mte/src/binary_formats.ml

(* https://docs.taler.net/core/api-common.html#binary-formats

   - numeric values are in network byte order (big endian) *)

(* structs that are ‘packed’ and do not contain pointers and are
   thus suitable for hashing or similar operations are distinguished
   by adding a “P” at the end of the name. (NEW) Note that this convention
   does not hold for the GNUnet-structs (yet).

   structs that are used with a purpose for signatures,
   additionally get an “S” at the end of the name.

   (from https://docs.taler.net/taler-developer-manual.html) *)

(* TODO
   - check that our struct are well packed
     - it looks like Bin only define packed structs
     - we don't need to worry about struct having "P" suffix
       remove them
   - test them
   - some purpose (`TALER_SIGNATURE_XXX`) are missing
     exchange and gana master branch are not in sync
     and we should use a specific git tag instead

   - clean up functor mess
     don't have not hash thing be HashCode like
   - have a make function for wrapped HashCode structs
     make it take the relevant type *)

module Taler_signatures = Include.Taler_signatures

(* -- Crypto keys -- *)

module RsaPublicKey = struct
  (* libgnuutil format:
     https://docs.gnunet.org/doxygen/d9/dbe/structGNUNET__CRYPTO__RsaPublicKeyHeaderP.html
     https://docs.gnunet.org/doxygen/d6/d70/group__libgnunetutil.html#ga9c99a81e8cd649c1c925d23211a0738f
     https://www.gnupg.org/documentation/manuals/gcrypt/MPI-formats.html

    format:
     - rsa header
     - modulus
     - public_exponent

    integer in big-endian format (MSB first).
    Leading zeroes are stripped unless they are required to keep a value positive.
  *)
  type header = {
    n_len: int;
    e_len: int;
  }

  type t = {
    header: header;
    n: Z.t;
    e: Z.t;
  }

  (* need to strip leading zeros or something? *)
  let z_to_bigendian_bits v =
    let s = Z.to_bits v in
    let len = String.length s in
    let s = String.init len (fun i -> s.[len - 1 - i]) in
    s

  let header_bin =
    let open Bin in
    record (fun n_len e_len -> { n_len; e_len })
    |+ field beint16 (fun t -> t.n_len)
    |+ field beint16 (fun t -> t.e_len)
    |> sealr

  let bin =
    let open Bin in
    record (fun header n e ->
        let n = Z.of_bits n in
        let e = Z.of_bits e in
        { header; n; e })
    |+ field header_bin (fun t -> t.header)
    (* TODO
         Z.to_bits is in little endian but we need it in big endian *)
    |+ field cstring (fun t -> z_to_bigendian_bits t.n)
    |+ field cstring (fun t -> z_to_bigendian_bits t.e)
    |> sealr
end

let int32_size = 4
let int64_size = 8

(* -- Time -- *)

(* microseconds since the UNIX Epoch. UINT64_MAX represents "never" *)
module MK_TIME () = struct
  type t = { v: int64 }

  (* not BE (?) *)
  let bin =
    let open Bin in
    record (fun v -> { v }) |+ field neint64 (fun t -> t.v) |> sealr
end

module MK_TIME_NBO () = struct
  type t = { v: int64 }

  let bin =
    let open Bin in
    record (fun v -> { v }) |+ field beint64 (fun t -> t.v) |> sealr
end

module TimeAbsolute = MK_TIME ()
module TimeAbsoluteNBO = MK_TIME_NBO ()
module TimeRelative = MK_TIME ()
module TimeRelativeNBO = MK_TIME_NBO ()
module Timestamp = MK_TIME ()
module TimestampNBO = MK_TIME_NBO ()

(* -- Cryptographic primitives -- *)

(* MK_BASIC_XX functor for structs like:
   struct Foo { uint8t bar[XX]; } *)
module MKMK_BASIC (S : sig
  val v : int
end) =
struct
  type t = { v: string }

  let bin =
    let open Bin in
    record (fun v -> { v }) |+ field (bytes S.v) (fun t -> t.v) |> sealr
end

module SIZE_32 = struct
  let v = 32
end

module SIZE_64 = struct
  let v = 64
end

module MK_BASIC_32 () = MKMK_BASIC (SIZE_32)
module MK_BASIC_64 () = MKMK_BASIC (SIZE_64)

(* MK_XX functor for structs like:
   struct FooWrap { struct Foo { uint8t bar[XX]; } } *)
module MKMK (S : sig
  val v : int
end) =
struct
  module H = MKMK_BASIC (S)

  type t = { v: H.t }

  let bin =
    let open Bin in
    record (fun v -> { v }) |+ field H.bin (fun t -> t.v) |> sealr
end

module MK_32 () = MKMK (SIZE_32)
module MK_64 () = MKMK (SIZE_64)
(* - *)

module ShortHashCode = MK_BASIC_32 ()
module HashCode = MK_BASIC_64 ()
module DenominationHash = MK_64 ()
module PrivateContractHash = MK_64 ()
module ExtensionsPolicyHash = MK_64 ()
module MerchantWireHash = MK_64 ()

