUNET_YES if the coin is valid,
+        #GNUNET_NO if it is invalid
+        #GNUNET_SYSERR if an internal error occurred
+```
+
+It then calls `TALER_denom_pub_verify` on the result of `TALER_coin_pub_hash` and the signature
+
+
+### In `util/denom.c`, function `TALER_denom_blind`
+
+## `TALER_EXCHANGE_batch_withdraw` vs `TALER_EXCHANGE_batch_withdraw2`
+
+### `TALER_EXCHANGE_batch_withdraw`
+
+```
+/**
+ * Withdraw multiple coins from the exchange using a /reserves/$RESERVE_PUB/batch-withdraw
+ * request.  This API is typically used by a wallet to withdraw many coins from a
+ * reserve.
+ *
+ * Note that to ensure that no money is lost in case of hardware
+ * failures, the caller must have committed (most of) the arguments to
+ * disk before calling, and be ready to repeat the request with the
+ * same arguments in case of failures.
+ *
+ * @param curl_ctx The curl context to use
+ * @param exchange_url The base-URL of the exchange
+ * @param keys The /keys material from the exchange
+ * @param reserve_priv private key of the reserve to withdraw from
+ * @param wci_length number of entries in @a wcis
+ * @param wcis inputs that determine the planchets
+ * @param res_cb the callback to call when the final result for this request is available
+ * @param res_cb_cls closure for @a res_cb
+ * @return NULL
+ *         if the inputs are invalid (i.e. denomination key not with this exchange).
+ *         In this case, the callback is not called.
+ */
+struct TALER_EXCHANGE_BatchWithdrawHandle *
+TALER_EXCHANGE_batch_withdraw (
+  struct GNUNET_CURL_Context *curl_ctx,
+  const char *exchange_url,
+  const struct TALER_EXCHANGE_Keys *keys,
+  const struct TALER_ReservePrivateKeyP *reserve_priv,
+  unsigned int wci_length,
+  const struct TALER_EXCHANGE_WithdrawCoinInput wcis[static wci_length],
+  TALER_EXCHANGE_BatchWithdrawCallback res_cb,
+  void *res_cb_cls);
+```
+
+### `TALER_EXCHANGE_batch_withdraw2`
+
+```
+/**
+ * Withdraw a coin from the exchange using a /reserves/$RESERVE_PUB/batch-withdraw
+ * request.  This API is typically used by a merchant to withdraw a tip
+ * where the blinding factor is unknown to the merchant.
+ *
+ * Note that to ensure that no money is lost in case of hardware
+ * failures, the caller must have committed (most of) the arguments to
+ * disk before calling, and be ready to repeat the request with the
+ * same arguments in case of failures.
+ *
+ * @param curl_ctx The curl context to use
+ * @param exchange_url The base-URL of the exchange
+ * @param keys The /keys material from the exchange
+ * @param pds array of planchet details of the planchet to withdraw
+ * @param pds_length number of entries in the @a pds array
+ * @param reserve_priv private key of the reserve to withdraw from
+ * @param res_cb the callback to call when the final result for this request is available
+ * @param res_cb_cls closure for @a res_cb
+ * @return NULL
+ *         if the inputs are invalid (i.e. denomination key not with this exchange).
+ *         In this case, the callback is not called.
+ */
+struct TALER_EXCHANGE_BatchWithdraw2Handle *
+TALER_EXCHANGE_batch_withdraw2 (
+  struct GNUNET_CURL_Context *curl_ctx,
+  const char *exchange_url,
+  const struct TALER_EXCHANGE_Keys *keys,
+  const struct TALER_ReservePrivateKeyP *reserve_priv,
+  unsigned int pds_length,
+  const struct TALER_PlanchetDetail pds[static pds_length],
+  TALER_EXCHANGE_BatchWithdraw2Callback res_cb,
+  void *res_cb_cls);
+```
+
+### Differences
+
+| batch_withdraw                     | batch_withdraw2        |
+|------------------------------------|------------------------|
+| `TALER_EXCHANGE_WithdrawCoinInput` | `TALER_PlanchetDetail` |
+
+
+```
+struct TALER_EXCHANGE_WithdrawCoinInput
+{
+  /**
+   * Denomination of the coin.
+   */
+  const struct TALER_EXCHANGE_DenomPublicKey *pk;
+
+  /**
+   * Master key material for the coin.
+   */
+  const struct TALER_PlanchetMasterSecretP *ps;
+
+  /**
+   * Age commitment for the coin.
+   */
+  const struct TALER_AgeCommitmentHash *ach;
+
+};
+```
+
+
+```
+struct TALER_PlanchetDetail
+{
+  /**
+   * Hash of the denomination public key.
+   */
+  struct TALER_DenominationHashP denom_pub_hash;
+
+  /**
+   * The blinded planchet
+   */
+  struct TALER_BlindedPlanchet {
+      /**
+       * Type of the sign blinded message
+       */
+      enum TALER_DenominationCipher cipher;
+
+      /**
+       * Details, depending on @e cipher.
+       */
+      union
+      {
+        /**
+         * If we use #TALER_DENOMINATION_CS in @a cipher.
+         */
+        struct TALER_BlindedCsPlanchet cs_blinded_planchet;
+
+        /**
+         * If we use #TALER_DENOMINATION_RSA in @a cipher.
+         */
+        struct TALER_BlindedRsaPlanchet rsa_blinded_planchet;
+
+      } details;
+  } blinded_planchet;
+};
+
+```
+
+
+
+## TODOs
+
+### Update documentation
+
+- [x] batch-withdraw needs error code for AgeRestrictionRequired
+- [x] withdraw needs error code for AgeRestrictionRequired
+
+

