src/binary_formats.ml

@@ -422,7 +422,8 @@ module WithdrawConfirmationPS = struct
 end
 
 module SingleWithdrawRequestPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_WALLET_RESERVE_WITHDRAW *)
+  let purpose_code = Taler_signatures.wallet_reserve_withdraw
+
   type t = {
     amount_with_fee: AmountNBO.t;
     h_denomination_pub: DenominationHash.t;
@@ -431,7 +432,8 @@ module SingleWithdrawRequestPS = struct
 end
 
 module DepositRequestPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_WALLET_COIN_DEPOSIT *)
+  let purpose_code = Taler_signatures.wallet_coin_deposit
+
   type t = {
     h_contract_terms: PrivateContractHash.t;
     h_age_commitment: AgeCommitmentHash.t;
@@ -448,7 +450,8 @@ module DepositRequestPS = struct
 end
 
 module DepositConfirmationPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_CONFIRM_DEPOSIT *)
+  let purpose_code = Taler_signatures.exchange_confirm_deposit
+
   type t = {
     h_contract_terms: PrivateContractHash.t;
     h_wire: MerchantWireHash.t;
@@ -464,7 +467,8 @@ end
 module RefreshCommitmentP = MK_64 ()
 
 module RefreshMeltCoinAffirmationPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_WALLET_COIN_MELT *)
+  let purpose_code = Taler_signatures.wallet_coin_melt
+
   type t = {
     session_hash: RefreshCommitmentP.t;
     h_denom_pub: DenominationHash.t;
@@ -475,7 +479,8 @@ module RefreshMeltCoinAffirmationPS = struct
 end
 
 module RefreshMeltConfirmationPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_CONFIRM_MELT *)
+  let purpose_code = Taler_signatures.exchange_confirm_melt
+
   type t = {
     session_hash: RefreshCommitmentP.t;
     noreveal_index: int; (* uint16_t mapped to OCaml int *)
@@ -483,7 +488,8 @@ module RefreshMeltConfirmationPS = struct
 end
 
 module ExchangeSigningKeyValidityPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MASTER_SIGNING_KEY_VALIDITY *)
+  let purpose_code = Taler_signatures.master_signing_key_validity
+
   type t = {
     start: TimeAbsoluteNBO.t;
     expire: TimeAbsoluteNBO.t;
@@ -493,7 +499,8 @@ module ExchangeSigningKeyValidityPS = struct
 end
 
 module ExchangeKeySetPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_KEY_SET *)
+  let purpose_code = Taler_signatures.exchange_key_set
+
   type t = {
     list_issue_date: TimeAbsoluteNBO.t;
     hc: HashCode.t;
@@ -501,7 +508,8 @@ module ExchangeKeySetPS = struct
 end
 
 module DenominationKeyValidityPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MASTER_DENOMINATION_KEY_VALIDITY *)
+  let purpose_code = Taler_signatures.master_denomination_key_validity
+
   type t = {
     master: MasterPublicKeyP.t;
     start: TimeAbsoluteNBO.t;
@@ -517,7 +525,8 @@ module DenominationKeyValidityPS = struct
 end
 
 module MasterWireDetailsPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MASTER_WIRE_DETAILS *)
+  let purpose_code = Taler_signatures.master_wire_details
+
   type t = {
     h_wire_details: FullPaytoHash.t;
     h_conversion_url: HashCode.t;
@@ -527,7 +536,8 @@ module MasterWireDetailsPS = struct
 end
 
 module MasterWireFeePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MASTER_WIRE_FEES *)
+  let purpose_code = Taler_signatures.master_wire_fees
+
   type t = {
     h_wire_method: HashCode.t;
     start_date: TimeAbsoluteNBO.t;
@@ -538,7 +548,8 @@ module MasterWireFeePS = struct
 end
 
 module GlobalFeesPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MASTER_GLOBAL_FEES *)
+  let purpose_code = Taler_signatures.master_global_fees
+
   type t = {
     start_date: TimeAbsoluteNBO.t;
     end_date: TimeAbsoluteNBO.t;
@@ -554,7 +565,8 @@ module GlobalFeesPS = struct
 end
 
 module MasterDrainProfitPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MASTER_DRAIN_PROFITS *)
+  let purpose_code = Taler_signatures.master_drain_profits
+
   type t = {
     wtid: WireTransferIdentifierRawP.t;
     date: TimeAbsoluteNBO.t;
@@ -565,7 +577,8 @@ module MasterDrainProfitPS = struct
 end
 