(* Hash over a full payto://-URI, including receiver-name
   (and possibly BIC and other optional fields). *)
module FullPaytoHash = MK_32 ()

(* Hash over a normalized payto://-URI, including all optional
   fields and also with account-part canonicalized (so no BIC). *)
module NormalizedPaytoHash = MK_32 ()

(* TODO Taler doc: missing *)
module AgeCommitmentHash = MK_64 ()

(* TODO Taler doc: missing *)
module PublicRefreshCoinNonceP = MK_64 ()

(* TODO Taler doc: missing *)
module PursePublicKey = MK_32 ()

(* TODO Taler doc: missing *)
module AuditorPublicKeyP = MK_32 ()

(* TODO
   // Secret for blinding/unblinding.
   // An RSA blinding secret, which is basically
   // a 256-bit nonce, converted to Crockford `Base32`.
   type DenominationBlindingKeyP = string;
*)
module DenominationBlindingKeyP = MK_64 ()

(* Hash over:
     a) the hash of the denomination's public key,
     b) an enum value identifying the cipher, and
     c) cipher-dependant blinded information.
   See implementation of `TALER_CoinEvHash`
   in libtalerexchange for details. *)
module BlindedCoinHash = MK_64 ()

(* -- *)
module CoinPubHash = MK_64 ()
module OutputCommitmentHash = MK_64 ()
module ReservePublicKeyP = MK_32 ()
module ReservePrivateKeyP = MK_32 ()
module ReserveSignatureP = MK_64 ()
module MerchantPublicKeyP = MK_32 ()
module MerchantPrivateKeyP = MK_32 ()
(*module MerchantSignatureP = MK_64 () *)

module TransferPublicKeyP = MK_32 ()
module TransferPrivateKeyP = MK_32 ()

(*
enum TALER_AmlDecisionState {
  NORMAL, PENDING, FROZEN
};
*)

module AmlOfficerPublicKeyP = MK_32 ()
module AmlOfficerPrivateKeyP = MK_32 ()
module ExchangePublicKeyP = MK_32 ()
module ExchangePrivateKeyP = MK_32 ()
module ExchangeSignatureP = MK_64 ()
module MasterPublicKeyP = MK_32 ()
module MasterPrivateKeyP = MK_32 ()
module MasterSignatureP = MK_64 ()
module WireTransferIdentifierRawP = MK_BASIC_32 ()

module UUID = struct
  (* uint32t value[4]; *)
  type t = { value: string }

  let size = 4 * int32_size

  let bin =
    let open Bin in
    record (fun value -> { value })
    |+ field (bytes size) (fun t -> t.value)
    |> sealr
end

module WadId = struct
  (* uint32t value[6]; *)
  type t = { raw: string }

  let size = 6 * int32_size

  let bin =
    let open Bin in
    record (fun raw -> { raw }) |+ field (bytes size) (fun t -> t.raw) |> sealr
end

(* TODO not sure what to do of union, probably not needed *)
(*
union TALER_CoinSpendPublicKeyP {
  uint8t eddsaPub[32];
  uint8t ecdhePub[32];
};
union TALER_CoinSpendPrivateKeyP {
  uint8t eddsaPriv[32];
  uint8t ecdhePriv[32];
};
*)
module CoinSpendPublicKeyP = MK_32 ()
module CoinSpendPrivateKeyP = MK_32 ()
module CoinSpendSignatureP = MK_64 ()

(* TODO padding: sizeof used here (assume no padding for now) *)
(*
struct TALER_TransferSecretP {
  uint8t key[sizeof (struct HashCode)];
};
  uint8t key[sizeof (struct HashCode)];
};
struct TALER_EncryptedLinkSecretP {
  uint8t enc[sizeof (struct TALER_LinkSecretP)];
};
*)
module TransferSecretP = MK_64 ()
module LinkSecretP = MK_64 ()
module EncryptedLinkSecretP = MK_64 ()

(*
union TALER_TokenPublicKeyP {
  uint8t eddsaPub[32];
  uint8t ecdhePub[32];
};
*)
module TokenPublicKeyP = MK_32 ()

(* -- Signatures -- *)

(* EccSignaturePurpose *)
module Purpose = struct
  type t = {
    (* This field equals the number of bytes being signed,
       namely 'sizeof (struct Data)'. *)
    size: int32;
    (* This field is used to express the context in
       which the signature is made, ensuring that a
       signature cannot be lifted from one part of the protocol
       to another. *)
    purpose: int32;
  }

  let bin =
    let open Bin in
    record (fun size purpose -> { size; purpose })
    |+ field beint32 (fun t -> t.size)
    |+ field beint32 (fun t -> t.purpose)
    |> sealr

  let make ~size purpose = { size= Int32.of_int size; purpose }
  let dummy = make ~size:0 0_l

