taler/exchange
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

theoretically finished implementation of #4840 (/keys cherry picking), but by far not done testing

Browse Source
This commit is contained in:
Christian Grothoff 2017-09-13 01:14:31 +02:00
parent bf3d34efb6
commit 6d7645a99b
No known key found for this signature in database
GPG Key ID: 939E6BE1E29FC3CC
3 changed files with 296 additions and 122 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

175
src/exchange-lib/exchange_api_handle.c
View File

@ -505,6 +505,7 @@ decode_keys_json (const json_t *resp_obj,
enum TALER_EXCHANGE_VersionCompatibility *vc)
{
struct GNUNET_TIME_Absolute list_issue_date;
struct GNUNET_TIME_Absolute last_denom_issue_date;
struct TALER_ExchangeSignatureP sig;
struct TALER_ExchangeKeySetPS ks;
struct GNUNET_HashContext *hash_context;
@ -513,9 +514,6 @@ decode_keys_json (const json_t *resp_obj,
unsigned int revision;
unsigned int current;
memset (key_data,
0,
sizeof (struct TALER_EXCHANGE_Keys));
if (JSON_OBJECT != json_typeof (resp_obj))
return GNUNET_SYSERR;
@ -588,41 +586,23 @@ decode_keys_json (const json_t *resp_obj,
json_object_get (resp_obj,
"signkeys")));
EXITIF (JSON_ARRAY != json_typeof (sign_keys_array));
EXITIF (0 == (key_data->num_sign_keys =
json_array_size (sign_keys_array)));
key_data->sign_keys
= GNUNET_new_array (key_data->num_sign_keys,
struct TALER_EXCHANGE_SigningPublicKey);
index = 0;
json_array_foreach (sign_keys_array, index, sign_key_obj) {
struct TALER_EXCHANGE_SigningPublicKey sk;
bool found = false;
EXITIF (GNUNET_SYSERR ==
parse_json_signkey (&sk,
parse_json_signkey (&key_data->sign_keys[index],
sign_key_obj,
&key_data->master_pub));
for (unsigned int j=0;j<key_data->num_sign_keys;j++)
{
if (0 == memcmp (&sk,
&key_data->sign_keys[j],
sizeof (sk)))
{
found = true;
break;
}
}
if (found)
{
/* 0:0:0 did not support /keys cherry picking */
GNUNET_break_op (0 == current);
continue;
}
if (key_data->sign_keys_size == key_data->num_sign_keys)
GNUNET_array_grow (key_data->sign_keys,
key_data->sign_keys_size,
key_data->sign_keys_size * 2 + 2);
key_data->sign_keys[key_data->num_sign_keys++] = sk;
}
}
/* parse the denomination keys */
/* parse the denomination keys, merging with the
possibly EXISTING array as required (/keys cherry picking) */
last_denom_issue_date.abs_value_us = 0LLU;
{
json_t *denom_keys_array;
json_t *denom_key_obj;
@ -632,14 +612,11 @@ decode_keys_json (const json_t *resp_obj,
json_object_get (resp_obj, "denoms")));
EXITIF (JSON_ARRAY != json_typeof (denom_keys_array));
key_data->denom_keys = GNUNET_new_array (key_data->num_denom_keys,
struct TALER_EXCHANGE_DenomPublicKey);
index = 0;
json_array_foreach (denom_keys_array, index, denom_key_obj) {
struct TALER_EXCHANGE_DenomPublicKey dk;
bool found = false;
EXITIF (GNUNET_SYSERR ==
parse_json_denomkey (&dk,
denom_key_obj,
@ -658,44 +635,72 @@ decode_keys_json (const json_t *resp_obj,
if (found)
{
/* 0:0:0 did not support /keys cherry picking */
GNUNET_break_op (0 == current);
GNUNET_break_op (0 == current);
continue;
}
if (key_data->denom_keys_size == key_data->num_denom_keys)
GNUNET_array_grow (key_data->denom_keys,
key_data->denom_keys_size,
key_data->denom_keys_size * 2 + 2);
key_data->denom_keys[key_data->num_denom_keys++] = dk;
}
key_data->denom_keys[key_data->num_denom_keys++] = dk;
/* Update "last_denom_issue_date" */
last_denom_issue_date
= GNUNET_TIME_absolute_max (last_denom_issue_date,
dk.valid_from);
};
}
key_data->last_denom_issue_date = last_denom_issue_date;
/* parse the auditor information */
{
json_t *auditors_array;
json_t *auditor_info;
unsigned int len;
unsigned int index;
EXITIF (NULL == (auditors_array =
json_object_get (resp_obj, "auditors")));
EXITIF (JSON_ARRAY != json_typeof (auditors_array));
len = json_array_size (auditors_array);
if (0 != len)
{
key_data->auditors = GNUNET_new_array (len,
struct TALER_EXCHANGE_AuditorInformation);
index = 0;
json_array_foreach (auditors_array, index, auditor_info) {
EXITIF (GNUNET_SYSERR ==
parse_json_auditor (&key_data->auditors[index],
auditor_info,
key_data));
/* Merge with the existing auditor information we have (/keys cherry picking) */
index = 0;
json_array_foreach (auditors_array, index, auditor_info) {
struct TALER_EXCHANGE_AuditorInformation ai;
bool found = false;
EXITIF (GNUNET_SYSERR ==
parse_json_auditor (&ai,
auditor_info,
key_data));
for (unsigned int j=0;j<key_data->num_auditors;j++)
{
struct TALER_EXCHANGE_AuditorInformation *aix = &key_data->auditors[j];
if (0 == memcmp (&ai.auditor_pub,
&aix->auditor_pub,
sizeof (struct TALER_AuditorPublicKeyP)))
{
found = true;
/* Merge denomination key signatures of downloaded /keys into existing
auditor information 'aix'. */
GNUNET_array_grow (aix->denom_keys,
aix->num_denom_keys,
aix->num_denom_keys + ai.num_denom_keys);
memcpy (&aix->denom_keys[aix->num_denom_keys - ai.num_denom_keys],
ai.denom_keys,
ai.num_denom_keys * sizeof (struct TALER_EXCHANGE_DenomPublicKey *));
break;
}
}