 module DepositTrackPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MERCHANT_TRACK_TRANSACTION *)
+  let purpose_code = Taler_signatures.merchant_track_transaction
+
   type t = {
     h_contract_terms: PrivateContractHash.t;
     h_wire: MerchantWireHash.t;
@@ -584,7 +597,8 @@ module WireDepositDetailP = struct
 end
 
 module WireDepositDataPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_CONFIRM_WIRE_DEPOSIT *)
+  let purpose_code = Taler_signatures.exchange_confirm_wire_deposit
+
   type t = {
     total: AmountNBO.t;
     wire_fee: AmountNBO.t;
@@ -595,7 +609,8 @@ module WireDepositDataPS = struct
 end
 
 module ExchangeKeyValidityPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_AUDITOR_EXCHANGE_KEYS *)
+  let purpose_code = Taler_signatures.auditor_exchange_keys
+
   type t = {
     auditor_url_hash: HashCode.t;
     master: MasterPublicKeyP.t;
@@ -612,17 +627,20 @@ module ExchangeKeyValidityPS = struct
 end
 
 module PaymentResponsePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MERCHANT_PAYMENT_OK *)
+  let purpose_code = Taler_signatures.merchant_payment_ok
+
   type t = { h_contract_terms: PrivateContractHash.t }
 end
 
 module ContractPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MERCHANT_CONTRACT *)
+  let purpose_code = Taler_signatures.merchant_contract
+
   type t = { h_contract_terms: PrivateContractHash.t }
 end
 
 module ConfirmWirePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_CONFIRM_WIRE *)
+  let purpose_code = Taler_signatures.exchange_confirm_wire
+
   type t = {
     h_wire: MerchantWireHash.t;
     h_contract_terms: PrivateContractHash.t;
@@ -634,7 +652,8 @@ module ConfirmWirePS = struct
 end
 
 module RefundConfirmationPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_CONFIRM_REFUND *)
+  let purpose_code = Taler_signatures.exchange_confirm_refund
+
   type t = {
     h_contract_terms: PrivateContractHash.t;
     coin_pub: CoinSpendPublicKeyP.t;
@@ -645,7 +664,8 @@ module RefundConfirmationPS = struct
 end
 
 module DepositTrackPS2 = struct
-  (* purpose.purpose = TALER_SIGNATURE_MERCHANT_TRACK_TRANSACTION *)
+  let purpose_code = Taler_signatures.merchant_track_transaction
+
   type t = {
     h_contract_terms: PrivateContractHash.t;
     h_wire: MerchantWireHash.t;
@@ -655,7 +675,8 @@ module DepositTrackPS2 = struct
 end
 
 module RefundRequestPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MERCHANT_REFUND *)
+  let purpose_code = Taler_signatures.merchant_refund
+
   type t = {
     h_contract_terms: PrivateContractHash.t;
     coin_pub: CoinSpendPublicKeyP.t;
@@ -666,13 +687,17 @@ module RefundRequestPS = struct
 end
 
 module MerchantRefundConfirmationPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MERCHANT_REFUND_OK *)
+  let purpose_code = Taler_signatures.merchant_refund_ok
+
   (* Hash of the order ID (a string), hashed without the 0-termination. *)
   type t = { h_order_id: HashCode.t }
 end
 
 module RecoupRequestPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_WALLET_COIN_RECOUP or TALER_SIGNATURE_WALLET_COIN_RECOUP_REFRESH *)
+  (* two purpose_code possible here *)
+  let purpose_code_1 = Taler_signatures.wallet_coin_recoup
+  let purpose_code_2 = Taler_signatures.wallet_coin_recoup_refresh
+
   type t = {
     h_denom_pub: DenominationHash.t;
     coin_blind: DenominationBlindingKeyP.t;
@@ -680,7 +705,8 @@ module RecoupRequestPS = struct
 end
 
 module RecoupRefreshConfirmationPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_CONFIRM_RECOUP_REFRESH *)
+  let purpose_code = Taler_signatures.exchange_confirm_recoup_refresh
+
   type t = {
     timestamp: TimeAbsoluteNBO.t;
     recoup_amount: AmountNBO.t;
@@ -690,7 +716,8 @@ module RecoupRefreshConfirmationPS = struct
 end
 
