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/*
This file is part of TALER
Copyright (C) 2015-2022 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 lib/exchange_api_refresh_common.c
* @brief Serialization logic shared between melt and reveal steps during refreshing
* @author Christian Grothoff
*/
#include "platform.h"
#include "exchange_api_refresh_common.h"
void
TALER_EXCHANGE_free_melt_data_ (struct MeltData *md)
{
TALER_denom_pub_free (&md->melted_coin.pub_key);
TALER_denom_sig_free (&md->melted_coin.sig);
if (NULL != md->fresh_pks)
{
for (unsigned int i = 0; i<md->num_fresh_coins; i++)
TALER_denom_pub_free (&md->fresh_pks[i]);
GNUNET_free (md->fresh_pks);
}
for (unsigned int i = 0; i<TALER_CNC_KAPPA; i++)
GNUNET_free (md->fresh_coins[i]);
/* Finally, clean up a bit... */
GNUNET_CRYPTO_zero_keys (md,
sizeof (struct MeltData));
}
enum GNUNET_GenericReturnValue
TALER_EXCHANGE_get_melt_data_ (
const struct TALER_PlanchetSecretsP *ps,
const struct TALER_EXCHANGE_RefreshData *rd,
const struct TALER_ExchangeWithdrawValues *alg_values,
struct MeltData *md)
{
struct TALER_Amount total;
struct TALER_CoinSpendPublicKeyP coin_pub;
struct TALER_TransferSecretP trans_sec[TALER_CNC_KAPPA];
struct TALER_RefreshCommitmentEntry rce[TALER_CNC_KAPPA];
GNUNET_CRYPTO_eddsa_key_get_public (&rd->melt_priv.eddsa_priv,
&coin_pub.eddsa_pub);
/* build up melt data structure */
memset (md,
0,
sizeof (*md));
md->num_fresh_coins = rd->fresh_pks_len;
md->melted_coin.coin_priv = rd->melt_priv;
md->melted_coin.melt_amount_with_fee = rd->melt_amount;
md->melted_coin.fee_melt = rd->melt_pk.fee_refresh;
md->melted_coin.original_value = rd->melt_pk.value;
md->melted_coin.expire_deposit = rd->melt_pk.expire_deposit;
GNUNET_assert (GNUNET_OK ==
TALER_amount_set_zero (rd->melt_amount.currency,
&total));
TALER_denom_pub_deep_copy (&md->melted_coin.pub_key,
&rd->melt_pk.key);
TALER_denom_sig_deep_copy (&md->melted_coin.sig,
&rd->melt_sig);
md->fresh_pks = GNUNET_new_array (rd->fresh_pks_len,
struct TALER_DenominationPublicKey);
for (unsigned int i = 0; i<rd->fresh_pks_len; i++)
{
TALER_denom_pub_deep_copy (&md->fresh_pks[i],
&rd->fresh_pks[i].key);
if ( (0 >
TALER_amount_add (&total,
&total,
&rd->fresh_pks[i].value)) ||
(0 >
TALER_amount_add (&total,
&total,
&rd->fresh_pks[i].fee_withdraw)) )
{
GNUNET_break (0);
TALER_EXCHANGE_free_melt_data_ (md);
memset (md,
0,
sizeof (*md));
return GNUNET_SYSERR;
}
}
/* verify that melt_amount is above total cost */
if (1 ==
TALER_amount_cmp (&total,
&rd->melt_amount) )
{
/* Eh, this operation is more expensive than the
@a melt_amount. This is not OK. */
GNUNET_break (0);
TALER_EXCHANGE_free_melt_data_ (md);
memset (md,
0,
sizeof (*md));
return GNUNET_SYSERR;
}
/* build up coins */
for (unsigned int i = 0; i<TALER_CNC_KAPPA; i++)
{
TALER_planchet_secret_to_transfer_priv (
ps,
i,
&md->melted_coin.transfer_priv[i]);
GNUNET_CRYPTO_ecdhe_key_get_public (
&md->melted_coin.transfer_priv[i].ecdhe_priv,
&rce[i].transfer_pub.ecdhe_pub);
TALER_link_derive_transfer_secret (&rd->melt_priv,
&md->melted_coin.transfer_priv[i],
&trans_sec[i]);
md->fresh_coins[i] = GNUNET_new_array (rd->fresh_pks_len,
struct TALER_PlanchetSecretsP);
rce[i].new_coins = GNUNET_new_array (rd->fresh_pks_len,
struct TALER_RefreshCoinData);
for (unsigned int j = 0; j<rd->fresh_pks_len; j++)
{
struct TALER_PlanchetSecretsP *fc = &md->fresh_coins[i][j];
struct TALER_RefreshCoinData *rcd = &rce[i].new_coins[j];
struct TALER_PlanchetDetail pd;
struct TALER_CoinPubHash c_hash;
struct TALER_CoinSpendPrivateKeyP coin_priv;
union TALER_DenominationBlindingKeyP bks;
TALER_transfer_secret_to_planchet_secret (&trans_sec[i],
j,
fc);
TALER_planchet_setup_coin_priv (fc,
&alg_values[j],
&coin_priv);
TALER_planchet_blinding_secret_create (fc,
&alg_values[j],
&bks);
/* Note: we already did this for the /csr request,
so this computation is redundant, and here additionally
repeated KAPPA times. Could be avoided with slightly
more bookkeeping in the future */
TALER_cs_refresh_nonce_derive (
ps,
j,
&pd.blinded_planchet.details.cs_blinded_planchet.nonce);
if (GNUNET_OK !=
TALER_planchet_prepare (&md->fresh_pks[j],
&alg_values[j],
&bks,
&coin_priv,
&c_hash,
&pd))
{
GNUNET_break_op (0);
TALER_EXCHANGE_free_melt_data_ (md);
memset (md,
0,
sizeof (*md));
return GNUNET_SYSERR;
}
rcd->dk = &md->fresh_pks[j];
rcd->blinded_planchet = pd.blinded_planchet;
}
}
/* Compute refresh commitment */
TALER_refresh_get_commitment (&md->rc,
TALER_CNC_KAPPA,
rd->fresh_pks_len,
rce,
&coin_pub,
&rd->melt_amount);
for (unsigned int i = 0; i < TALER_CNC_KAPPA; i++)
{
for (unsigned int j = 0; j < rd->fresh_pks_len; j++)
TALER_blinded_planchet_free (&rce[i].new_coins[j].blinded_planchet);
GNUNET_free (rce[i].new_coins);
}
return GNUNET_OK;
}
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