[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, 12 insertions, 0 deletions

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);