3 files changed, 162 insertions, 1 deletions
diff --git a/src/include/taler_crypto_lib.h b/src/include/taler_crypto_lib.h
index 1a3b40e4d..b6ec2ed8e 100644
--- a/src/include/taler_crypto_lib.h
+++ b/src/include/taler_crypto_lib.h
@@ -46,6 +46,7 @@
  * fixed and part of the protocol.
  */
 #define TALER_CNC_KAPPA 3
+#define TALER_CNC_KAPPA_MINUS_ONE_STR "2"
 
 
 /* ****************** Coin crypto primitives ************* */
@@ -436,6 +437,15 @@ struct TALER_AgeCommitmentPublicKeyP
 };
 
 
+/*
+ * @brief Hash to represent the commitment to n*kappa blinded keys during a age-withdrawal.
+ */
+struct TALER_AgeWithdrawCommitmentHashP
+{
+  struct GNUNET_HashCode hash;
+};
+
+
 /**
  * @brief Type of online public keys used by the wallet to establish a purse and the associated contract meta data.
  */
@@ -3701,6 +3711,42 @@ TALER_wallet_withdraw_verify (
 
 
 /**
+ * Sign age-withdraw request.
+ *
+ * @param h_commitment hash all n*kappa blinded coins in the commitment for the age-withdraw
+ * @param amount_with_fee amount to debit the reserve for
+ * @param max_age_group maximum age group that the withdrawn coins must be restricted to
+ * @param reserve_priv private key to sign with
+ * @param[out] reserve_sig resulting signature
+ */
+void
+TALER_wallet_age_withdraw_sign (
+  const struct TALER_AgeWithdrawCommitmentHashP *h_commitment,
+  const struct TALER_Amount *amount_with_fee,
+  uint32_t max_age_group,
+  const struct TALER_ReservePrivateKeyP *reserve_priv,
+  struct TALER_ReserveSignatureP *reserve_sig);
+
+/**
+ * Verify an age-withdraw request.
+ *
+ * @param h_commitment hash all n*kappa blinded coins in the commitment for the age-withdraw
+ * @param amount_with_fee amount to debit the reserve for
+ * @param max_age_group maximum age group that the withdrawn coins must be restricted to
+ * @param reserve_pub public key of the reserve
+ * @param reserve_sig resulting signature
+ * @return #GNUNET_OK if the signature is valid
+ */
+enum GNUNET_GenericReturnValue
+TALER_wallet_age_withdraw_verify (
+  const struct TALER_AgeWithdrawCommitmentHashP *h_commitment,
+  const struct TALER_Amount *amount_with_fee,
+  uint32_t max_age_group,
+  const struct TALER_ReservePublicKeyP *reserve_pub,
+  const struct TALER_ReserveSignatureP *reserve_sig);
+
+
+/**
  * Verify exchange melt confirmation.
  *
  * @param rc refresh session this is about
@@ -4789,6 +4835,25 @@ TALER_exchange_online_purse_status_verify (
   const struct TALER_ExchangeSignatureP *exchange_sig);
 
 
+/**
+ * Create age-withdraw confirmation signature.
+ *
+ * @param scb function to call to create the signature
+ * @param awch age-withdraw commitment that identifies the n*kappa blinded coins
+ * @param noreveal_index gamma cut-and-choose value chosen by the exchange
+ * @param[out] pub where to write the exchange public key
+ * @param[out] sig where to write the exchange signature
+ * @return #TALER_EC_NONE on success
+ */
+enum TALER_ErrorCode
+TALER_exchange_online_age_withdraw_confirmation_sign (
+  TALER_ExchangeSignCallback scb,
+  const struct TALER_AgeWithdrawCommitmentHashP *h_commitment,
+  uint32_t noreveal_index,
+  struct TALER_ExchangePublicKeyP *pub,
+  struct TALER_ExchangeSignatureP *sig);
+
+
 /* ********************* offline signing ************************** */
 
 
diff --git a/src/include/taler_exchangedb_plugin.h b/src/include/taler_exchangedb_plugin.h
index db3289ffc..2c606225d 100644
--- a/src/include/taler_exchangedb_plugin.h
+++ b/src/include/taler_exchangedb_plugin.h
@@ -1052,6 +1052,58 @@ struct TALER_EXCHANGEDB_CollectableBlindcoin
 