  (* helper function to make ['signature Bin.t] *)
  let make_bin =
    let get_size f =
      let open Bin in
      match Size.of_value (Size.size_of (f dummy)) with
      | Dynamic _ | Unknown ->
          Fmt.failwith "size_of failure: size is not Static"
      | Static n -> n
    in
    fun code f -> make ~size:(get_size f) code |> f

  let field purpose = Bin.field bin (fun _t -> purpose)
end

(* This is the running SHA512-hash over all
   `TALER_BlindedCoinHashP` values of an array of coins.
   Note that each `TALER_BlindedCoinHashP` itself
   captures the hash of the corresponding denomination's
   public key. *)
module HashPlanchetsP = MK_64 ()

module AgeMask = struct
  type t = { mask: int32 }

  let bin =
    let open Bin in
    record (fun mask -> { mask }) |+ field beint32 (fun t -> t.mask) |> sealr
end

(* TODO
   - why is the non-NBO version only used in TALER_WithdrawRequestPS? *)
(* Number of characters (plus 1 for 0-termination) for currency names.
   typically an ISO 4217 currency code when an alphanumeric 3-digit code is used.
   For regional currencies, the first character should be a "*" followed
   by a region-specific name (i.e. "*BRETAGNEFR").

   Currency string, left adjusted and padded with zeros.  All zeros
   for "invalid" values. *)
let currency_len = 12

(* TODO Taler doc: missing
   found in src/include/taler/taler_amount_lib.h *)
module Amount = struct
  type t = {
    value: int64;
    fraction: int32;
    currency: string;
  }

  (* TODO BE here? *)
  let bin =
    let open Bin in
    record (fun value fraction currency -> { value; fraction; currency })
    |+ field beint64 (fun t -> t.value)
    |+ field beint32 (fun t -> t.fraction)
    |+ field (bytes currency_len) (fun t -> t.currency)
    |> sealr
end

module AmountNBO = struct
  type t = {
    value: int64;
    fraction: int32;
    currency: string;
  }

  let bin =
    let open Bin in
    record (fun value fraction currency -> { value; fraction; currency })
    |+ field beint64 (fun t -> t.value)
    |+ field beint32 (fun t -> t.fraction)
    |+ field (bytes currency_len) (fun t -> t.currency)
    |> sealr
end

module BlindingMasterSeed = MK_BASIC_32 ()

module WithdrawRequestPS = struct
  (* Purpose is #TALER_SIGNATURE_WALLET_RESERVE_WITHDRAW *)
  type t = {
    amount: Amount.t;
    fee: Amount.t;
    h_planchets: HashPlanchetsP.t;
    (* TODO TALER doc
       `TALER_BlindingMasterSecretP` in doc, but probably TALER_BlindingMasterSeed *)
    blinding_seed: BlindingMasterSeed.t;
    max_age_group: int32;
    mask: AgeMask.t;
  }

  let bin =
    let open Bin in
    Purpose.make_bin Taler_signatures.wallet_reserve_withdraw @@ fun purpose ->
    record
      (fun _purpose amount fee h_planchets blinding_seed max_age_group mask ->
        { amount; fee; h_planchets; blinding_seed; max_age_group; mask })
    |+ Purpose.field purpose
    |+ field Amount.bin (fun t -> t.amount)
    |+ field Amount.bin (fun t -> t.fee)
    |+ field HashPlanchetsP.bin (fun t -> t.h_planchets)
    |+ field BlindingMasterSeed.bin (fun t -> t.blinding_seed)
    |+ field beint32 (fun t -> t.max_age_group)
    |+ field AgeMask.bin (fun t -> t.mask)
    |> sealr
end

module WithdrawConfirmationPS = struct
  (* Purpose is #TALER_SIGNATURE_EXCHANGE_CONFIRM_WITHDRAW.
     Signed by a `struct TALER_ExchangePrivateKeyP` using EdDSA. *)
  type t = {
    (* TODO TALER doc
       missing TALER_HashBlindedPlanchetsP*)
    h_planchets: HashPlanchetsP.t;
    noreveal_index: int32;
  }

  let bin =
    let open Bin in
    Purpose.make_bin Taler_signatures.exchange_confirm_withdraw
    @@ fun purpose ->
    record (fun _purpose h_planchets noreveal_index ->
        { h_planchets; noreveal_index })
    |+ Purpose.field purpose
    |+ field HashPlanchetsP.bin (fun t -> t.h_planchets)
    |+ field beint32 (fun t -> t.noreveal_index)
    |> sealr
end