key_data->num_auditors = len;
}
if (found)
continue; /* we are done */
if (key_data->auditors_size == key_data->num_auditors)
GNUNET_array_grow (key_data->auditors,
key_data->auditors_size,
key_data->auditors_size * 2 + 2);
key_data->auditors[key_data->num_auditors++] = ai;
};
}
key_data->last_issue_date = list_issue_date;
/* Validate signature... */
ks.purpose.size = htonl (sizeof (ks));
ks.purpose.purpose = htonl (TALER_SIGNATURE_EXCHANGE_KEY_SET);
@ -729,7 +734,7 @@ static void
free_key_data (struct TALER_EXCHANGE_Keys *key_data)
{
GNUNET_array_grow (key_data->sign_keys,
key_data->sign_keys_size,
key_data->num_sign_keys,
0);
for (unsigned int i=0;i<key_data->num_denom_keys;i++)
GNUNET_CRYPTO_rsa_public_key_free (key_data->denom_keys[i].key.rsa_public_key);
@ -744,7 +749,7 @@ free_key_data (struct TALER_EXCHANGE_Keys *key_data)
GNUNET_free (key_data->auditors[i].auditor_url);
}
GNUNET_array_grow (key_data->auditors,
key_data->num_auditors,
key_data->auditors_size,
0);
GNUNET_free_non_null (key_data->version);
key_data->version = NULL;
@ -814,6 +819,47 @@ keys_completed_cb (void *cls,
response_code = 0;
break;
}
memset (&kd,
0,
sizeof (struct TALER_EXCHANGE_Keys));
/* We keep the denomination keys and auditor signatures from the
previous iteration (/keys cherry picking) */
kd.num_denom_keys = kd_old.num_denom_keys;
kd.denom_keys = GNUNET_new_array (kd.num_denom_keys,
struct TALER_EXCHANGE_DenomPublicKey);
/* First make a shallow copy, we then need another pass for the RSA key... */
memcpy (kd.denom_keys,
kd_old.denom_keys,
kd_old.num_denom_keys * sizeof (struct TALER_EXCHANGE_DenomPublicKey));
for (unsigned int i=0;i<kd_old.num_denom_keys;i++)
kd.denom_keys[i].key.rsa_public_key
= GNUNET_CRYPTO_rsa_public_key_dup (kd_old.denom_keys[i].key.rsa_public_key);
kd.num_auditors = kd_old.num_auditors;
kd.auditors = GNUNET_new_array (kd.num_auditors,
struct TALER_EXCHANGE_AuditorInformation);
/* Now the necessary deep copy... */
for (unsigned int i=0;i<kd_old.num_auditors;i++)
{
const struct TALER_EXCHANGE_AuditorInformation *aold = &kd_old.auditors[i];
struct TALER_EXCHANGE_AuditorInformation *anew = &kd.auditors[i];
anew->auditor_pub = aold->auditor_pub;
anew->auditor_url = GNUNET_strdup (aold->auditor_url);
GNUNET_array_grow (anew->denom_keys,
anew->num_denom_keys,
aold->num_denom_keys);
for (unsigned int j=0;j<aold->num_denom_keys;j++)
{
/* offsets will map 1:1 */
unsigned int off = kd_old.denom_keys - aold->denom_keys[j];
GNUNET_assert (off < kd_old.num_denom_keys);
anew->denom_keys[j] = &kd.denom_keys[off];
}
}
if (GNUNET_OK !=
decode_keys_json (resp_obj,
&kd,
@ -953,7 +999,6 @@ parse_date_string (const char *date,
time_t t;
char day[4];
char mon[4];
unsigned int i;
unsigned int mday;
unsigned int year;
unsigned int h;
@ -977,11 +1022,11 @@ parse_date_string (const char *date,
now.tm_min = m;
now.tm_sec = s;
now.tm_wday = 7;
for (i=0;i<7;i++)
for (unsigned int i=0;i<7;i++)
if (0 == strcasecmp (days[i], day))
now.tm_wday = i;
now.tm_mon = 12;
for (i=0;i<12;i++)
for (unsigned int i=0;i<12;i++)
if (0 == strcasecmp (mons[i], mon))
now.tm_mon = i;
if ( (7 == now.tm_wday) ||
@ -1091,7 +1136,7 @@ request_keys (struct TALER_EXCHANGE_Handle *exchange)
GNUNET_asprintf (&arg,
"/keys?last_issue_date=%llu",
(unsigned long long) exchange->key_data.last_issue_date.abs_value_us);
(unsigned long long) exchange->key_data.last_denom_issue_date.abs_value_us);
kr->url = MAH_path_to_url (exchange,
arg);
GNUNET_free (arg);
@ -1172,11 +1217,10 @@ TALER_EXCHANGE_test_signing_key (const struct TALER_EXCHANGE_Keys *keys,
const struct TALER_ExchangePublicKeyP *pub)
{
struct GNUNET_TIME_Absolute now;
unsigned int i;
/* we will check using a tolerance of 1h for the time */
now = GNUNET_TIME_absolute_get ();
for (i=0;i<keys->num_sign_keys;i++)
for (unsigned int i=0;i<keys->num_sign_keys;i++)
if ( (keys->sign_keys[i].valid_from.abs_value_us <= now.abs_value_us + 60 * 60 * 1000LL * 1000LL) &&
(keys->sign_keys[i].valid_until.abs_value_us > now.abs_value_us - 60 * 60 * 1000LL * 1000LL) &&
(0 == memcmp (pub,
@ -1199,9 +1243,7 @@ const struct TALER_EXCHANGE_DenomPublicKey *
TALER_EXCHANGE_get_denomination_key (const struct TALER_EXCHANGE_Keys *keys,
const struct TALER_DenominationPublicKey *pk)
{
unsigned int i;
for (i=0;i<keys->num_denom_keys;i++)
for (unsigned int i=0;i<keys->num_denom_keys;i++)
if (0 == GNUNET_CRYPTO_rsa_public_key_cmp (pk->rsa_public_key,
keys->denom_keys[i].key.rsa_public_key))
return &keys->denom_keys[i];
@ -1220,9 +1262,7 @@ const struct TALER_EXCHANGE_DenomPublicKey *
TALER_EXCHANGE_get_denomination_key_by_hash (const struct TALER_EXCHANGE_Keys *keys,
const struct GNUNET_HashCode *hc)
{
unsigned int i;
for (i=0;i<keys->num_denom_keys;i++)
for (unsigned int i=0;i<keys->num_denom_keys;i++)
if (0 == memcmp (hc,
&keys->denom_keys[i].h_key,
sizeof (struct GNUNET_HashCode)))
@ -1260,5 +1300,4 @@ TALER_EXCHANGE_get_keys_raw (struct TALER_EXCHANGE_Handle *exchange)
}
/* end of exchange_api_handle.c */

