583 lines
13 KiB
C
583 lines
13 KiB
C
/*
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This file is part of TALER
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Copyright (C) 2014, 2015 GNUnet e.V.
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TALER is free software; you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation; either version 3, or (at your option) any later version.
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TALER is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
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*/
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/**
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* @file include/taler_crypto_lib.h
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* @brief taler-specific crypto functions
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* @author Sree Harsha Totakura <sreeharsha@totakura.in>
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* @author Christian Grothoff <christian@grothoff.org>
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*/
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#ifndef TALER_CRYPTO_LIB_H
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#define TALER_CRYPTO_LIB_H
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#if HAVE_GNUNET_GNUNET_UTIL_LIB_H
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#include <gnunet/gnunet_util_lib.h>
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#include "taler_util.h"
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#elif HAVE_GNUNET_GNUNET_UTIL_TALER_WALLET_LIB_H
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#include <gnunet/gnunet_util_taler_wallet_lib.h>
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#include "taler_util_wallet.h"
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#endif
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#include <gcrypt.h>
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/* ****************** Coin crypto primitives ************* */
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GNUNET_NETWORK_STRUCT_BEGIN
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/**
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* @brief Type of public keys for Taler reserves.
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*/
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struct TALER_ReservePublicKeyP
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{
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/**
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* Taler uses EdDSA for reserves.
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*/
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struct GNUNET_CRYPTO_EddsaPublicKey eddsa_pub;
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};
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/**
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* @brief Type of private keys for Taler reserves.
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*/
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struct TALER_ReservePrivateKeyP
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{
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/**
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* Taler uses EdDSA for reserves.
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*/
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struct GNUNET_CRYPTO_EddsaPrivateKey eddsa_priv;
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};
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/**
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* @brief Type of signatures used with Taler reserves.
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*/
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struct TALER_ReserveSignatureP
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{
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/**
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* Taler uses EdDSA for reserves.
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*/
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struct GNUNET_CRYPTO_EddsaSignature eddsa_signature;
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};
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/**
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* @brief Type of public keys to for merchant authorizations.
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* Merchants can issue refunds using the corresponding
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* private key.
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*/
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struct TALER_MerchantPublicKeyP
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{
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/**
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* Taler uses EdDSA for merchants.
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*/
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struct GNUNET_CRYPTO_EddsaPublicKey eddsa_pub;
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};
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/**
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* @brief Type of private keys for merchant authorizations.
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* Merchants can issue refunds using the corresponding
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* private key.
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*/
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struct TALER_MerchantPrivateKeyP
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{
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/**
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* Taler uses EdDSA for merchants.
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*/
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struct GNUNET_CRYPTO_EddsaPrivateKey eddsa_priv;
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};
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/**
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* @brief Type of signatures made by merchants.
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*/
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struct TALER_MerchantSignatureP
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{
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/**
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* Taler uses EdDSA for merchants.
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*/
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struct GNUNET_CRYPTO_EddsaSignature eddsa_sig;
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};
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/**
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* @brief Type of transfer public keys used during refresh
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* operations.
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*/
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struct TALER_TransferPublicKeyP
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{
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/**
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* Taler uses ECDHE for transfer keys.
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*/
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struct GNUNET_CRYPTO_EcdhePublicKey ecdhe_pub;
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};
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/**
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* @brief Type of transfer public keys used during refresh
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* operations.
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*/
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struct TALER_TransferPrivateKeyP
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{
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/**
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* Taler uses ECDHE for melting session keys.
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*/
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struct GNUNET_CRYPTO_EcdhePrivateKey ecdhe_priv;
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};
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/**
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* @brief Type of online public keys used by the exchange to sign
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* messages.
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*/
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struct TALER_ExchangePublicKeyP
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{
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/**
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* Taler uses EdDSA for online exchange message signing.
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*/
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struct GNUNET_CRYPTO_EddsaPublicKey eddsa_pub;
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};
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/**
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* @brief Type of online public keys used by the exchange to
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* sign messages.
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*/
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struct TALER_ExchangePrivateKeyP
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{
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/**
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* Taler uses EdDSA for online signatures sessions.
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*/
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struct GNUNET_CRYPTO_EddsaPrivateKey eddsa_priv;
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};
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/**
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* @brief Type of signatures used by the exchange to sign messages online.
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*/
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struct TALER_ExchangeSignatureP
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{
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/**
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* Taler uses EdDSA for online signatures sessions.
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*/
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struct GNUNET_CRYPTO_EddsaSignature eddsa_signature;
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};
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/**
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* @brief Type of the offline master public key used by the exchange.
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*/
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struct TALER_MasterPublicKeyP
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{
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/**
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* Taler uses EdDSA for the long-term offline master key.
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*/
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struct GNUNET_CRYPTO_EddsaPublicKey eddsa_pub;
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};
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/**
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* @brief Type of the public key used by the auditor.
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*/
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struct TALER_AuditorPublicKeyP
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{
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/**
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* Taler uses EdDSA for the auditor's signing key.
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*/
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struct GNUNET_CRYPTO_EddsaPublicKey eddsa_pub;
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};
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/**
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* @brief Type of signatures used by the auditor.
