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/*
This file is part of TALER
Copyright (C) 2018 Taler Systems SA
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, see <http://www.gnu.org/licenses/>
*/
/**
* @file util/crypto_wire.c
* @brief functions for making and verifying /wire account signatures
* @author Christian Grothoff <christian@grothoff.org>
*/
#include "platform.h"
#include "taler_crypto_lib.h"
#include "taler_signatures.h"
/**
* Compute the hash of the given wire details. The resulting
* hash is what is signed by the master key.
*
* @param payto_uri bank account
* @param[out] hc set to the hash
*/
void
TALER_exchange_wire_signature_hash (const char *payto_uri,
struct GNUNET_HashCode *hc)
{
GNUNET_assert (GNUNET_YES ==
GNUNET_CRYPTO_kdf (hc,
sizeof (*hc),
payto_uri,
strlen (payto_uri) + 1,
"exchange-wire-signature",
strlen ("exchange-wire-signature"),
NULL, 0));
}
/**
* Check the signature in @a master_sig.
*
* @param payto_uri URL that is signed
* @param master_pub master public key of the exchange
* @param master_sig signature of the exchange
* @return #GNUNET_OK if signature is valid
*/
enum GNUNET_GenericReturnValue
TALER_exchange_wire_signature_check (
const char *payto_uri,
const struct TALER_MasterPublicKeyP *master_pub,
const struct TALER_MasterSignatureP *master_sig)
{
struct TALER_MasterWireDetailsPS wd = {
.purpose.purpose = htonl (TALER_SIGNATURE_MASTER_WIRE_DETAILS),
.purpose.size = htonl (sizeof (wd))
};
TALER_exchange_wire_signature_hash (payto_uri,
&wd.h_wire_details);
return GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_MASTER_WIRE_DETAILS,
&wd,
&master_sig->eddsa_signature,
&master_pub->eddsa_pub);
}
/**
* Create a signed wire statement for the given account.
*
* @param payto_uri account specification
* @param master_priv private key to sign with
* @param[out] master_sig where to write the signature
*/
void
TALER_exchange_wire_signature_make (
const char *payto_uri,
const struct TALER_MasterPrivateKeyP *master_priv,
struct TALER_MasterSignatureP *master_sig)
{
struct TALER_MasterWireDetailsPS wd = {
.purpose.purpose = htonl (TALER_SIGNATURE_MASTER_WIRE_DETAILS),
.purpose.size = htonl (sizeof (wd))
};
TALER_exchange_wire_signature_hash (payto_uri,
&wd.h_wire_details);
GNUNET_CRYPTO_eddsa_sign (&master_priv->eddsa_priv,
&wd,
&master_sig->eddsa_signature);
}
/**
* Compute the hash of the given wire details. The resulting
* @a hc is what will be put into the contract between customer
* and merchant for signing by both parties.
*
* @param payto_uri bank account
* @param salt salt used to eliminate brute-force inversion
* @param[out] hc set to the hash
*/
void
TALER_merchant_wire_signature_hash (const char *payto_uri,
const struct TALER_WireSalt *salt,
struct GNUNET_HashCode *hc)
{
#if FIXED_7032
/* new logic to use once #7032 is being addressed */
GNUNET_assert (GNUNET_YES ==
GNUNET_CRYPTO_kdf (hc,
sizeof (*hc),
salt,
sizeof (*salt),
payto_uri,
strlen (payto_uri) + 1,
"merchant-wire-signature",
strlen ("merchant-wire-signature"),
NULL, 0));
#else
/* compatibility logic to avoid protocol breakage... */
char *sstr;
sstr = GNUNET_STRINGS_data_to_string_alloc (salt,
sizeof (*salt));
GNUNET_assert (GNUNET_YES ==
GNUNET_CRYPTO_kdf (hc,
sizeof (*hc),
sstr,
strlen (sstr) + 1,
payto_uri,
strlen (payto_uri) + 1,
"merchant-wire-signature",
strlen ("merchant-wire-signature"),
NULL, 0));
GNUNET_free (sstr);
#endif
}
/**
* Check the signature in @a merch_sig.
* (Not yet used anywhere.)
*
* Expected to be used if/when we get @a merch_pub signed via
* X.509 *and* have a way for the WebEx wallet to check that the
* @a merch_pub provided matches that of the X.509 certificate
* from the Web site. Until then, @a merch_pub cannto be
* validated (no PKI), and hence there is no point in checking
* these signatures. (See #5129 and #3946).
*
* @param payto_uri URL that is signed
* @param salt the salt used to salt the @a payto_uri when hashing
* @param merch_pub master public key of the merchant
* @param merch_sig signature of the merchant
* @return #GNUNET_OK if signature is valid
*/
enum GNUNET_GenericReturnValue
TALER_merchant_wire_signature_check (
const char *payto_uri,
const struct TALER_WireSalt *salt,
const struct TALER_MerchantPublicKeyP *merch_pub,
const struct TALER_MerchantSignatureP *merch_sig)
{
struct TALER_MasterWireDetailsPS wd = {
.purpose.purpose = htonl (TALER_SIGNATURE_MERCHANT_WIRE_DETAILS),
.purpose.size = htonl (sizeof (wd))
};
TALER_merchant_wire_signature_hash (payto_uri,
salt,
&wd.h_wire_details);
return GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_MERCHANT_WIRE_DETAILS,
&wd,
&merch_sig->eddsa_sig,
&merch_pub->eddsa_pub);
}
/**
* Create a signed wire statement for the given account. (Not yet used anywhere.)
*
* @param payto_uri account specification
* @param salt the salt used to salt the @a payto_uri when hashing
* @param merch_priv private key to sign with
* @param[out] merch_sig where to write the signature
*/
void
TALER_merchant_wire_signature_make (
const char *payto_uri,
const struct TALER_WireSalt *salt,
const struct TALER_MerchantPrivateKeyP *merch_priv,
struct TALER_MerchantSignatureP *merch_sig)
{
struct TALER_MasterWireDetailsPS wd = {
.purpose.purpose = htonl (TALER_SIGNATURE_MERCHANT_WIRE_DETAILS),
.purpose.size = htonl (sizeof (wd))
};
TALER_merchant_wire_signature_hash (payto_uri,
salt,
&wd.h_wire_details);
GNUNET_CRYPTO_eddsa_sign (&merch_priv->eddsa_priv,
&wd,
&merch_sig->eddsa_sig);
}
/* end of crypto_wire.c */
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