1 files changed, 118 insertions, 5 deletions
diff --git a/src/lib/exchange_api_common.h b/src/lib/exchange_api_common.h
index 9c6d45029..9cbdf547f 100644
--- a/src/lib/exchange_api_common.h
+++ b/src/lib/exchange_api_common.h
@@ -23,6 +23,7 @@
 #define EXCHANGE_API_COMMON_H
 
 #include "taler_json_lib.h"
+#include "taler_exchange_service.h"
 
 
 /**
@@ -33,7 +34,7 @@
  * @param purse_pub the public key (must match
  *        the signature from the proof)
  * @param proof the proof to check
- * @return #GNUNET_OK if the @a proof is OK for @a purse_pub and conflicts with @a purse_sig
+ * @return #GNUNET_OK if the @a proof is OK for @a purse_pub and conflicts with @a cpurse_sig
  */
 enum GNUNET_GenericReturnValue
 TALER_EXCHANGE_check_purse_create_conflict_ (
@@ -51,7 +52,7 @@ TALER_EXCHANGE_check_purse_create_conflict_ (
  *        the signature from the proof)
  * @param exchange_url the base URL of this exchange
  * @param proof the proof to check
- * @return #GNUNET_OK if the @a proof is OK for @a purse_pub and conflicts with @a purse_sig
+ * @return #GNUNET_OK if the @a proof is OK for @a purse_pub and @a merge_pub and conflicts with @a cmerge_sig
  */
 enum GNUNET_GenericReturnValue
 TALER_EXCHANGE_check_purse_merge_conflict_ (
@@ -63,16 +64,38 @@ TALER_EXCHANGE_check_purse_merge_conflict_ (
 
 
 /**
- * Check proof of a contract conflict.
+ * Check @a proof that claims this coin was spend
+ * differently on the same purse already. Note that
+ * the caller must still check that @a coin_pub is
+ * in the list of coins that were used, and that
+ * @a coin_sig is different from the signature the
+ * caller used.
  *
- * DESIGN-FIXME: this 'proof' doesn't really proof a conflict!
+ * @param purse_pub the public key of the purse
+ * @param exchange_url base URL of our exchange
+ * @param proof the proof to check
+ * @param[out] coin_pub set to the conflicting coin
+ * @param[out] coin_sig set to the conflicting signature
+ * @return #GNUNET_OK if the @a proof is OK for @a purse_pub and showing that @a coin_pub was spent using @a coin_sig.
+ */
+enum GNUNET_GenericReturnValue
+TALER_EXCHANGE_check_purse_coin_conflict_ (
+  const struct TALER_PurseContractPublicKeyP *purse_pub,
+  const char *exchange_url,
+  const json_t *proof,
+  struct TALER_CoinSpendPublicKeyP *coin_pub,
+  struct TALER_CoinSpendSignatureP *coin_sig);
+
+
+/**
+ * Check proof of a contract conflict.
  *
  * @param ccontract_sig conflicting signature (must
  *        not match the signature from the proof)
  * @param purse_pub public key of the purse
  * @param exchange_url the base URL of this exchange
  * @param proof the proof to check
- * @return #GNUNET_OK if the @a proof is OK for @a purse_pub and conflicts with @a purse_sig
+ * @return #GNUNET_OK if the @a proof is OK for @a purse_pub and conflicts with @a ccontract_sig
  */
 enum GNUNET_GenericReturnValue
 TALER_EXCHANGE_check_purse_econtract_conflict_ (
@@ -81,4 +104,94 @@ TALER_EXCHANGE_check_purse_econtract_conflict_ (
   const json_t *proof);
 
 
+/**
+ * Check proof of a coin spend value conflict.
+ *
+ * @param keys exchange /keys structure
+ * @param proof the proof to check
+ * @param[out] coin_pub set to the public key of the
+ *        coin that is claimed to have an insufficient
+ *        balance
+ * @param[out] remaining set to the remaining balance
+ *        of the coin as provided by the proof
+ * @return #GNUNET_OK if the @a proof is OK for @a purse_pub demonstrating that @a coin_pub has only @a remaining balance.
+ */
+enum GNUNET_GenericReturnValue
+TALER_EXCHANGE_check_coin_amount_conflict_ (
+  const struct TALER_EXCHANGE_Keys *keys,
+  const json_t *proof,
+  struct TALER_CoinSpendPublicKeyP *coin_pub,
+  struct TALER_Amount *remaining);
+
+
+/**
+ * Verify that @a proof contains a coin history
+ * that demonstrates that @a coin_pub was previously
+ * used with a denomination key that is different
+ * from @a ch_denom_pub.  Note that the coin history
+ * MUST have been checked before using
+ * #TALER_EXCHANGE_check_coin_amount_conflict_().
+ *
+ * @param proof a proof to check
+ * @param ch_denom_pub hash of the conflicting denomination
+ * @return #GNUNET_OK if @a ch_denom_pub differs from the
+ *         denomination hash given by the history of the coin
+ */
+enum GNUNET_GenericReturnValue
+TALER_EXCHANGE_check_coin_denomination_conflict_ (
+  const json_t *proof,
+  const struct TALER_DenominationHashP *ch_denom_pub);
+
+
+/**
+ * Verify that @a coin_sig does NOT appear in
+ * the history of @a proof and thus whatever transaction
+ * is authorized by @a coin_sig is a conflict with
+ * @a proof.
+ *
+ * @param proof a proof to check
+ * @param coin_sig signature that must not be in @a proof
+ * @return #GNUNET_OK if @a coin_sig is not in @a proof
+ */
+enum GNUNET_GenericReturnValue
+TALER_EXCHANGE_check_coin_signature_conflict_ (
+  const json_t *proof,
+  const struct TALER_CoinSpendSignatureP *coin_sig);
+
+
+/**
+ * Check that the provided @a proof indeeds indicates
+ * a conflict for @a coin_pub.
+ *
+ * @param keys exchange keys
+ * @param proof provided conflict proof
+ * @param dk denomination of @a coin_pub that the client
+ *           used
+ * @param coin_pub public key of the coin
+ * @param coin_sig signature over operation that conflicted
+ * @param required balance required on the coin for the operation
+ * @return #GNUNET_OK if @a proof holds
+ */
+enum GNUNET_GenericReturnValue
+TALER_EXCHANGE_check_coin_conflict_ (
+  const struct TALER_EXCHANGE_Keys *keys,
+  const json_t *proof,
+  const struct TALER_EXCHANGE_DenomPublicKey *dk,
+  const struct TALER_CoinSpendPublicKeyP *coin_pub,
+  const struct TALER_CoinSpendSignatureP *coin_sig,
+  const struct TALER_Amount *required);
+
+
+/**
+ * Find the smallest denomination amount in @e keys.
+ *
+ * @param keys keys to search
+ * @param[out] min set to the smallest amount
+ * @return #GNUNET_SYSERR if there are no denominations in @a keys
+ */
+enum GNUNET_GenericReturnValue
+TALER_EXCHANGE_get_min_denomination_ (
+  const struct TALER_EXCHANGE_Keys *keys,
+  struct TALER_Amount *min);
+
 #endif