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/*
This file is part of TALER
Copyright (C) 2014, 2015 Christian Grothoff (and other contributing authors)
TALER is free software; you can redistribute it and/or modify it under the
terms of the GNU 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 General Public License for more details.
You should have received a copy of the GNU General Public License along with
TALER; see the file COPYING. If not, If not, see <http://www.gnu.org/licenses/>
*/
/**
* @file taler_signatures.h
* @brief message formats and signature constants used to define
* the binary formats of signatures in Taler
* @author Florian Dold
* @author Benedikt Mueller
*
* This file should define the constants and C structs that one
* needs to know to implement Taler clients (wallets or merchants)
* that need to produce or verify Taler signatures.
*/
#ifndef TALER_SIGNATURES_H
#define TALER_SIGNATURES_H
#include "taler_util.h"
/**
* Cut-and-choose size for refreshing. Client looses the gamble (of
* unaccountable transfers) with probability 1/KAPPA. Refresh cost
* increases linearly with KAPPA, and 3 is sufficient up to a
* income/sales tax of 66% of total transaction value. As there is
* no good reason to change this security parameter, we declare it
* fixed and part of the protocol.
*/
#define KAPPA 3
/**
* Purpose for signing public keys signed
* by the mint master key.
*/
#define TALER_SIGNATURE_MASTER_SIGNKEY 1
/**
* Purpose for denomination keys signed
* by the mint master key.
*/
#define TALER_SIGNATURE_MASTER_DENOM 2
/**
* Purpose for the state of a reserve,
* signed by the mint's signing key.
*/
#define TALER_SIGNATURE_RESERVE_STATUS 3
/**
* Signature where the reserve key
* confirms a withdraw request.
*/
#define TALER_SIGNATURE_WITHDRAW 4
/**
* Signature using a coin key confirming the melting of
* a coin.
*/
#define TALER_SIGNATURE_REFRESH_MELT_COIN 5
/**
* Signature where the mint (current signing key)
* confirms the no-reveal index for cut-and-choose and
* the validity of the melted coins.
*/
#define TALER_SIGNATURE_REFRESH_MELT_RESPONSE 6
/**
* Signature where the Mint confirms a deposit request.
*/
#define TALER_SIGNATURE_MINT_DEPOSIT 7
/**
* Signature where the Mint confirms the full /keys response set.
*/
#define TALER_SIGNATURE_KEYS_SET 8
/***********************/
/* Merchant signatures */
/***********************/
/**
* Signature where the merchant confirms a contract
*/
#define TALER_SIGNATURE_MERCHANT_CONTRACT 101
/*********************/
/* Wallet signatures */
/*********************/
/**
* Signature made by the wallet of a user to confirm a deposit permission
*/
#define TALER_SIGNATURE_WALLET_DEPOSIT 201
/**
* Signature made by the wallet of a user to confirm a incremental deposit permission
*/
#define TALER_SIGNATURE_INCREMENTAL_WALLET_DEPOSIT 202
GNUNET_NETWORK_STRUCT_BEGIN
/**
* Format used for to generate the signature on a request to withdraw
* coins from a reserve.
*/
struct TALER_WithdrawRequest
{
/**
* Purpose must be #TALER_SIGNATURE_WITHDRAW.
*/
struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
/**
* Reserve public key (which reserve to withdraw from). This is
* the public key which must match the signature.
*/
struct TALER_ReservePublicKey reserve_pub;
/**
* Value of the coin being minted (matching the denomination key)
* plus the transaction fee. We include this in what is being
* signed so that we can verify a reserve's remaining total balance
* without needing to access the respective denomination key
* information each time.
*/
struct TALER_AmountNBO amount_with_fee;
/**
* Hash of the denomination public key for the coin that is withdrawn.
*/
struct GNUNET_HashCode h_denomination_pub;
/**
* Hash of the (blinded) message to be signed by the Mint.
*/
struct GNUNET_HashCode h_coin_envelope;
};
/**
* Format used to generate the signature on a request to deposit
* a coin into the account of a merchant.
*/
struct TALER_DepositRequest
{
/**
* Purpose must be #TALER_SIGNATURE_WALLET_DEPOSIT
*/
struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
/**
* Hash over the contract for which this deposit is made.
*/
struct GNUNET_HashCode h_contract;
/**
* Hash over the wiring information of the merchant.
*/
struct GNUNET_HashCode h_wire;
/**
* Merchant-generated transaction ID to detect duplicate
* transactions.
*/
uint64_t transaction_id GNUNET_PACKED;
/**
* Amount to be deposited, including fee.
*/
struct TALER_AmountNBO amount_with_fee;
/* FIXME: we should probably also include the value of
the depositing fee here as well! */
/**
* The coin's public key.
*/
struct TALER_CoinSpendPublicKey coin_pub;
};
/**
* Format used to generate the signature on a confirmation
* from the mint that a deposit request succeeded.
*/
struct TALER_DepositConfirmation
{
/**
* Purpose must be #TALER_SIGNATURE_MINT_DEPOSIT
*/
struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
/**
* Hash over the contract for which this deposit is made.
*/
struct GNUNET_HashCode h_contract;
/**
* Hash over the wiring information of the merchant.
*/
struct GNUNET_HashCode h_wire;
/**
* Merchant-generated transaction ID to detect duplicate
* transactions.