src/testing/Makefile.am

@@ -40,6 +40,7 @@ libtalertesting_la_LDFLAGS = \
   -version-info 0:0:0 \
   -no-undefined
 libtalertesting_la_SOURCES = \
+  testing_api_cmd_age_withdraw.c \
   testing_api_cmd_auditor_add_denom_sig.c \
   testing_api_cmd_auditor_add.c \
   testing_api_cmd_auditor_del.c \

src/testing/testing_api_cmd_age_withdraw.c

@@ -23,20 +23,76 @@
  */
 
 #include "platform.h"
+#include "taler_exchange_service.h"
 #include "taler_json_lib.h"
+#include <gnunet/gnunet_common.h>
 #include <microhttpd.h>
 #include <gnunet/gnunet_curl_lib.h>
 #include "taler_signatures.h"
 #include "taler_extensions.h"
 #include "taler_testing_lib.h"
 
+/*
+ * The output state of coin
+ */
+struct CoinOutputState
+{
+
+  /**
+   * The calculated details during "age-withdraw", for the selected coin.
+   */
+  struct TALER_EXCHANGE_AgeWithdrawCoinPrivateDetails details;
+
+  /**
+   * The (wanted) value of the coin, MUST be the same as input.denom_pub.value;
+   */
+  struct TALER_Amount amount;
+
+  /**
+   * Reserve history entry that corresponds to this coin.
+   * Will be of type #TALER_EXCHANGE_RTT_AGEWITHDRAWAL.
+   */
+  struct TALER_EXCHANGE_ReserveHistoryEntry reserve_history;
+};
+
 /**
  * State for a "age withdraw" CMD:
  */
 
 struct AgeWithdrawState
 {
-  /*
+
+  /**
+   * Interpreter state (during command)
+   */
+  struct TALER_TESTING_Interpreter *is;
+
+  /**
+   * The age-withdraw handle
+   */
+  struct TALER_EXCHANGE_AgeWithdrawHandle *handle;
+
+  /**
+   * Exchange base URL.  Only used as offered trait.
+   */
+  char *exchange_url;
+
+  /**
+   * URI of the reserve we are withdrawing from.
+   */
+  char *reserve_payto_uri;
+
+  /**
+   * Private key of the reserve we are withdrawing from.
+   */
+  struct TALER_ReservePrivateKeyP reserve_priv;
+
+  /**
+   * Public key of the reserve we are withdrawing from.
+   */
+  struct TALER_ReservePublicKeyP reserve_pub;
+
+  /**
    * Which reserve should we withdraw from?
    */
   const char *reserve_reference;
@@ -46,6 +102,11 @@ struct AgeWithdrawState
    */
   unsigned int expected_response_code;
 
