WiP: age-withdraw implementation, part 2/n

Commit phase of the age-withdraw protocol implemented, according to
https://docs.taler.net/core/api-exchange.html#withdraw-with-age-restriction

- added new files, forgot in previous commit

1 files changed, 56 insertions, 0 deletions

diff --git a/src/exchange/taler-exchange-httpd_age-withdraw_reveal.h b/src/exchange/taler-exchange-httpd_age-withdraw_reveal.h
new file mode 100644
index 00000000..73ebc6fb
--- /dev/null
+++ b/src/exchange/taler-exchange-httpd_age-withdraw_reveal.h
@@ -0,0 +1,56 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2023 Taler Systems SA
+
+  TALER is free software; you can redistribute it and/or modify it under the
+  terms of the GNU Affero General Public License as published by the Free Software
+  Foundation; either version 3, or (at your option) any later version.
+
+  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+  A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.
+
+  You should have received a copy of the GNU Affero General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file taler-exchange-httpd_age-withdraw_reveal.h
+ * @brief Handle /age-withdraw/$ACH/reveal requests
+ * @author Özgür Kesim
+ */
+#ifndef TALER_EXCHANGE_HTTPD_AGE_WITHDRAW_H
+#define TALER_EXCHANGE_HTTPD_AGE_WITHDRAW_H
+
+#include <microhttpd.h>
+#include "taler-exchange-httpd.h"
+
+
+/**
+ * Handle a "/age-withdraw/$ACH/reveal" request.
+ *
+ * The client got a noreveal_index in response to a previous request
+ * /reserve/$RESERVE_PUB/age-withdraw.  It now has to reveal all n*(kappa-1)
+ * coin's private keys (except for the noreveal_index), from which all other
+ * coin-relevant data (blinding, age restriction, nonce) is derived from.
+ *
+ * The exchange computes those values, ensures that the maximum age is
+ * correctly applied, calculates the hash of the blinded envelopes, and -
+ * together with the non-disclosed blinded envelopes - compares the hash of
+ * those against the original commitment $ACH.
+ *
+ * If all those checks and the used denominations turn out to be correct, the
+ * exchange signs all blinded envelopes with their appropriate denomination
+ * keys.
+ *
+ * @param rc request context
+ * @param root uploaded JSON data
+ * @param ach commitment to the age restricted coints from the age-withdraw request
+ * @return MHD result code
+ */
+MHD_RESULT
+TEH_handler_age_withdraw_reveal (
+  struct TEH_RequestContext *rc,
+  const struct TALER_AgeWithdrawCommitmentHashP *ach,
+  const json_t *root);
+
+#endif