1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
|
/*
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);
}
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;
struct TALER_CsNonce 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_deep_copy (&md->melted_coin.pub_key,
&rd->melt_pk.key);
TALER_denom_sig_deep_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];
if (alg_values[j].cipher != rd->fresh_pks[j].key.cipher)
{
GNUNET_break (0);
TALER_EXCHANGE_free_melt_data_ (md);
return GNUNET_SYSERR;
}
if (TALER_DENOMINATION_CS == alg_values[j].cipher)
{
uses_cs = true;
TALER_cs_refresh_nonce_derive (
rms,
j,
&nonces[j]);
}
TALER_denom_pub_deep_copy (&fcd->fresh_pk,
&rd->fresh_pks[j].key);
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 TALER_DenominationBlindingKeyP *bks = &fcd->bks[i];
struct TALER_PlanchetDetail pd;
struct TALER_CoinPubHashP c_hash;
struct TALER_AgeCommitmentHash *ach = 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);
/* Handle age commitment, if present */
if (NULL != md->melted_coin.age_commitment_proof)
{
/* We use the first 8 bytes of the trans_sec to generate a new age
* commitment */
uint64_t age_seed = (uint64_t) trans_sec.key.bits[0]
| (uint64_t) trans_sec.key.bits[1] << 32;
fcd->age_commitment_proof[i] = GNUNET_new (struct
TALER_AgeCommitmentProof);
ach = GNUNET_new (struct TALER_AgeCommitmentHash);
GNUNET_assert (GNUNET_OK ==
TALER_age_commitment_derive (
md->melted_coin.age_commitment_proof,
age_seed,
fcd->age_commitment_proof[i]));
TALER_age_commitment_hash (
&fcd->age_commitment_proof[i]->commitment,
ach);
}
if (TALER_DENOMINATION_CS == alg_values[j].cipher)
pd.blinded_planchet.details.cs_blinded_planchet.nonce = nonces[j];
if (GNUNET_OK !=
TALER_planchet_prepare (&fcd->fresh_pk,
&alg_values[j],
bks,
coin_priv,
ach,
&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;
}
|