module DenominationKeyAnnouncementPS = struct
  (* TODO taler_signatures purpose
     we use TALER_SIGNATURE_SM_RSA_DENOMINATION_KEY instead here *)
  (* purpose.purpose = TALER_SIGNATURE_SM_DENOMINATION_KEY *)
  type t = {
    h_denom_pub: DenominationHash.t;
    h_section_name: HashCode.t;
    anchor_time: TimeAbsoluteNBO.t;
    duration_withdraw: TimeRelativeNBO.t;
  }

  let bin =
    let open Bin in
    Purpose.make_bin Taler_signatures.sm_rsa_denomination_key @@ fun purpose ->
    record
      (fun _purpose h_denom_pub h_section_name anchor_time duration_withdraw ->
        { h_denom_pub; h_section_name; anchor_time; duration_withdraw })
    |+ Purpose.field purpose
    |+ field DenominationHash.bin (fun t -> t.h_denom_pub)
    |+ field HashCode.bin (fun t -> t.h_section_name)
    |+ field TimeAbsoluteNBO.bin (fun t -> t.anchor_time)
    |+ field TimeRelativeNBO.bin (fun t -> t.duration_withdraw)
    |> sealr
end

module SigningKeyAnnouncementPS = struct
  (* purpose.purpose = TALER_SIGNATURE_SM_SIGNING_KEY *)
  type t = {
    exchange_pub: ExchangePublicKeyP.t;
    anchor_time: TimeAbsoluteNBO.t;
    duration: TimeRelativeNBO.t;
  }

  let bin =
    let open Bin in
    Purpose.make_bin Taler_signatures.sm_signing_key @@ fun purpose ->
    record (fun _purpose exchange_pub anchor_time duration ->
        { exchange_pub; anchor_time; duration })
    |+ Purpose.field purpose
    |+ field ExchangePublicKeyP.bin (fun t -> t.exchange_pub)
    |+ field TimeAbsoluteNBO.bin (fun t -> t.anchor_time)
    |+ field TimeRelativeNBO.bin (fun t -> t.duration)
    |> sealr
end

(* --- BIN IMPL END --- *)

module SingleWithdrawRequestPS = struct
  (* purpose.purpose = TALER_SIGNATURE_WALLET_RESERVE_WITHDRAW *)
  type t = {
    amount_with_fee: AmountNBO.t;
    h_denomination_pub: DenominationHash.t;
    h_coin_envelope: BlindedCoinHash.t;
  }
end

module DepositRequestPS = struct
  (* purpose.purpose = TALER_SIGNATURE_WALLET_COIN_DEPOSIT *)
  type t = {
    h_contract_terms: PrivateContractHash.t;
    h_age_commitment: AgeCommitmentHash.t;
    h_policy: ExtensionsPolicyHash.t;
    h_wire: MerchantWireHash.t;
    h_denom_pub: DenominationHash.t;
    timestamp: TimeAbsoluteNBO.t;
    refund_deadline: TimeAbsoluteNBO.t;
    amount_with_fee: AmountNBO.t;
    deposit_fee: AmountNBO.t;
    merchant: MerchantPublicKeyP.t;
    wallet_data_hash: HashCode.t;
  }
end

module DepositConfirmationPS = struct
  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_CONFIRM_DEPOSIT *)
  type t = {
    h_contract_terms: PrivateContractHash.t;
    h_wire: MerchantWireHash.t;
    h_policy: ExtensionsPolicyHash.t;
    timestamp: TimeAbsoluteNBO.t;
    refund_deadline: TimeAbsoluteNBO.t;
    amount_without_fee: AmountNBO.t;
    coin_pub: CoinSpendPublicKeyP.t;
    merchant: MerchantPublicKeyP.t;
  }
end

module RefreshCommitmentP = MK_64 ()

module RefreshMeltCoinAffirmationPS = struct
  (* purpose.purpose = TALER_SIGNATURE_WALLET_COIN_MELT *)
  type t = {
    session_hash: RefreshCommitmentP.t;
    h_denom_pub: DenominationHash.t;
    h_age_commitment: AgeCommitmentHash.t;
    amount_with_fee: AmountNBO.t;
    melt_fee: AmountNBO.t;
  }
end

module RefreshMeltConfirmationPS = struct
  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_CONFIRM_MELT *)
  type t = {
    session_hash: RefreshCommitmentP.t;
    noreveal_index: int; (* uint16_t mapped to OCaml int *)
  }
end

module ExchangeSigningKeyValidityPS = struct
  (* purpose.purpose = TALER_SIGNATURE_MASTER_SIGNING_KEY_VALIDITY *)
  type t = {
    start: TimeAbsoluteNBO.t;
    expire: TimeAbsoluteNBO.t;
    end_: TimeAbsoluteNBO.t; (* "end" renamed to end_ *)
    signkey_pub: ExchangePublicKeyP.t;
  }
end