+  /**
+   * Age mask
+   */
+  struct TALER_AgeMask mask;
+
   /**
    * The maximum age we commit to
    */
@@ -55,8 +116,338 @@ struct AgeWithdrawState
    * Number of coins to withdraw
    */
   size_t num_coins;
+
+  /**
+   * The @e num_coins input that is provided to the
+   * `TALER_EXCHANGE_age_withdraw` API.
+   * Each contains kappa secrets, from which we will have
+   * to disclose kappa-1 in a subsequent age-withdraw-reveal operation.
+   */
+  struct TALER_EXCHANGE_AgeWithdrawCoinInput *coin_inputs;
+
+  /**
+   * The output state of @e num_coins coins, calculated during the
+   * "age-withdraw" operation.
+   */
+  struct CoinOutputState *coin_outputs;
+
+  /**
+   * The index returned by the exchange for the "age-withdraw" operation,
+   * of the kappa coin candidates that we do not disclose and keep.
+   */
+  uint8_t noreveal_index;
+
+  /**
+   * The blinded hashes of the non-revealed (to keep) @e num_coins coins.
+   */
+  const struct TALER_BlindedCoinHashP *blinded_coin_hs;
+
+  /**
+   * The hash of the commitment, needed for the reveal step.
+   */
+  struct TALER_AgeWithdrawCommitmentHashP h_commitment;
+
+  /**
+   * Set to the KYC requirement payto hash *if* the exchange replied with a
+   * request for KYC.
+   */
+  struct TALER_PaytoHashP h_payto;
+
+  /**
+   * Set to the KYC requirement row *if* the exchange replied with
+   * a request for KYC.
+   */
+  uint64_t requirement_row;
+
 };
 