 
 /**
+ * @brief Information we keep for an age-withdraw commitment
+ * to reproduce the /age-withdraw operation if neede, and to have proof
+ * that a reserve was drained by this amount.
+ */
+struct TALER_EXCHANGEDB_AgeWithdrawCommitment
+{
+  /**
+   * Total amount (with fee) committed to withdraw
+   */
+  struct TALER_Amount amount_with_fee;
+
+  /**
+   * Maximum age group that the coins are restricted to.
+   */
+  uint32_t max_age_group;
+
+  /**
+   * The hash of the commitment of all n*kappa coins
+   */
+  struct TALER_AgeWithdrawCommitmentHashP h_commitment;
+
+  /**
+   * Index (smaller #TALER_CNC_KAPPA) which the exchange has chosen to not have
+   * revealed during cut and choose.  This value applies to all n coins in the
+   * commitment.
+   */
+  uint32_t noreveal_index;
+
+  /**
+   * Public key of the reserve that was drained.
+   */
+  struct TALER_ReservePublicKeyP reserve_pub;
+
+  /**
+   * Signature confirming the age withdrawal, matching @e reserve_pub, @e
+   * maximum_age_group and @e h_commitment and @e total_amount_with_fee.
+   */
+  struct TALER_ReserveSignatureP reserve_sig;
+
+  /**
+   * The exchange's signature of the response.
+   */
+  struct TALER_ExchangeSignatureP sig;
+
+  /**
+   * Timestamp of the request beeing made
+   */
+  struct GNUNET_TIME_Timestamp timestamp;
+};
+
+
+/**
  * Information the exchange records about a recoup request
  * in a reserve history.
  */
@@ -3608,6 +3660,46 @@ struct TALER_EXCHANGEDB_Plugin
     bool *nonce_reuse);
 
   /**
+   * Locate the response for a age-withdraw request under a hash that uniquely
+   * identifies the age-withdraw operation.  Used to ensure idempotency of the
+   * request.
+   *
+   * @param cls the @e cls of this struct with the plugin-specific state
+   * @param reserve_pub public key of the reserve for which the age-withdraw request is made
+   * @param ach hash that uniquely identifies the age-withdraw operation
+   * @param[out] awc corresponding details of the previous age-withdraw request if an entry was found
+   * @return statement execution status
+   */
+  enum GNUNET_DB_QueryStatus
+  (*get_age_withdraw_info)(
+    void *cls,
+    const struct TALER_ReservePublicKeyP *reserve_pub,
+    const struct TALER_AgeWithdrawCommitmentHashP *ach,
+    struct TALER_EXCHANGEDB_AgeWithdrawCommitment *awc);
+
+  /**
+   * Perform an age-withdraw operation, checking for sufficient balance
+   * and possibly persisting the withdrawal details.
+   *
+   * @param cls the `struct PostgresClosure` with the plugin-specific state
+   * @param commitment corresponding commitment for the age-withdraw
+   * @param now current time (rounded)
+   * @param[out] found set to true if the reserve was found
+   * @param[out] balance_ok set to true if the balance was sufficient
+   * @param[out] ruuid set to the reserve's UUID (reserves table row)
+   * @return query execution status
+   */
+  enum GNUNET_DB_QueryStatus
+  (*do_age_withdraw)(
+    void *cls,
+    const struct TALER_EXCHANGEDB_AgeWithdrawCommitment *commitment,
+    struct GNUNET_TIME_Timestamp now,
+    bool *found,
+    bool *balance_ok,
+    uint64_t *ruuid);
+
+
+  /**
    * Retrieve the details to a policy given by its hash_code
    *
    * @param cls the `struct PostgresClosure` with the plugin-specific state
diff --git a/src/include/taler_kyclogic_lib.h b/src/include/taler_kyclogic_lib.h
index 4b15b447a..44cc16e5b 100644
--- a/src/include/taler_kyclogic_lib.h
+++ b/src/include/taler_kyclogic_lib.h
@@ -73,8 +73,12 @@ enum TALER_KYCLOGIC_KycTriggerEvent
   /**
    * Reserve is being closed by force.
    */
-  TALER_KYCLOGIC_KYC_TRIGGER_RESERVE_CLOSE = 4
+  TALER_KYCLOGIC_KYC_TRIGGER_RESERVE_CLOSE = 4,
 
+  /**
+   * Customer withdraws coins via age-withdraw.
+   */
+  TALER_KYCLOGIC_KYC_TRIGGER_AGE_WITHDRAW = 5,
 };