*/
uint64_t transaction_id GNUNET_PACKED;
/**
* Amount to be deposited, including fee.
*/
struct TALER_AmountNBO amount_with_fee;
/* FIXME: we should probably also include the value of
the depositing fee here as well! */
/**
* The coin's public key.
*/
struct TALER_CoinSpendPublicKey coin_pub;
/**
* The Merchant's public key.
*/
struct TALER_MerchantPublicKey merchant;
};
/**
* Message signed by a coin to indicate that the coin should
* be melted.
*/
struct RefreshMeltCoinSignature
{
/**
* Purpose is #TALER_SIGNATURE_REFRESH_MELT_COIN.
*/
struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
/**
* Which melting session should the coin become a part of.
*/
struct GNUNET_HashCode session_hash;
/**
* How much of the value of the coin should be melted? This amount
* includes the fees, so the final amount contributed to the melt is
* this value minus the fee for melting the coin. We include the
* fee in what is being signed so that we can verify a reserve's
* remaining total balance without needing to access the respective
* denomination key information each time.
*/
struct TALER_AmountNBO amount_with_fee;
/* FIXME: we should probably also include the value of
the melting fee here as well! */
/**
* The coin's public key.
*/
struct TALER_CoinSpendPublicKey coin_pub;
};
/**
* Format of the block signed by the Mint in response to a successful
* "/refresh/melt" request. Hereby the mint affirms that all of the
* coins were successfully melted. This also commits the mint to a
* particular index to not be revealed during the refresh.
*/
struct RefreshMeltResponseSignatureBody
{
/**
* Purpose is #TALER_SIGNATURE_REFRESH_MELT_RESPONSE.
*/
struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
/**
* Hash of the refresh session.
*/
struct GNUNET_HashCode session_hash;
/**
* Index that the client will not have to reveal.
*/
uint16_t noreveal_index GNUNET_PACKED;
};
/**
* Information about a signing key of the mint. Signing keys are used
* to sign mint messages other than coins, i.e. to confirm that a
* deposit was successful or that a refresh was accepted.
*/
struct TALER_MINT_SignKeyIssue
{
/**
* Signature over the signing key (by the master key of the mint).
*/
struct TALER_MasterSignature signature;
/**
* Purpose is #TALER_SIGNATURE_MASTER_SIGNKEY.
*/
struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
/**
* Master public key of the mint corresponding to @e signature.
* This is the long-term offline master key of the mint.
*/
struct TALER_MasterPublicKey master_pub;
/**
* When does this signing key begin to be valid?
*/
struct GNUNET_TIME_AbsoluteNBO start;
/**
* When does this signing key expire? Note: This is
* currently when the Mint will definitively stop using it.
* This does not mean that all signatures with tkey key are
* afterwards invalid.
*/
struct GNUNET_TIME_AbsoluteNBO expire;
/**
* The public online signing key that the mint will use
* between @e start and @e expire.
*/
struct TALER_MintPublicKey signkey_pub;
};
/**
* Signature made by the mint over the full set of keys, used
* to detect cheating mints that give out different sets to
* different users.
*/
struct TALER_MINT_KeySetSignature
{
/**
* Purpose is #TALER_SIGNATURE_KEYS_SET
*/
struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
/**
* Time of the key set issue.
*/
struct GNUNET_TIME_AbsoluteNBO list_issue_date;
/**
* Hash over the "inner" JSON with the key set.
*/
struct GNUNET_HashCode hc;
};
/**
* Information about a denomination key. Denomination keys
* are used to sign coins of a certain value into existence.
*/
struct TALER_MINT_DenomKeyIssue
{
/**
* Signature over this struct to affirm the validity
* of the key.
*/
struct TALER_MasterSignature signature;
/**
* Purpose is #TALER_SIGNATURE_MASTER_DENOM.
*/
struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
/**
* The long-term offline master key of the mint that was
* used to create @e signature.
*/
struct TALER_MasterPublicKey master;
/**
* Start time of the validity period for this key.
*/
struct GNUNET_TIME_AbsoluteNBO start;
/**
* The mint will sign fresh coins between @e start and
* this time.
*/
struct GNUNET_TIME_AbsoluteNBO expire_withdraw;
/**
* Coins signed with the denomination key must be spent or refreshed
* between @e start and this expiration time. After this time, the
* mint will refuse transactions involving this key as it will
* "drop" the table with double-spending information (shortly after)
* this time. Note that wallets should refresh coins significantly
* before this time to be on the safe side.
*/
struct GNUNET_TIME_AbsoluteNBO expire_spend;
/**
* The value of the coins signed with this denomination key.
*/
struct TALER_AmountNBO value;
/**
* The fee the mint charges when a coin of this type is withdrawn.
* (can be zero).
*/
struct TALER_AmountNBO fee_withdraw;
/**
* The fee the mint charges when a coin of this type is deposited.
* (can be zero).
*/
struct TALER_AmountNBO fee_deposit;
/**
* The fee the mint charges when a coin of this type is refreshed.
* (can be zero).
*/
struct TALER_AmountNBO fee_refresh;
/**
* Hash code of the denomination public key.
*/
struct GNUNET_HashCode denom_hash;
};
GNUNET_NETWORK_STRUCT_END
#endif
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