+/**
+ * Callback for the "age-withdraw" ooperation;  It checks that the response
+ * code is expected and store the exchange signature in the state.
+ *
+ * @param cls Closure of type `struct AgeWithdrawState *`
+ * @param awr Repsonse details
+ */
+static void
+age_withdraw_cb (
+  void *cls,
+  const struct TALER_EXCHANGE_AgeWithdrawResponse *response)
+{
+  struct AgeWithdrawState *aws = cls;
+  struct TALER_TESTING_Interpreter *is = aws->is;
+
+  aws->handle = NULL;
+  if (aws->expected_response_code != response->hr.http_status)
+  {
+    TALER_TESTING_unexpected_status_with_body (is,
+                                               response->hr.http_status,
+                                               aws->expected_response_code,
+                                               response->hr.reply);
+    return;
+  }
+
+  switch (response->hr.http_status)
+  {
+  case MHD_HTTP_OK:
+    aws->noreveal_index = response->details.ok.noreveal_index;
+    aws->h_commitment = response->details.ok.h_commitment;
+
+    GNUNET_assert (aws->num_coins == response->details.ok.num_coins);
+    for (size_t n = 0; n < aws->num_coins; n++)
+    {
+      aws->coin_outputs[n].details = response->details.ok.coin_details[n];
+      TALER_age_commitment_proof_deep_copy (
+        &response->details.ok.coin_details[n].age_commitment_proof,
+        &aws->coin_outputs[n].details.age_commitment_proof);
+    }
+    aws->blinded_coin_hs = response->details.ok.blinded_coin_hs;
+    break;
+  case MHD_HTTP_FORBIDDEN:
+  case MHD_HTTP_NOT_FOUND:
+  case MHD_HTTP_GONE:
+    /* nothing to check */
+    break;
+  case MHD_HTTP_CONFLICT:
+    /* TODO[oec]: Add this to the response-type and handle it here */
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "Age withdraw test command does not YET support status code %u\n",
+                response->hr.http_status);
+    break;
+  case MHD_HTTP_UNAVAILABLE_FOR_LEGAL_REASONS:
+    /* TODO[oec]: Add this to response-type and handle it here  */
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "Age withdraw test command does not YET support status code %u\n",
+                response->hr.http_status);
+    break;
+  default:
+    /* Unsupported status code (by test harness) */
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "Age withdraw test command does not support status code %u\n",
+                response->hr.http_status);
+    GNUNET_break (0);
+    break;
+  }
+
+  /* We are done with this command, pick the next one */
+  TALER_TESTING_interpreter_next (is);
+}
+
+
+/**
+ * Run the command for age-withdraw.
+ */
+static void
+age_withdraw_run (
+  void *cls,
+  const struct TALER_TESTING_Command *cmd,
+  struct TALER_TESTING_Interpreter *is)
+{
+  struct AgeWithdrawState *aws = cls;
+  struct TALER_EXCHANGE_Keys *keys = TALER_TESTING_get_keys (is);
+  const struct TALER_ReservePrivateKeyP *rp;
+  const struct TALER_TESTING_Command *create_reserve;
+  const struct TALER_EXCHANGE_DenomPublicKey *dpk;
+
+  aws->is = is;
+
+  /* Prepare the reserve related data */
+  create_reserve
+    = TALER_TESTING_interpreter_lookup_command (
+        is,
+        aws->reserve_reference);
+
+  if (NULL == create_reserve)
+  {
+    GNUNET_break (0);
+    TALER_TESTING_interpreter_fail (is);
+    return;
+  }
+  if (GNUNET_OK !=
+      TALER_TESTING_get_trait_reserve_priv (create_reserve,
+                                            &rp))
+  {
+    GNUNET_break (0);
+    TALER_TESTING_interpreter_fail (is);
+    return;
+  }
+  if (NULL == aws->exchange_url)
+    aws->exchange_url
+      = GNUNET_strdup (TALER_TESTING_get_exchange_url (is));
+  aws->reserve_priv = *rp;
+  GNUNET_CRYPTO_eddsa_key_get_public (&aws->reserve_priv.eddsa_priv,
+                                      &aws->reserve_pub.eddsa_pub);
+  aws->reserve_payto_uri
+    = TALER_reserve_make_payto (aws->exchange_url,
+                                &aws->reserve_pub);
+
+  aws->coin_inputs = GNUNET_new_array (
+    aws->num_coins,
+    struct TALER_EXCHANGE_AgeWithdrawCoinInput);
+
+  for (unsigned int i = 0; i<aws->num_coins; i++)
+  {
+    struct TALER_EXCHANGE_AgeWithdrawCoinInput *input = &aws->coin_inputs[i];
+    struct CoinOutputState *cos = &aws->coin_outputs[i];
+
+    /* randomly create the secrets for the kappa coin-candidates */
+    GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_WEAK,
+                                &input->secrets,
+                                sizeof(input->secrets));
+    /* Find denomination */
+    dpk = TALER_TESTING_find_pk (keys,
+                                 &cos->amount,
+                                 true); /* _always_ use denominations with age-striction */
+    if (NULL == dpk)
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  "Failed to determine denomination key at %s\n",
+                  (NULL != cmd) ? cmd->label : "<retried command>");
+      GNUNET_break (0);
+      TALER_TESTING_interpreter_fail (is);
+      return;
+    }
+    /* We copy the denomination key, as re-querying /keys