 module RecoupConfirmationPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_CONFIRM_RECOUP *)
+  let purpose_code = Taler_signatures.exchange_confirm_recoup
+
   type t = {
     timestamp: TimeAbsoluteNBO.t;
     recoup_amount: AmountNBO.t;
@@ -700,7 +727,8 @@ module RecoupConfirmationPS = struct
 end
 
 module DenominationUnknownAffirmationPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_AFFIRM_DENOM_UNKNOWN *)
+  let purpose_code = Taler_signatures.exchange_affirm_denom_unknown
+
   type t = {
     timestamp: TimeAbsoluteNBO.t;
     h_denom_pub: DenominationHash.t;
@@ -708,7 +736,8 @@ module DenominationUnknownAffirmationPS = struct
 end
 
 module DenominationExpiredAffirmationPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_GENERIC_DENOMINATIN_EXPIRED *)
+  let purpose_code = Taler_signatures.exchange_generic_denominatin_expired
+
   type t = {
     timestamp: TimeAbsoluteNBO.t;
     operation: string; (* char[8] → string *)
@@ -717,7 +746,8 @@ module DenominationExpiredAffirmationPS = struct
 end
 
 module ReserveCloseConfirmationPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_RESERVE_CLOSED *)
+  let purpose_code = Taler_signatures.exchange_reserve_closed
+
   type t = {
     timestamp: TimeAbsoluteNBO.t;
     closing_amount: AmountNBO.t;
@@ -727,7 +757,8 @@ module ReserveCloseConfirmationPS = struct
 end
 
 module CoinLinkSignaturePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_WALLET_COIN_LINK *)
+  let purpose_code = Taler_signatures.wallet_coin_link
+
   type t = {
     h_denom_pub: DenominationHash.t;
     old_coin_pub: CoinSpendPublicKeyP.t;
@@ -737,17 +768,20 @@ module CoinLinkSignaturePS = struct
 end
 
 module RefreshNonceSignaturePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_WALLET_COIN_LINK *)
+  let purpose_code = Taler_signatures.wallet_coin_link
+
   type t = { nonce: PublicRefreshCoinNonceP.t }
 end
 
 module ReserveStatusRequestSignaturePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_RESERVE_STATUS_REQUEST *)
+  let purpose_code = Taler_signatures.reserve_status_request
+
   type t = { request_timestamp: TimeAbsoluteNBO.t }
 end
 
 module ReserveHistoryRequestSignaturePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_RESERVE_HISTORY_REQUEST *)
+  let purpose_code = Taler_signatures.reserve_history_request
+
   type t = {
     history_fee: AmountNBO.t;
     request_timestamp: TimeAbsoluteNBO.t;
@@ -755,12 +789,14 @@ module ReserveHistoryRequestSignaturePS = struct
 end
 
 module PurseStatusRequestSignaturePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_PURSE_STATUS_REQUEST *)
+  let purpose_code = Taler_signatures.purse_status_request
+
   type t = unit
 end
 
 module PurseStatusResponseSignaturePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_PURSE_STATUS_RESPONSE *)
+  let purpose_code = Taler_signatures.purse_status_response
+
   type t = {
     total_purse_amount: AmountNBO.t;
     total_deposit_amount: AmountNBO.t;
@@ -772,12 +808,14 @@ module PurseStatusResponseSignaturePS = struct
 end
 
 module ReserveCloseRequestSignaturePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_WALLET_RESERVE_CLOSE *)
+  let purpose_code = Taler_signatures.wallet_reserve_close
+
   type t = unit
 end
 
 module PurseRequestSignaturePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_WALLET_PURSE_CREATE *)
+  let purpose_code = Taler_signatures.wallet_purse_create
+
   type t = {
     purse_expiration: TimeAbsoluteNBO.t;
     merge_value_after_fees: AmountNBO.t;
@@ -787,7 +825,8 @@ module PurseRequestSignaturePS = struct
 end
 
 module PurseDepositSignaturePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_PURSE_DEPOSIT *)
+  let purpose_code = Taler_signatures.purse_deposit
+
   type t = {
     coin_contribution: AmountNBO.t;
     h_denom_pub: DenominationHash.t;
@@ -798,7 +837,8 @@ module PurseDepositSignaturePS = struct
 end
 