module ExchangeKeySetPS = struct
  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_KEY_SET *)
  type t = {
    list_issue_date: TimeAbsoluteNBO.t;
    hc: HashCode.t;
  }
end

module DenominationKeyValidityPS = struct
  (* purpose.purpose = TALER_SIGNATURE_MASTER_DENOMINATION_KEY_VALIDITY *)
  type t = {
    master: MasterPublicKeyP.t;
    start: TimeAbsoluteNBO.t;
    expire_withdraw: TimeAbsoluteNBO.t;
    expire_spend: TimeAbsoluteNBO.t;
    expire_legal: TimeAbsoluteNBO.t;
    value: AmountNBO.t;
    fee_withdraw: AmountNBO.t;
    fee_deposit: AmountNBO.t;
    fee_refresh: AmountNBO.t;
    denom_hash: DenominationHash.t;
  }
end

module MasterWireDetailsPS = struct
  (* purpose.purpose = TALER_SIGNATURE_MASTER_WIRE_DETAILS *)
  type t = {
    h_wire_details: FullPaytoHash.t;
    h_conversion_url: HashCode.t;
    h_credit_restrictions: HashCode.t;
    h_debit_restrictions: HashCode.t;
  }
end

module MasterWireFeePS = struct
  (* purpose.purpose = TALER_SIGNATURE_MASTER_WIRE_FEES *)
  type t = {
    h_wire_method: HashCode.t;
    start_date: TimeAbsoluteNBO.t;
    end_date: TimeAbsoluteNBO.t;
    wire_fee: AmountNBO.t;
    closing_fee: AmountNBO.t;
  }
end

module GlobalFeesPS = struct
  (* purpose.purpose = TALER_SIGNATURE_MASTER_GLOBAL_FEES *)
  type t = {
    start_date: TimeAbsoluteNBO.t;
    end_date: TimeAbsoluteNBO.t;
    purse_timeout: TimeRelativeNBO.t;
    kyc_timeout: TimeRelativeNBO.t;
    history_expiration: TimeRelativeNBO.t;
    history_fee: AmountNBO.t;
    kyc_fee: AmountNBO.t;
    account_fee: AmountNBO.t;
    purse_fee: AmountNBO.t;
    purse_account_limit: int; (* uint32_t → int *)
  }
end

module MasterDrainProfitPS = struct
  (* purpose.purpose = TALER_SIGNATURE_MASTER_DRAIN_PROFITS *)
  type t = {
    wtid: WireTransferIdentifierRawP.t;
    date: TimeAbsoluteNBO.t;
    amount: AmountNBO.t;
    h_section: HashCode.t;
    h_payto: FullPaytoHash.t;
  }
end

module DepositTrackPS = struct
  (* purpose.purpose = TALER_SIGNATURE_MERCHANT_TRACK_TRANSACTION *)
  type t = {
    h_contract_terms: PrivateContractHash.t;
    h_wire: MerchantWireHash.t;
    coin_pub: CoinSpendPublicKeyP.t;
  }
end

module WireDepositDetailP = struct
  type t = {
    h_contract_terms: PrivateContractHash.t;
    execution_time: TimeAbsoluteNBO.t;
    coin_pub: CoinSpendPublicKeyP.t;
    deposit_value: AmountNBO.t;
    deposit_fee: AmountNBO.t;
  }
end

module WireDepositDataPS = struct
  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_CONFIRM_WIRE_DEPOSIT *)
  type t = {
    total: AmountNBO.t;
    wire_fee: AmountNBO.t;
    merchant_pub: MerchantPublicKeyP.t;
    h_wire: MerchantWireHash.t;
    h_details: HashCode.t;
  }
end

module ExchangeKeyValidityPS = struct
  (* purpose.purpose = TALER_SIGNATURE_AUDITOR_EXCHANGE_KEYS *)
  type t = {
    auditor_url_hash: HashCode.t;
    master: MasterPublicKeyP.t;
    start: TimeAbsoluteNBO.t;
    expire_withdraw: TimeAbsoluteNBO.t;
    expire_spend: TimeAbsoluteNBO.t;
    expire_legal: TimeAbsoluteNBO.t;
    value: AmountNBO.t;
    fee_withdraw: AmountNBO.t;
    fee_deposit: AmountNBO.t;
    fee_refresh: AmountNBO.t;
    denom_hash: DenominationHash.t;
  }
end

module PaymentResponsePS = struct
  (* purpose.purpose = TALER_SIGNATURE_MERCHANT_PAYMENT_OK *)
  type t = { h_contract_terms: PrivateContractHash.t }
end