+     * would free the old one. */
+    input->denom_pub = TALER_EXCHANGE_copy_denomination_key (dpk);
+    cos->reserve_history.type = TALER_EXCHANGE_RTT_AGEWITHDRAWAL;
+    GNUNET_assert (0 <=
+                   TALER_amount_add (&cos->reserve_history.amount,
+                                     &cos->amount,
+                                     &input->denom_pub->fees.withdraw));
+    cos->reserve_history.details.withdraw.fee = input->denom_pub->fees.withdraw;
+  }
+
+  /* Execute the age-withdraw protocol */
+  aws->handle =
+    TALER_EXCHANGE_age_withdraw (
+      TALER_TESTING_interpreter_get_context (is),
+      keys,
+      TALER_TESTING_get_exchange_url (is),
+      rp,
+      aws->num_coins,
+      aws->coin_inputs,
+      aws->max_age,
+      &age_withdraw_cb,
+      aws);
+
+  if (NULL == aws->handle)
+  {
+    GNUNET_break (0);
+    TALER_TESTING_interpreter_fail (is);
+    return;
+  }
+}
+
+
+/**
+ * Free the state of a "age withdraw" CMD, and possibly cancel a
+ * pending operation thereof
+ *
+ * @param cls Closure of type `struct AgeWithdrawState`
+ * @param cmd The command beeing freed.
+ */
+static void
+age_withdraw_cleanup (
+  void *cls,
+  const struct TALER_TESTING_Command *cmd)
+{
+  struct AgeWithdrawState *aws = cls;
+
+  if (NULL != aws->handle)
+  {
+    TALER_TESTING_command_incomplete (aws->is,
+                                      cmd->label);
+    TALER_EXCHANGE_age_withdraw_cancel (aws->handle);
+    aws->handle = NULL;
+  }
+
+  for (size_t n = 0; n < aws->num_coins; n++)
+  {
+    struct TALER_EXCHANGE_AgeWithdrawCoinInput *in = &aws->coin_inputs[n];
+    struct CoinOutputState *out = &aws->coin_outputs[n];
+
+    if (NULL != in->denom_pub)
+    {
+      TALER_EXCHANGE_destroy_denomination_key (in->denom_pub);
+      in->denom_pub = NULL;
+    }
+    TALER_age_commitment_proof_free (&out->details.age_commitment_proof);
+  }
+  GNUNET_free (aws->coin_inputs);
+  GNUNET_free (aws->coin_outputs);
+  GNUNET_free (aws->exchange_url);
+  GNUNET_free (aws->reserve_payto_uri);
+  GNUNET_free (aws);
+}
+
+
+/**
+ * Offer internal data of a "age withdraw" CMD state to other commands.
+ *
+ * @param cls Closure of type `struct AgeWithdrawState`
+ * @param[out] ret result (could be anything)
+ * @param trait name of the trait
+ * @param idx index number of the object to offer.
+ * @return #GNUNET_OK on success
+ */
+static enum GNUNET_GenericReturnValue
+age_withdraw_traits (
+  void *cls,
+  const void **ret,
+  const char *trait,
+  unsigned int idx)
+{
+  struct AgeWithdrawState *aws = cls;
+  uint8_t k = aws->noreveal_index;
+  struct TALER_EXCHANGE_AgeWithdrawCoinInput *in = &aws->coin_inputs[idx];
+  struct CoinOutputState *out = &aws->coin_outputs[idx];
+  struct TALER_EXCHANGE_AgeWithdrawCoinPrivateDetails *details =
+    &aws->coin_outputs[idx].details;
+  struct TALER_TESTING_Trait traits[] = {
+    /* history entry MUST be first due to response code logic below! */
+    TALER_TESTING_make_trait_reserve_history (idx,
+                                              &out->reserve_history),
+    TALER_TESTING_make_trait_denom_pub (idx,
+                                        in->denom_pub),
+    TALER_TESTING_make_trait_reserve_priv (&aws->reserve_priv),
+    TALER_TESTING_make_trait_reserve_pub (&aws->reserve_pub),
+    TALER_TESTING_make_trait_amounts (idx,
+                                      &out->amount),
+    /* TODO[oec]: add legal requirement to response and handle it here, as well
+    TALER_TESTING_make_trait_legi_requirement_row (&aws->requirement_row),
+    TALER_TESTING_make_trait_h_payto (&aws->h_payto),
+    */
+    TALER_TESTING_make_trait_h_blinded_coin (idx,
+                                             &aws->blinded_coin_hs[idx]),
+    TALER_TESTING_make_trait_payto_uri (aws->reserve_payto_uri),
+    TALER_TESTING_make_trait_exchange_url (aws->exchange_url),
+    TALER_TESTING_make_trait_coin_priv (idx,
+                                        &details->coin_priv),
+    TALER_TESTING_make_trait_planchet_secrets (idx,
+                                               &in->secrets[k]),
+    TALER_TESTING_make_trait_blinding_key (idx,
+                                           &details->blinding_key),
+    TALER_TESTING_make_trait_exchange_wd_value (idx,
+                                                &details->alg_values),
+    TALER_TESTING_make_trait_age_commitment_proof (
+      idx,
+      &details->age_commitment_proof),
+    TALER_TESTING_make_trait_h_age_commitment (
+      idx,
+      &details->h_age_commitment),
+  };
+
+  if (idx >= aws->num_coins)
+    return GNUNET_NO;
+
+  return TALER_TESTING_get_trait ((aws->expected_response_code == MHD_HTTP_OK)
+                                  ? &traits[0] /* we have reserve history */
+                                  : &traits[1], /* skip reserve history */
+                                  ret,
+                                  trait,
+                                  idx);
+}
+
 