 module PurseDepositSignaturePS2 = struct
-  (* purpose.purpose = TALER_SIGNATURE_WALLET_RESERVE_OPEN_DEPOSIT *)
+  let purpose_code = Taler_signatures.wallet_reserve_open_deposit
+
   type t = {
     reserve_sig: ReserveSignatureP.t;
     coin_contribution: AmountNBO.t;
@@ -806,7 +846,8 @@ module PurseDepositSignaturePS2 = struct
 end
 
 module PurseDepositConfirmedSignaturePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_PURSE_DEPOSIT_CONFIRMED *)
+  let purpose_code = Taler_signatures.purse_deposit_confirmed
+
   type t = {
     total_purse_amount: AmountNBO.t;
     total_deposit_fees: AmountNBO.t;
@@ -817,7 +858,8 @@ module PurseDepositConfirmedSignaturePS = struct
 end
 
 module PurseMergeSignaturePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_WALLET_PURSE_MERGE *)
+  let purpose_code = Taler_signatures.wallet_purse_merge
+
   type t = {
     merge_timestamp: TimeAbsoluteNBO.t;
     h_wire: NormalizedPaytoHash.t;
@@ -825,7 +867,8 @@ module PurseMergeSignaturePS = struct
 end
 
 module AccountMergeSignaturePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_WALLET_ACCOUNT_MERGE *)
+  let purpose_code = Taler_signatures.wallet_account_merge
+
   type t = {
     reserve_pub: ReservePublicKeyP.t;
     purse_pub: PursePublicKey.t;
@@ -838,12 +881,14 @@ module AccountMergeSignaturePS = struct
 end
 
 module AccountSetupRequestSignaturePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_WALLET_ACCOUNT_SETUP *)
+  let purpose_code = Taler_signatures.wallet_account_setup
+
   type t = { threshold: AmountNBO.t }
 end
 
 module PurseMergeSuccessSignaturePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_PURSE_MERGE_SUCCESS *)
+  let purpose_code = Taler_signatures.purse_merge_success
+
   type t = {
     reserve_pub: ReservePublicKeyP.t;
     purse_pub: PursePublicKey.t;
@@ -856,7 +901,8 @@ module PurseMergeSuccessSignaturePS = struct
 end
 
 module WadDataSignaturePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_WAD_DATA *)
+  let purpose_code = Taler_signatures.wad_data
+
   type t = {
     wad_execution_time: TimeAbsoluteNBO.t;
     total_amount: AmountNBO.t;
@@ -866,7 +912,8 @@ module WadDataSignaturePS = struct
 end
 
 module WadPartnerSignaturePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MASTER_PARTNER_DETAILS *)
+  let purpose_code = Taler_signatures.master_partner_details
+
   type t = {
     h_partner_base_url: HashCode.t;
     master_public_key: MasterPublicKeyP.t;
@@ -878,7 +925,8 @@ module WadPartnerSignaturePS = struct
 end
 
 module P2PFeesPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_P2P_FEES *)
+  let purpose_code = Taler_signatures.p2p_fees
+
   type t = {
     start_date: TimeAbsoluteNBO.t;
     end_date: TimeAbsoluteNBO.t;
@@ -893,7 +941,8 @@ module P2PFeesPS = struct
 end
 
 module CoinPurseRefundConfirmationPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_CONFIRM_PURSE_REFUND *)
+  let purpose_code = Taler_signatures.exchange_confirm_purse_refund
+
   type t = {
     purse_pub: PursePublicKey.t;
     coin_pub: CoinSpendPublicKeyP.t;
@@ -903,7 +952,8 @@ module CoinPurseRefundConfirmationPS = struct
 end
 
 module DenominationKeyAnnouncementPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_SM_DENOMINATION_KEY *)
+  let purpose_code = Taler_signatures.sm_denomination_key
+
   type t = {
     h_denom_pub: DenominationHash.t;
     h_section_name: HashCode.t;
@@ -913,7 +963,8 @@ module DenominationKeyAnnouncementPS = struct
 end
 
 module SigningKeyAnnouncementPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_SM_SIGNING_KEY *)
+  let purpose_code = Taler_signatures.sm_signing_key
+
   type t = {
     exchange_pub: ExchangePublicKeyP.t;
     anchor_time: TimeAbsoluteNBO.t;
@@ -922,17 +973,20 @@ module SigningKeyAnnouncementPS = struct
 end
 
 module MasterDenominationKeyRevocationPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MASTER_DENOMINATION_KEY_REVOKED *)
+  let purpose_code = Taler_signatures.master_denomination_key_revoked
+
   type t = { h_denom_pub: DenominationHash.t }
 end
 
 module MasterSigningKeyRevocationPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MASTER_SIGNING_KEY_REVOKED *)
+  let purpose_code = Taler_signatures.master_signing_key_revoked
+
   type t = { exchange_pub: ExchangePublicKeyP.t }
 end
 
 module MasterAddAuditorPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MASTER_ADD_AUDITOR *)
+  let purpose_code = Taler_signatures.master_add_auditor
+
   type t = {
     start_date: TimeAbsoluteNBO.t;
     auditor_pub: AuditorPublicKeyP.t;
@@ -941,7 +995,8 @@ module MasterAddAuditorPS = struct
 end
 
 module MasterDelAuditorPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MASTER_DEL_AUDITOR *)
+  let purpose_code = Taler_signatures.master_del_auditor
+
   type t = {
     end_date: TimeAbsoluteNBO.t;
     auditor_pub: AuditorPublicKeyP.t;
@@ -949,7 +1004,8 @@ module MasterDelAuditorPS = struct
 end
 
 module MasterAddWirePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MASTER_ADD_WIRE *)
+  let purpose_code = Taler_signatures.master_add_wire
+
   type t = {
     start_date: TimeAbsoluteNBO.t;
     h_wire: FullPaytoHash.t;
@@ -960,7 +1016,8 @@ module MasterAddWirePS = struct
 end
 
 module MasterDelWirePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MASTER_DEL_WIRE *)
+  let purpose_code = Taler_signatures.master_del_wire
+
   type t = {
     end_date: TimeAbsoluteNBO.t;
     h_wire: FullPaytoHash.t;
@@ -968,7 +1025,8 @@ module MasterDelWirePS = struct
 end
 
 module MasterAmlOfficerStatusPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MASTER_AML_KEY *)
+  let purpose_code = Taler_signatures.master_aml_key
+
   type t = {
     change_date: TimeTimestampNBO.t;
     officer_pub: AmlOfficerPublicKeyP.t;
@@ -978,7 +1036,8 @@ module MasterAmlOfficerStatusPS = struct
 end
 
 module AmlDecisionPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_AML_DECISION *)
+  let purpose_code = Taler_signatures.aml_decision
+
   type t = {
     h_justification: HashCode.t;
     decision_time: TimeTimestampNBO.t;
@@ -990,7 +1049,8 @@ module AmlDecisionPS = struct
 end
 
 module PartnerConfigurationPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_MASTER_PARNTER_DETAILS *)
+  let purpose_code = Taler_signatures.master_parnter_details
+
   type t = {
     partner_pub: MasterPublicKeyP.t;
     start_date: TimeTimestampNBO.t;
@@ -1002,7 +1062,8 @@ module PartnerConfigurationPS = struct
 end
 
 module ReserveOpenPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_WALLET_RESERVE_OPEN *)
+  let purpose_code = Taler_signatures.wallet_reserve_open
+
   type t = {
     reserve_payment: AmountNBO.t;
     request_timestamp: TimeTimestampNBO.t;
@@ -1012,7 +1073,8 @@ module ReserveOpenPS = struct
 end
 
 module ReserveClosePS = struct
-  (* purpose.purpose = TALER_SIGNATURE_WALLET_RESERVE_CLOSE *)
+  let purpose_code = Taler_signatures.wallet_reserve_close
+
   type t = {
     request_timestamp: TimeTimestampNBO.t;
     target_account_h_payto: FullPaytoHash.t;
@@ -1020,7 +1082,8 @@ module ReserveClosePS = struct
 end
 
 module ReserveAttestRequestPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_WALLET_ATTEST_REQUEST *)
+  let purpose_code = Taler_signatures.wallet_attest_request
+
   type t = {
     request_timestamp: TimeTimestampNBO.t;
     h_details: HashCode.t;
@@ -1028,7 +1091,8 @@ module ReserveAttestRequestPS = struct
 end
 
 module ExchangeAttestPS = struct
-  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_RESERVE_ATTEST_DETAILS *)
+  let purpose_code = Taler_signatures.exchange_reserve_attest_details
+
   type t = {
     attest_timestamp: TimeTimestampNBO.t;
     expiration_time: TimeTimestampNBO.t;