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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)
{
for (unsigned int i = 0; i < TALER_CNC_KAPPA; i++)
{
struct TALER_RefreshCoinData *rcds = md->rcd[i];
if (NULL == rcds)
continue;
for (unsigned int j = 0; j < md->num_fresh_coins; j++)
TALER_blinded_planchet_free (&rcds[j].blinded_planchet);
GNUNET_free (rcds);
}
TALER_denom_pub_free (&md->melted_coin.pub_key);
TALER_denom_sig_free (&md->melted_coin.sig);
if (NULL != md->fcds)
{
for (unsigned int j = 0; j<md->num_fresh_coins; j++)
{
struct FreshCoinData *fcd = &md->fcds[j];
TALER_denom_pub_free (&fcd->fresh_pk);
for (size_t i = 0; i < TALER_CNC_KAPPA; i++)
{
TALER_age_commitment_proof_free (fcd->age_commitment_proofs[i]);
GNUNET_free (fcd->age_commitment_proofs[i]);
}
}
GNUNET_free (md->fcds);
}
/* Finally, clean up a bit... */
GNUNET_CRYPTO_zero_keys (md,
sizeof (struct MeltData));
}
enum GNUNET_GenericReturnValue
TALER_EXCHANGE_get_melt_data_ (
const struct TALER_RefreshMasterSecretP *rms,
const struct TALER_EXCHANGE_RefreshData *rd,
const struct TALER_ExchangeWithdrawValues *alg_values,
struct MeltData *md)
{
struct TALER_Amount total;
struct TALER_CoinSpendPublicKeyP coin_pub;
union GNUNET_CRYPTO_BlindSessionNonce nonces[rd->fresh_pks_len];
bool uses_cs = false;
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.fees.refresh;
md->melted_coin.original_value = rd->melt_pk.value;
md->melted_coin.expire_deposit = rd->melt_pk.expire_deposit;
md->melted_coin.age_commitment_proof = rd->melt_age_commitment_proof;
md->melted_coin.h_age_commitment = rd->melt_h_age_commitment;
GNUNET_assert (GNUNET_OK ==
TALER_amount_set_zero (rd->melt_amount.currency,
&total));
TALER_denom_pub_copy (&md->melted_coin.pub_key,
&rd->melt_pk.key);
TALER_denom_sig_copy (&md->melted_coin.sig,
&rd->melt_sig);
md->fcds = GNUNET_new_array (md->num_fresh_coins,
struct FreshCoinData);
for (unsigned int j = 0; j<rd->fresh_pks_len; j++)
{
struct FreshCoinData *fcd = &md->fcds[j];
TALER_denom_pub_copy (&fcd->fresh_pk,
&rd->fresh_pks[j].key);
GNUNET_assert (NULL != fcd->fresh_pk.bsign_pub_key);
if (alg_values[j].blinding_inputs->cipher !=
fcd->fresh_pk.bsign_pub_key->cipher)
{
GNUNET_break (0);
TALER_EXCHANGE_free_melt_data_ (md);
return GNUNET_SYSERR;
}
switch (fcd->fresh_pk.bsign_pub_key->cipher)
{
case GNUNET_CRYPTO_BSA_INVALID:
GNUNET_break (0);
TALER_EXCHANGE_free_melt_data_ (md);
return GNUNET_SYSERR;
case GNUNET_CRYPTO_BSA_RSA:
break;
case GNUNET_CRYPTO_BSA_CS:
uses_cs = true;
TALER_cs_refresh_nonce_derive (rms,
j,
&nonces[j].cs_nonce);
break;
}
if ( (0 >
TALER_amount_add (&total,
&total,
&rd->fresh_pks[j].value)) ||
(0 >
TALER_amount_add (&total,
&total,
&rd->fresh_pks[j].fees.withdraw)) )
{
GNUNET_break (0);
TALER_EXCHANGE_free_melt_data_ (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);
return GNUNET_SYSERR;
}
/* build up coins */
for (unsigned int i = 0; i<TALER_CNC_KAPPA; i++)
{
struct TALER_TransferSecretP trans_sec;
TALER_planchet_secret_to_transfer_priv (
rms,
&rd->melt_priv,
i,
&md->transfer_priv[i]);
GNUNET_CRYPTO_ecdhe_key_get_public (
&md->transfer_priv[i].ecdhe_priv,
&md->transfer_pub[i].ecdhe_pub);
TALER_link_derive_transfer_secret (&rd->melt_priv,
&md->transfer_priv[i],
&trans_sec);
md->rcd[i] = GNUNET_new_array (rd->fresh_pks_len,
struct TALER_RefreshCoinData);
for (unsigned int j = 0; j<rd->fresh_pks_len; j++)
{
struct FreshCoinData *fcd = &md->fcds[j];
struct TALER_CoinSpendPrivateKeyP *coin_priv = &fcd->coin_priv;
struct TALER_PlanchetMasterSecretP *ps = &fcd->ps[i];
struct TALER_RefreshCoinData *rcd = &md->rcd[i][j];
union GNUNET_CRYPTO_BlindingSecretP *bks = &fcd->bks[i];
struct TALER_PlanchetDetail pd;
struct TALER_CoinPubHashP c_hash;
struct TALER_AgeCommitmentHash ach;
struct TALER_AgeCommitmentHash *pah = NULL;
TALER_transfer_secret_to_planchet_secret (&trans_sec,
j,
ps);
TALER_planchet_setup_coin_priv (ps,
&alg_values[j],
coin_priv);
TALER_planchet_blinding_secret_create (ps,
&alg_values[j],
bks);
if (NULL != rd->melt_age_commitment_proof)
{
fcd->age_commitment_proofs[i] = GNUNET_new (struct
TALER_AgeCommitmentProof);
GNUNET_assert (GNUNET_OK ==
TALER_age_commitment_derive (
md->melted_coin.age_commitment_proof,
&trans_sec.key,
fcd->age_commitment_proofs[i]));
TALER_age_commitment_hash (
&fcd->age_commitment_proofs[i]->commitment,
&ach);
pah = &ach;
}
if (GNUNET_OK !=
TALER_planchet_prepare (&fcd->fresh_pk,
&alg_values[j],
bks,
&nonces[j],
coin_priv,
pah,
&c_hash,
&pd))
{
GNUNET_break_op (0);
TALER_EXCHANGE_free_melt_data_ (md);
return GNUNET_SYSERR;
}
rcd->blinded_planchet = pd.blinded_planchet;
rcd->dk = &fcd->fresh_pk;
}
}
/* Finally, compute refresh commitment */
{
struct TALER_RefreshCommitmentEntry rce[TALER_CNC_KAPPA];
for (unsigned int i = 0; i<TALER_CNC_KAPPA; i++)
{
rce[i].transfer_pub = md->transfer_pub[i];
rce[i].new_coins = md->rcd[i];
}
TALER_refresh_get_commitment (&md->rc,
TALER_CNC_KAPPA,
uses_cs
? rms
: NULL,
rd->fresh_pks_len,
rce,
&coin_pub,
&rd->melt_amount);
}
return GNUNET_OK;
}
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