[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, 18 insertions, 0 deletions

diff --git a/src/include/taler_signatures.h b/src/include/taler_signatures.h
index 17ed4b57a..e3d9a8939 100644
--- a/src/include/taler_signatures.h
+++ b/src/include/taler_signatures.h
@@ -419,6 +419,11 @@ struct TALER_LinkDataPS
   struct TALER_TransferPublicKeyP transfer_pub;
 
   /**
+   * Hash of the age commitment, if applicable.  Can be all zero
+   */
+  struct TALER_AgeCommitmentHash h_age_commitment;
+
+  /**
    * Hash of the blinded new coin.
    */
   struct TALER_BlindedCoinHash coin_envelope_hash;
@@ -477,6 +482,12 @@ struct TALER_DepositRequestPS
   struct TALER_PrivateContractHash h_contract_terms GNUNET_PACKED;
 
   /**
+   * Hash over the age commitment that went into the coin. Maybe all zero, if
+   * age commitment isn't applicable to the denomination.
+   */
+  struct TALER_AgeCommitmentHash h_age_commitment GNUNET_PACKED;
+
+  /**
    * Hash over extension attributes shared with the exchange.
    */
   struct TALER_ExtensionContractHash h_extensions GNUNET_PACKED;
@@ -710,6 +721,13 @@ struct TALER_RefreshMeltCoinAffirmationPS
   struct TALER_DenominationHash h_denom_pub GNUNET_PACKED;
 
   /**
+   * If age commitment was provided during the withdrawal of the coin, this is
+   * the hash of the age commitment vector.  It must be all zeroes if no age
+   * commitment was provided.
+   */
+  struct TALER_AgeCommitmentHash h_age_commitment GNUNET_PACKED;
+
+  /**
    * How much of the value of the coin should be 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