module ContractPS = struct
  (* purpose.purpose = TALER_SIGNATURE_MERCHANT_CONTRACT *)
  type t = { h_contract_terms: PrivateContractHash.t }
end

module ConfirmWirePS = struct
  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_CONFIRM_WIRE *)
  type t = {
    h_wire: MerchantWireHash.t;
    h_contract_terms: PrivateContractHash.t;
    wtid: WireTransferIdentifierRawP.t;
    coin_pub: CoinSpendPublicKeyP.t;
    execution_time: TimeAbsoluteNBO.t;
    coin_contribution: AmountNBO.t;
  }
end

module RefundConfirmationPS = struct
  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_CONFIRM_REFUND *)
  type t = {
    h_contract_terms: PrivateContractHash.t;
    coin_pub: CoinSpendPublicKeyP.t;
    merchant: MerchantPublicKeyP.t;
    rtransaction_id: int64;
    refund_amount: AmountNBO.t;
  }
end

module DepositTrackPS2 = struct
  (* purpose.purpose = TALER_SIGNATURE_MERCHANT_TRACK_TRANSACTION *)
  type t = {
    h_contract_terms: PrivateContractHash.t;
    h_wire: MerchantWireHash.t;
    merchant: MerchantPublicKeyP.t;
    coin_pub: CoinSpendPublicKeyP.t;
  }
end

module RefundRequestPS = struct
  (* purpose.purpose = TALER_SIGNATURE_MERCHANT_REFUND *)
  type t = {
    h_contract_terms: PrivateContractHash.t;
    coin_pub: CoinSpendPublicKeyP.t;
    rtransaction_id: int64;
    refund_amount: AmountNBO.t;
    refund_fee: AmountNBO.t;
  }
end

module MerchantRefundConfirmationPS = struct
  (* purpose.purpose = TALER_SIGNATURE_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 *)
  type t = {
    h_denom_pub: DenominationHash.t;
    coin_blind: DenominationBlindingKeyP.t;
  }
end

module RecoupRefreshConfirmationPS = struct
  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_CONFIRM_RECOUP_REFRESH *)
  type t = {
    timestamp: TimeAbsoluteNBO.t;
    recoup_amount: AmountNBO.t;
    coin_pub: CoinSpendPublicKeyP.t;
    old_coin_pub: CoinSpendPublicKeyP.t;
  }
end

module RecoupConfirmationPS = struct
  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_CONFIRM_RECOUP *)
  type t = {
    timestamp: TimeAbsoluteNBO.t;
    recoup_amount: AmountNBO.t;
    coin_pub: CoinSpendPublicKeyP.t;
    reserve_pub: ReservePublicKeyP.t;
  }
end

module DenominationUnknownAffirmationPS = struct
  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_AFFIRM_DENOM_UNKNOWN *)
  type t = {
    timestamp: TimeAbsoluteNBO.t;
    h_denom_pub: DenominationHash.t;
  }
end

module DenominationExpiredAffirmationPS = struct
  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_GENERIC_DENOMINATIN_EXPIRED *)
  type t = {
    timestamp: TimeAbsoluteNBO.t;
    operation: string; (* char[8] → string *)
    h_denom_pub: DenominationHash.t;
  }
end

module ReserveCloseConfirmationPS = struct
  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_RESERVE_CLOSED *)
  type t = {
    timestamp: TimeAbsoluteNBO.t;
    closing_amount: AmountNBO.t;
    reserve_pub: ReservePublicKeyP.t;
    h_wire: FullPaytoHash.t;
  }
end

module CoinLinkSignaturePS = struct
  (* purpose.purpose = TALER_SIGNATURE_WALLET_COIN_LINK *)
  type t = {
    h_denom_pub: DenominationHash.t;
    old_coin_pub: CoinSpendPublicKeyP.t;
    transfer_pub: TransferPublicKeyP.t;
    coin_envelope_hash: BlindedCoinHash.t;
  }
end

module RefreshNonceSignaturePS = struct
  (* purpose.purpose = TALER_SIGNATURE_WALLET_COIN_LINK *)
  type t = { nonce: PublicRefreshCoinNonceP.t }
end

module ReserveStatusRequestSignaturePS = struct
  (* purpose.purpose = TALER_SIGNATURE_RESERVE_STATUS_REQUEST *)
  type t = { request_timestamp: TimeAbsoluteNBO.t }
end

module ReserveHistoryRequestSignaturePS = struct
  (* purpose.purpose = TALER_SIGNATURE_RESERVE_HISTORY_REQUEST *)
  type t = {
    history_fee: AmountNBO.t;
    request_timestamp: TimeAbsoluteNBO.t;
  }
end

module PurseStatusRequestSignaturePS = struct
  (* purpose.purpose = TALER_SIGNATURE_PURSE_STATUS_REQUEST *)
  type t = unit
end