 struct TALER_TESTING_Command
 TALER_TESTING_cmd_age_withdraw (const char *label,
@@ -71,60 +462,27 @@ TALER_TESTING_cmd_age_withdraw (const char *label,
   va_list ap;
 
   aws = GNUNET_new (struct AgeWithdrawState);
-  aws->max_age = max_age;
   aws->reserve_reference = reserve_reference;
   aws->expected_response_code = expected_response_code;
+  aws->mask = TALER_extensions_get_age_restriction_mask ();
+  aws->max_age = TALER_get_lowest_age (&aws->mask, max_age);
 
   cnt = 1;
   va_start (ap, amount);
   while (NULL != (va_arg (ap, const char *)))
     cnt++;
   aws->num_coins = cnt;
-  aws->coins = GNUNET_new_array (cnt,
+  aws->coin_outputs = GNUNET_new_array (cnt,
-                                 struct CoinState);
+                                        struct CoinOutputState);
   va_end (ap);
   va_start (ap, amount);
-  for (unsigned int i = 0; i<ws->num_coins; i++)
+
+  for (unsigned int i = 0; i<aws->num_coins; i++)
   {
-    struct CoinState *cs = &ws->coins[i];
+    struct CoinOutputState *out = &aws->coin_outputs[i];
-
-    if (0 < age)
-    {
-      struct TALER_AgeCommitmentProof *acp;
-      struct TALER_AgeCommitmentHash *hac;
-      struct GNUNET_HashCode seed;
-      struct TALER_AgeMask mask;
-
-      acp = GNUNET_new (struct TALER_AgeCommitmentProof);
-      hac = GNUNET_new (struct TALER_AgeCommitmentHash);
-      mask = TALER_extensions_get_age_restriction_mask ();
-      GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_WEAK,
-                                  &seed,
-                                  sizeof(seed));
-
-      if (GNUNET_OK !=
-          TALER_age_restriction_commit (
-            &mask,
-            age,
-            &seed,
-            acp))
-      {
-        GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                    "Failed to generate age commitment for age %d at %s\n",
-                    age,
-                    label);
-        GNUNET_assert (0);
-      }
-
-      TALER_age_commitment_hash (&acp->commitment,
-                                 hac);
-      cs->age_commitment_proof = acp;
-      cs->h_age_commitment = hac;
-    }
-
     if (GNUNET_OK !=
         TALER_string_to_amount (amount,
-                                &cs->amount))
+                                &out->amount))
     {
       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                   "Failed to parse amount `%s' at %s\n",
@@ -132,19 +490,20 @@ TALER_TESTING_cmd_age_withdraw (const char *label,
                   label);
       GNUNET_assert (0);
     }
-    /* move on to next vararg! */
-    amount = va_arg (ap, const char *);
   }
+
+  /* move on to next vararg! */
+  amount = va_arg (ap, const char *);
   GNUNET_assert (NULL == amount);
   va_end (ap);
 
   {
     struct TALER_TESTING_Command cmd = {
-      .cls = ws,
+      .cls = aws,
       .label = label,
       .run = &age_withdraw_run,
       .cleanup = &age_withdraw_cleanup,
-      .traits = &age_withdraw_traits
+      .traits = &age_withdraw_traits,
     };
 
     return cmd;
@@ -152,4 +511,237 @@ TALER_TESTING_cmd_age_withdraw (const char *label,
 }
 