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*/
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struct TALER_AuditorSignatureP
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{
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/**
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* Taler uses EdDSA signatures for auditors.
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*/
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struct GNUNET_CRYPTO_EddsaSignature eddsa_sig;
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};
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/**
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* @brief Type of the offline master public keys used by the exchange.
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*/
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struct TALER_MasterPrivateKeyP
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{
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/**
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* Taler uses EdDSA for the long-term offline master key.
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*/
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struct GNUNET_CRYPTO_EddsaPrivateKey eddsa_priv;
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};
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/**
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* @brief Type of signatures by the offline master public key used by the exchange.
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*/
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struct TALER_MasterSignatureP
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{
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/**
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* Taler uses EdDSA for the long-term offline master key.
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*/
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struct GNUNET_CRYPTO_EddsaSignature eddsa_signature;
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};
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/**
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* @brief Type of public keys for Taler coins. The same key material is used
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* for EdDSA and ECDHE operations.
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*/
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struct TALER_CoinSpendPublicKeyP
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{
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/**
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* Taler uses EdDSA for coins when signing deposit requests.
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*/
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struct GNUNET_CRYPTO_EddsaPublicKey eddsa_pub;
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};
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/**
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* @brief Type of private keys for Taler coins. The same key material is used
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* for EdDSA and ECDHE operations.
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*/
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struct TALER_CoinSpendPrivateKeyP
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{
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/**
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* Taler uses EdDSA for coins when signing deposit requests.
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*/
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struct GNUNET_CRYPTO_EddsaPrivateKey eddsa_priv;
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};
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/**
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* @brief Type of signatures made with Taler coins.
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*/
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struct TALER_CoinSpendSignatureP
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{
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/**
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* Taler uses EdDSA for coins.
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*/
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struct GNUNET_CRYPTO_EddsaSignature eddsa_signature;
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};
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/**
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* @brief Type of blinding keys for Taler.
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*/
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struct TALER_DenominationBlindingKeyP
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{
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/**
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* Taler uses RSA for blind signatures.
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*/
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struct GNUNET_CRYPTO_RsaBlindingKeySecret bks;
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};
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GNUNET_NETWORK_STRUCT_END
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/**
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* @brief Type of (unblinded) coin signatures for Taler.
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*/
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struct TALER_DenominationSignature
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{
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/**
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* Taler uses RSA for blinding.
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*/
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struct GNUNET_CRYPTO_RsaSignature *rsa_signature;
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};
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/**
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* @brief Type of public signing keys for verifying blindly signed coins.
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*/
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struct TALER_DenominationPublicKey
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{
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/**
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* Taler uses RSA for signing coins.
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*/
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struct GNUNET_CRYPTO_RsaPublicKey *rsa_public_key;
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};
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/**
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* @brief Type of private signing keys for blind signing of coins.
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*/
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struct TALER_DenominationPrivateKey
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{
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/**
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* Taler uses RSA for signing coins.
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*/
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struct GNUNET_CRYPTO_RsaPrivateKey *rsa_private_key;
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};
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/**
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* @brief Public information about a coin (including the public key
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* of the coin, the denomination key and the signature with
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* the denomination key).
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*/
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struct TALER_CoinPublicInfo
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{
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/**
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* The coin's public key.
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*/
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struct TALER_CoinSpendPublicKeyP coin_pub;
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/**
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* Public key representing the denomination of the coin
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* that is being deposited.
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*/
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struct TALER_DenominationPublicKey denom_pub;
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/**
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* (Unblinded) signature over @e coin_pub with @e denom_pub,
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* which demonstrates that the coin is valid.
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*/
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struct TALER_DenominationSignature denom_sig;
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};
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/**
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* Details for one of the /deposit operations that the
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* exchange combined into a single wire transfer.
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*/
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struct TALER_TrackTransferDetails
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{
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/**
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* Hash of the contract.
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*/
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struct GNUNET_HashCode h_contract;
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/**
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* Which coin was deposited?
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*/
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struct TALER_CoinSpendPublicKeyP coin_pub;
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/**
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* Value of the deposit (including fee).
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*/
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struct TALER_Amount coin_value;
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/**
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* Fee charged by the exchange for the deposit.
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*/
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struct TALER_Amount coin_fee;
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/**
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* Merchant's transaction identifier.
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*/
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uint64_t transaction_id;
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};
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/**
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* Check if a coin is valid; that is, whether the denomination key exists,
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* is not expired, and the signature is correct.
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*
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* @param coin_public_info the coin public info to check for validity
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* @return #GNUNET_YES if the coin is valid,
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* #GNUNET_NO if it is invalid
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* #GNUNET_SYSERROR if an internal error occured
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*/
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int
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TALER_test_coin_valid (const struct TALER_CoinPublicInfo *coin_public_info);
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/* ****************** Refresh crypto primitives ************* */
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GNUNET_NETWORK_STRUCT_BEGIN
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/**
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* @brief Secret used to decrypt the key to decrypt link secrets.