module PurseStatusResponseSignaturePS = struct
  (* purpose.purpose = TALER_SIGNATURE_PURSE_STATUS_RESPONSE *)
  type t = {
    total_purse_amount: AmountNBO.t;
    total_deposit_amount: AmountNBO.t;
    max_deposit_fees: AmountNBO.t;
    purse_expiration: TimeAbsoluteNBO.t;
    status_timestamp: TimeAbsoluteNBO.t;
    h_contract_terms: PrivateContractHash.t;
  }
end

module ReserveCloseRequestSignaturePS = struct
  (* purpose.purpose = TALER_SIGNATURE_WALLET_RESERVE_CLOSE *)
  type t = unit
end

module PurseRequestSignaturePS = struct
  (* purpose.purpose = TALER_SIGNATURE_WALLET_PURSE_CREATE *)
  type t = {
    purse_expiration: TimeAbsoluteNBO.t;
    merge_value_after_fees: AmountNBO.t;
    h_contract_terms: PrivateContractHash.t;
    min_age: int;
  }
end

module PurseDepositSignaturePS = struct
  (* purpose.purpose = TALER_SIGNATURE_PURSE_DEPOSIT *)
  type t = {
    coin_contribution: AmountNBO.t;
    h_denom_pub: DenominationHash.t;
    h_age_commitment: AgeCommitmentHash.t;
    purse_pub: PursePublicKey.t;
    h_exchange_base_url: HashCode.t;
  }
end

module PurseDepositSignaturePS2 = struct
  (* purpose.purpose = TALER_SIGNATURE_WALLET_RESERVE_OPEN_DEPOSIT *)
  type t = {
    reserve_sig: ReserveSignatureP.t;
    coin_contribution: AmountNBO.t;
  }
end

module PurseDepositConfirmedSignaturePS = struct
  (* purpose.purpose = TALER_SIGNATURE_PURSE_DEPOSIT_CONFIRMED *)
  type t = {
    total_purse_amount: AmountNBO.t;
    total_deposit_fees: AmountNBO.t;
    purse_pub: PursePublicKey.t;
    purse_expiration: TimeAbsoluteNBO.t;
    h_contract_terms: PrivateContractHash.t;
  }
end

module PurseMergeSignaturePS = struct
  (* purpose.purpose = TALER_SIGNATURE_WALLET_PURSE_MERGE *)
  type t = {
    merge_timestamp: TimeAbsoluteNBO.t;
    h_wire: NormalizedPaytoHash.t;
  }
end

module AccountMergeSignaturePS = struct
  (* purpose.purpose = TALER_SIGNATURE_WALLET_ACCOUNT_MERGE *)
  type t = {
    reserve_pub: ReservePublicKeyP.t;
    purse_pub: PursePublicKey.t;
    merge_amount_after_fees: AmountNBO.t;
    merge_timestamp: TimeAbsoluteNBO.t;
    purse_expiration: TimeAbsoluteNBO.t;
    h_contract_terms: PrivateContractHash.t;
    min_age: int;
  }
end

module AccountSetupRequestSignaturePS = struct
  (* purpose.purpose = TALER_SIGNATURE_WALLET_ACCOUNT_SETUP *)
  type t = { threshold: AmountNBO.t }
end

module PurseMergeSuccessSignaturePS = struct
  (* purpose.purpose = TALER_SIGNATURE_PURSE_MERGE_SUCCESS *)
  type t = {
    reserve_pub: ReservePublicKeyP.t;
    purse_pub: PursePublicKey.t;
    merge_amount_after_fees: AmountNBO.t;
    contract_time: TimeAbsoluteNBO.t;
    h_contract_terms: PrivateContractHash.t;
    h_wire: NormalizedPaytoHash.t;
    min_age: int;
  }
end

module WadDataSignaturePS = struct
  (* purpose.purpose = TALER_SIGNATURE_WAD_DATA *)
  type t = {
    wad_execution_time: TimeAbsoluteNBO.t;
    total_amount: AmountNBO.t;
    h_items: HashCode.t;
    wad_id: WadId.t;
  }
end

module WadPartnerSignaturePS = struct
  (* purpose.purpose = TALER_SIGNATURE_MASTER_PARTNER_DETAILS *)
  type t = {
    h_partner_base_url: HashCode.t;
    master_public_key: MasterPublicKeyP.t;
    start_date: TimeAbsoluteNBO.t;
    end_date: TimeAbsoluteNBO.t;
    wad_fee: AmountNBO.t;
    wad_frequency: TimeRelativeNBO.t;
  }
end