 
+/**
+ * The state for the age-withdraw-reveal operation
+ */
+struct AgeWithdrawRevealState
+{
+  /**
+   * The reference to the CMD resembling the previous call to age-withdraw
+   */
+  const char *age_withdraw_reference;
+
+  /**
+   * The state to the previous age-withdraw command
+   */
+  const struct AgeWithdrawState *aws;
+
+  /**
+   * The expected response code from the call to the
+   * age-withdraw-reveal operation
+   */
+  unsigned int expected_response_code;
+
+  /**
+   * Interpreter state (during command)
+   */
+  struct TALER_TESTING_Interpreter *is;
+
+  /**
+   * The handle to the reveal-operation
+   */
+  struct TALER_EXCHANGE_AgeWithdrawRevealHandle *handle;
+
+
+  /**
+   * Number of coins, extracted form the age withdraw command
+   */
+  size_t num_coins;
+
+  /**
+   * The signatures of the @e num_coins coins returned
+   */
+  struct TALER_DenominationSignature *denom_sigs;
+
+};
+
+/*
+ * Callback for the reveal response
+ *
+ * @param cls Closure of type `struct AgeWithdrawRevealState`
+ * @param awr The response
+ */
+static void
+age_withdraw_reveal_cb (
+  void *cls,
+  const struct TALER_EXCHANGE_AgeWithdrawRevealResponse *response)
+{
+  struct AgeWithdrawRevealState *awrs = cls;
+  struct TALER_TESTING_Interpreter *is = awrs->is;
+
+  awrs->handle = NULL;
+  if (awrs->expected_response_code != response->hr.http_status)
+  {
+    TALER_TESTING_unexpected_status_with_body (is,
+                                               response->hr.http_status,
+                                               awrs->expected_response_code,
+                                               response->hr.reply);
+    return;
+  }
+  switch (response->hr.http_status)
+  {
+  case MHD_HTTP_OK:
+    {
+      const struct AgeWithdrawState *aws = awrs->aws;
+      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                  "Got age-withdraw reveal success!\n");
+      GNUNET_assert (awrs->num_coins == response->details.ok.num_sigs);
+      for (size_t n = 0; n < awrs->num_coins; n++)
+        TALER_denom_sig_unblind (&awrs->denom_sigs[n],
+                                 &response->details.ok.blinded_denom_sigs[n],
+                                 &aws->coin_outputs[n].details.blinding_key,
+                                 &aws->coin_outputs[n].details.h_coin_pub,
+                                 &aws->coin_outputs[n].details.alg_values,
+                                 &aws->coin_inputs[n].denom_pub->key);
+    }
+    break;
+  case MHD_HTTP_NOT_FOUND:
+  case MHD_HTTP_FORBIDDEN:
+    /* nothing to check */
+    break;
+  /* TODO[oec]: handle more cases !? */
+  default:
+    /* Unsupported status code (by test harness) */
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "Age withdraw reveal test command does not support status code %u\n",
+                response->hr.http_status);
+    GNUNET_break (0);
+    break;
+  }
+
+  /* We are done with this command, pick the next one */
+  TALER_TESTING_interpreter_next (is);
+}
+
+
+/**
+ * Run the command for age-withdraw-reveal
+ */
+static void
+age_withdraw_reveal_run (
+  void *cls,
+  const struct TALER_TESTING_Command *cmd,
+  struct TALER_TESTING_Interpreter *is)
+{
+  struct AgeWithdrawRevealState *awrs = cls;
+  const struct TALER_TESTING_Command *age_withdraw_cmd;
+  const struct AgeWithdrawState *aws;
+
+  (void) cmd;
+  awrs->is = is;
+
+  /*
+   * Get the command and state for the previous call to "age witdraw"
+   */
+  age_withdraw_cmd  =
+    TALER_TESTING_interpreter_get_command (is,
+                                           awrs->age_withdraw_reference);
+  if (NULL == age_withdraw_cmd)
+  {
+    GNUNET_break (0);
+    TALER_TESTING_interpreter_fail (is);
+  }
+  GNUNET_assert (age_withdraw_cmd->run == age_withdraw_run);
+  aws = age_withdraw_cmd->cls;
+  awrs->aws = aws;
+  awrs->num_coins = aws->num_coins;
+
+  awrs->handle =
+    TALER_EXCHANGE_age_withdraw_reveal (
+      TALER_TESTING_interpreter_get_context (is),
+      TALER_TESTING_get_exchange_url (is),
+      aws->num_coins,
+      aws->coin_inputs,
+      aws->noreveal_index,
+      &aws->h_commitment,
+      age_withdraw_reveal_cb,
+      awrs);
+}
+
+
+/**
+ * Free the state of a "age-withdraw-reveal" CMD, and possibly
+ * cancel a pending operation thereof
+ *
+ * @param cls Closure of type `struct AgeWithdrawRevealState`
+ * @param cmd The command being freed.
+ */
+static void
+age_withdraw_reveal_cleanup (
+  void *cls,
+  const struct TALER_TESTING_Command *cmd)
+{
+  struct AgeWithdrawRevealState *awrs = cls;
+
+  if (NULL != awrs->handle)
+  {
+    TALER_TESTING_command_incomplete (awrs->is,
+                                      cmd->label);
+    TALER_EXCHANGE_age_withdraw_reveal_cancel (awrs->handle);
+    awrs->handle = NULL;
+  }
+  GNUNET_free (awrs->denom_sigs);
+  awrs->denom_sigs = NULL;
+  GNUNET_free (awrs);
+}
+
+
+/**
+ * Offer internal data of a "age withdraw reveal" CMD state to other commands.
+ *
+ * @param cls Closure of they `struct AgeWithdrawRevealState`
+ * @param[out] ret result (could be anything)
+ * @param trait name of the trait
+ * @param idx index number of the object to offer.
+ * @return #GNUNET_OK on success
+ */
+static enum GNUNET_GenericReturnValue
+age_withdraw_reveal_traits (
+  void *cls,
+  const void **ret,
+  const char *trait,
+  unsigned int idx)
+{
+  struct AgeWithdrawRevealState *awrs = cls;
+  struct TALER_TESTING_Trait traits[] = {
+    TALER_TESTING_make_trait_denom_sig (idx,
+                                        &awrs->denom_sigs[idx]),
+    /* FIXME: shall we provide the traits from the previous
+     * call to "age withdraw" as well? */
+  };
+
+  if (idx >= awrs->num_coins)
+    return GNUNET_NO;
+
+  return TALER_TESTING_get_trait (traits,
+                                  ret,
+                                  trait,
+                                  idx);
+}
+
+
+struct TALER_TESTING_Command
+TALER_TESTING_cmd_age_withdraw_reveal (
+  const char *label,
+  const char *age_withdraw_reference,
+  unsigned int expected_response_code)
+{
+  struct AgeWithdrawRevealState *awrs =
+    GNUNET_new (struct AgeWithdrawRevealState);
+
+  awrs->age_withdraw_reference = age_withdraw_reference;
+  awrs->expected_response_code = expected_response_code;
+
+  struct TALER_TESTING_Command cmd = {
+    .cls = awrs,
+    .label = label,
+    .run = age_withdraw_reveal_run,
+    .cleanup = age_withdraw_reveal_cleanup,
+    .traits = age_withdraw_reveal_traits,
+  };
+
+  return cmd;
+}
+
+
 /* end of testing_api_cmd_age_withdraw.c */