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*/
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struct TALER_TransferSecretP
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{
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/**
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* Secret used to derive private inputs for refreshed coins.
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* Must be (currently) a hash as this is what
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* #GNUNET_CRYPTO_ecc_ecdh() returns to us.
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*/
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struct GNUNET_HashCode key;
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};
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/**
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* Length of the raw value in the Taler wire transfer identifier
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* (in binary representation).
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*/
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#define TALER_WIRE_TRANSFER_IDENTIFIER_LEN 32
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/**
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* #TALER_WIRE_TRANSFER_IDENTIFIER_LEN as a string.
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*/
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#define TALER_WIRE_TRANSFER_IDENTIFIER_LEN_STR "32"
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/**
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* Raw value of a wire transfer subjects, without the checksum.
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*/
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struct TALER_WireTransferIdentifierRawP
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{
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/**
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* Raw value. Note that typical payment systems (SEPA, ACH) support
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* at least two lines of 27 ASCII characters to encode a transaction
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* subject or "details", for a total of 54 characters. (The payment
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* system protocols often support more lines, but the forms presented
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* to customers are usually limited to 54 characters.)
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*
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* With a Base32-encoding of 5 bit per character, this gives us 270
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* bits or (rounded down) 33 bytes. So we use the first 32 bytes to
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* encode the actual value (i.e. a 256-bit / 32-byte public key or
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* a hash code), and the last byte for a minimalistic checksum.
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*/
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uint8_t raw[TALER_WIRE_TRANSFER_IDENTIFIER_LEN];
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};
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/**
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* Binary information encoded in Crockford's Base32 in wire transfer
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* subjects of transfers from Taler to a merchant. The actual value
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* is chosen by the exchange and has no particular semantics, other than
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* being unique so that the exchange can lookup details about the wire
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* transfer when needed.
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*/
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struct TALER_WireTransferIdentifierP
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{
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/**
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* Raw value.
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*/
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struct TALER_WireTransferIdentifierRawP raw;
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/**
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* Checksum using CRC8 over the @e raw data.
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*/
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uint8_t crc8;
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};
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/**
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* @brief Representation of an encrypted refresh link.
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*/
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struct TALER_RefreshLinkEncryptedP
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{
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/**
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* Encrypted blinding key with @e blinding_key_enc_size bytes,
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* must be allocated at the end of this struct.
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*/
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char blinding_key_enc[sizeof (struct TALER_DenominationBlindingKeyP)];
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/**
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* Encrypted private key of the coin.
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*/
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char coin_priv_enc[sizeof (struct TALER_CoinSpendPrivateKeyP)];
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};
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GNUNET_NETWORK_STRUCT_END
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/**
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* Given the coin and the transfer private keys, compute the
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* transfer secret. (Technically, we only need one of the two
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* private keys, but the caller currently trivially only has
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* the two private keys, so we derive one of the public keys
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* internally to this function.)
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*
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* @param coin_priv coin key
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* @param trans_priv transfer private key
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* @param[out] ts computed transfer secret
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*/
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void
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TALER_link_derive_transfer_secret (const struct TALER_CoinSpendPrivateKeyP *coin_priv,
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const struct TALER_TransferPrivateKeyP *trans_priv,
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struct TALER_TransferSecretP *ts);
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/**
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* Decrypt the shared @a secret from the information in the
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* @a trans_priv and @a coin_pub.
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*
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* @param trans_priv transfer private key
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* @param coin_pub coin public key
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* @param[out] secret set to the shared secret
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*/
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void
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TALER_link_reveal_transfer_secret (const struct TALER_TransferPrivateKeyP *trans_priv,
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const struct TALER_CoinSpendPublicKeyP *coin_pub,
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struct TALER_TransferSecretP *transfer_secret);
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/**
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* Decrypt the shared @a secret from the information in the
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* @a trans_priv and @a coin_pub.
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*
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* @param trans_pub transfer private key
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* @param coin_priv coin public key
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* @param[out] secret set to the shared secret
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*/
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void
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TALER_link_recover_transfer_secret (const struct TALER_TransferPublicKeyP *trans_pub,
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const struct TALER_CoinSpendPrivateKeyP *coin_priv,
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struct TALER_TransferSecretP *transfer_secret);
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/**
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* Header for serializations of coin-specific information about the
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* fresh coins we generate during a melt.
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*/
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struct TALER_FreshCoinP
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{
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/**
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* Private key of the coin.
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*/
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struct TALER_CoinSpendPrivateKeyP coin_priv;
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/**
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* The blinding key.
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*/
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struct TALER_DenominationBlindingKeyP blinding_key;
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};
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/**
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* Setup information for a fresh coin, deriving the coin private key
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* and the blinding factor from the @a secret_seed with a KDF salted
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* by the @a coin_num_salt.
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*
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* @param secret_seed seed to use for KDF to derive coin keys
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* @param coin_num_salt number of the coin to include in KDF
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* @param[out] fc value to initialize
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*/
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void
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TALER_setup_fresh_coin (const struct TALER_TransferSecretP *secret_seed,
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unsigned int coin_num_salt,
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struct TALER_FreshCoinP *fc);
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#endif
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