[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

1 files changed, 25 insertions, 3 deletions

diff --git a/src/include/taler_exchangedb_plugin.h b/src/include/taler_exchangedb_plugin.h
index ec647e9c..f0a6f8bd 100644
--- a/src/include/taler_exchangedb_plugin.h
+++ b/src/include/taler_exchangedb_plugin.h
@@ -70,6 +70,12 @@ struct TALER_EXCHANGEDB_DenominationKeyInformationP
    * Signed properties of the denomination key.
    */
   struct TALER_DenominationKeyValidityPS properties;
+
+  /**
+   * If denomination was setup for age restriction, non-zero age mask.
+   * Note that the mask is not part of the signature.
+   */
+  struct TALER_AgeMask age_mask;
 };
 
 
@@ -295,7 +301,7 @@ struct TALER_EXCHANGEDB_TableData
     struct
     {
       struct TALER_CoinSpendPublicKeyP coin_pub;
-      struct TALER_AgeHash age_hash;
+      struct TALER_AgeCommitmentHash age_hash;
       uint64_t denominations_serial;
       struct TALER_DenominationSignature denom_sig;
     } known_coins;
@@ -644,7 +650,7 @@ struct TALER_EXCHANGEDB_DenominationKeyMetaData
    * A value of 0 means that the denomination does not support the extension for
    * age-restriction.
    */
-  struct TALER_AgeMask age_restrictions;
+  struct TALER_AgeMask age_mask;
 };
 
 
@@ -1262,6 +1268,13 @@ struct TALER_EXCHANGEDB_Refresh
   struct TALER_CoinSpendSignatureP coin_sig;
 
   /**
+   * Hash of the age commitment used to sign the coin, if age restriction was
+   * applicable to the denomination.  May be all zeroes if no age restriction
+   * applies.
+   */
+  struct TALER_AgeCommitmentHash h_age_commitment;
+
+  /**
    * Refresh commitment this coin is melted into.
    */
   struct TALER_RefreshCommitmentP rc;
@@ -1307,6 +1320,13 @@ struct TALER_EXCHANGEDB_MeltListEntry
   struct TALER_DenominationHash h_denom_pub;
 
   /**
+   * Hash of the age commitment used to sign the coin, if age restriction was
+   * applicable to the denomination.  May be all zeroes if no age restriction
+   * applies.
+   */
+  struct TALER_AgeCommitmentHash h_age_commitment;
+
+  /**
    * How much value is being melted?  This amount includes the fees,
    * so the final amount contributed to the melt is this value minus
    * the fee for melting the coin.  We include the fee in what is
@@ -1606,6 +1626,7 @@ typedef enum GNUNET_GenericReturnValue
  * @param cls closure
  * @param rowid unique serial ID for the refresh session in our DB
  * @param denom_pub denomination public key of @a coin_pub
+ * @param h_age_commitment age commitment that went into the signing of the coin, may be NULL
  * @param coin_pub public key of the coin
  * @param coin_sig signature from the coin
  * @param amount_with_fee amount that was deposited including fee
@@ -1618,6 +1639,7 @@ typedef enum GNUNET_GenericReturnValue
   void *cls,
   uint64_t rowid,
   const struct TALER_DenominationPublicKey *denom_pub,
+  const struct TALER_AgeCommitmentHash *h_age_commitment,
   const struct TALER_CoinSpendPublicKeyP *coin_pub,
   const struct TALER_CoinSpendSignatureP *coin_sig,
   const struct TALER_Amount *amount_with_fee,
@@ -2758,7 +2780,7 @@ struct TALER_EXCHANGEDB_Plugin
                        const struct TALER_CoinPublicInfo *coin,
                        uint64_t *known_coin_id,
                        struct TALER_DenominationHash *denom_pub_hash,
-                       struct TALER_AgeHash *age_hash);
+                       struct TALER_AgeCommitmentHash *age_hash);
 
 
   /**