src/testing/testing_api_cmd_batch_withdraw.c

@@ -23,6 +23,7 @@
  * @author Marcello Stanisci
  */
 #include "platform.h"
+#include "taler_exchange_service.h"
 #include "taler_json_lib.h"
 #include <microhttpd.h>
 #include <gnunet/gnunet_curl_lib.h>
@@ -217,7 +218,7 @@ reserve_batch_withdraw_cb (void *cls,
     /* nothing to check */
     break;
   case MHD_HTTP_CONFLICT:
-    /* nothing to check */
+    /* TODO[oec]: Check if age-requirement is the reason */
     break;
   case MHD_HTTP_GONE:
     /* theoretically could check that the key was actually */
@@ -250,6 +251,7 @@ batch_withdraw_run (void *cls,
                     struct TALER_TESTING_Interpreter *is)
 {
   struct BatchWithdrawState *ws = cls;
+  const struct TALER_EXCHANGE_Keys *keys =  TALER_TESTING_get_keys (is);
   const struct TALER_ReservePrivateKeyP *rp;
   const struct TALER_TESTING_Command *create_reserve;
   const struct TALER_EXCHANGE_DenomPublicKey *dpk;
@@ -292,7 +294,7 @@ batch_withdraw_run (void *cls,
     struct TALER_EXCHANGE_WithdrawCoinInput *wci = &wcis[i];
 
     TALER_planchet_master_setup_random (&cs->ps);
-    dpk = TALER_TESTING_find_pk (TALER_TESTING_get_keys (is),
+    dpk = TALER_TESTING_find_pk (keys,
                                  &cs->amount,
                                  ws->age > 0);
     if (NULL == dpk)
@@ -321,7 +323,7 @@ batch_withdraw_run (void *cls,
   ws->wsh = TALER_EXCHANGE_batch_withdraw (
     TALER_TESTING_interpreter_get_context (is),
     TALER_TESTING_get_exchange_url (is),
-    TALER_TESTING_get_keys (is),
+    keys,
     rp,
     ws->num_coins,
     wcis,

src/testing/testing_api_cmd_common.c

@@ -59,6 +59,20 @@ TALER_TESTING_history_entry_cmp (
          that should be good enough. */
       return 0;
     return 1;
+  case TALER_EXCHANGE_RTT_AGEWITHDRAWAL:
+    /* testing_api_cmd_age_withdraw doesn't set the out_authorization_sig,
+       so we cannot test for it here. but if the amount matches,
+       that should be good enough. */
+    if ( (0 ==
+          TALER_amount_cmp (&h1->amount,
+                            &h2->amount)) &&
+         (0 ==
+          TALER_amount_cmp (&h1->details.age_withdraw.fee,
+                            &h2->details.age_withdraw.fee)) &&
+         (h1->details.age_withdraw.max_age ==
+          h2->details.age_withdraw.max_age))
+      return 0;
+    return 1;
   case TALER_EXCHANGE_RTT_RECOUP:
     /* exchange_sig, exchange_pub and timestamp are NOT available
        from the original recoup response, hence here NOT check(able/ed) */

src/testing/testing_api_loop.c

@@ -31,6 +31,9 @@
 #include "taler_testing_lib.h"
 
 
+/**
+ * The interpreter and its state
+ */
 struct TALER_TESTING_Interpreter
 {