module P2PFeesPS = struct
  (* purpose.purpose = TALER_SIGNATURE_P2P_FEES *)
  type t = {
    start_date: TimeAbsoluteNBO.t;
    end_date: TimeAbsoluteNBO.t;
    kyc_fee: AmountNBO.t;
    purse_fee: AmountNBO.t;
    account_history_fee: AmountNBO.t;
    account_annual_fee: AmountNBO.t;
    account_kyc_timeout: TimeRelativeNBO.t;
    purse_timeout: TimeRelativeNBO.t;
    purse_account_limit: int;
  }
end

module CoinPurseRefundConfirmationPS = struct
  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_CONFIRM_PURSE_REFUND *)
  type t = {
    purse_pub: PursePublicKey.t;
    coin_pub: CoinSpendPublicKeyP.t;
    refunded_amount: AmountNBO.t;
    refund_fee: AmountNBO.t;
  }
end

module MasterDenominationKeyRevocationPS = struct
  (* purpose.purpose = TALER_SIGNATURE_MASTER_DENOMINATION_KEY_REVOKED *)
  type t = { h_denom_pub: DenominationHash.t }
end

module MasterSigningKeyRevocationPS = struct
  (* purpose.purpose = TALER_SIGNATURE_MASTER_SIGNING_KEY_REVOKED *)
  type t = { exchange_pub: ExchangePublicKeyP.t }
end

module MasterAddAuditorPS = struct
  (* purpose.purpose = TALER_SIGNATURE_MASTER_ADD_AUDITOR *)
  type t = {
    start_date: TimeAbsoluteNBO.t;
    auditor_pub: AuditorPublicKeyP.t;
    h_auditor_url: HashCode.t;
  }
end

module MasterDelAuditorPS = struct
  (* purpose.purpose = TALER_SIGNATURE_MASTER_DEL_AUDITOR *)
  type t = {
    end_date: TimeAbsoluteNBO.t;
    auditor_pub: AuditorPublicKeyP.t;
  }
end

module MasterAddWirePS = struct
  (* purpose.purpose = TALER_SIGNATURE_MASTER_ADD_WIRE *)
  type t = {
    start_date: TimeAbsoluteNBO.t;
    h_wire: FullPaytoHash.t;
    h_conversion_url: HashCode.t;
    h_credit_restrictions: HashCode.t;
    h_debit_restrictions: HashCode.t;
  }
end

module MasterDelWirePS = struct
  (* purpose.purpose = TALER_SIGNATURE_MASTER_DEL_WIRE *)
  type t = {
    end_date: TimeAbsoluteNBO.t;
    h_wire: FullPaytoHash.t;
  }
end

module MasterAmlOfficerStatusPS = struct
  (* purpose.purpose = TALER_SIGNATURE_MASTER_AML_KEY *)
  type t = {
    change_date: TimestampNBO.t;
    officer_pub: AmlOfficerPublicKeyP.t;
    h_officer_name: HashCode.t;
    is_active: int;
  }
end

module AmlDecisionPS = struct
  (* purpose.purpose = TALER_SIGNATURE_AML_DECISION *)
  type t = {
    h_justification: HashCode.t;
    decision_time: TimestampNBO.t;
    new_threshold: AmountNBO.t;
    h_payto: NormalizedPaytoHash.t;
    h_kyc_requirements: HashCode.t;
    new_state: int;
  }
end

module PartnerConfigurationPS = struct
  (* purpose.purpose = TALER_SIGNATURE_MASTER_PARNTER_DETAILS *)
  type t = {
    partner_pub: MasterPublicKeyP.t;
    start_date: TimestampNBO.t;
    end_date: TimestampNBO.t;
    wad_frequency: TimeRelativeNBO.t;
    wad_fee: AmountNBO.t;
    h_url: HashCode.t;
  }
end

module ReserveOpenPS = struct
  (* purpose.purpose = TALER_SIGNATURE_WALLET_RESERVE_OPEN *)
  type t = {
    reserve_payment: AmountNBO.t;
    request_timestamp: TimestampNBO.t;
    reserve_expiration: TimestampNBO.t;
    purse_limit: int;
  }
end

module ReserveClosePS = struct
  (* purpose.purpose = TALER_SIGNATURE_WALLET_RESERVE_CLOSE *)
  type t = {
    request_timestamp: TimestampNBO.t;
    target_account_h_payto: FullPaytoHash.t;
  }
end

module ReserveAttestRequestPS = struct
  (* purpose.purpose = TALER_SIGNATURE_WALLET_ATTEST_REQUEST *)
  type t = {
    request_timestamp: TimestampNBO.t;
    h_details: HashCode.t;
  }
end

module ExchangeAttestPS = struct
  (* purpose.purpose = TALER_SIGNATURE_EXCHANGE_RESERVE_ATTEST_DETAILS *)
  type t = {
    attest_timestamp: TimestampNBO.t;
    expiration_time: TimestampNBO.t;
    reserve_pub: ReservePublicKeyP.t;
    h_attributes: HashCode.t;
  }
end