218
src/exchange/taler-exchange-httpd_keystate.c
View File

@ -55,29 +55,25 @@
struct TEH_KS_StateHandle
{
/**
* JSON array with denomination keys. (Currently not really used
* after initialization.)
* JSON array with denomination keys.
*/
json_t *denom_keys_array;
/**
* JSON array with signing keys. (Currently not really used
* after initialization.)
*/
json_t *sign_keys_array;
/**
* JSON array with auditor information. (Currently not really used
* after initialization.)
* JSON array with auditor information.
*/
json_t *auditors_array;
/**
* JSON array with revoked denomination keys. (Currently not really used
* after initialization).
* JSON array with revoked denomination keys.
*/
json_t *payback_array;
/**
* JSON array with signing keys.
*/
json_t *sign_keys_array;
/**
* Cached JSON text that the exchange will send for a "/keys" request.
* Includes our @e TEH_master_public_key public key, the signing and
@ -213,6 +209,97 @@ denom_key_issue_to_json (const struct TALER_DenominationPublicKey *pk,
}
/**
* Closure for #denom_keys_to_json().
*/
struct ResponseBuilderContext
{
/**
* JSON array with denomination keys.
*/
json_t *denom_keys_array;
/**
* JSON array with auditor signatures.
*/
json_t *auditors_array;
/**
* Keys after what issue date do we care about?
*/
struct GNUNET_TIME_Absolute last_issue_date;
/**
* Flag set to #GNUNET_SYSERR on internal errors
*/
int error;
};
/**
* Add denomination keys past the "last_issue_date" to the
* "denom_keys_array".
*
* @param cls a `struct ResponseBuilderContext`
* @param key hash of the denomination key
* @param value a `struct TALER_EXCHANGEDB_DenominationKeyIssueInformation`
* @return #GNUNET_OK (continue to iterate)
*/
static int
denom_keys_to_json (void *cls,
const struct GNUNET_HashCode *key,
void *value)
{
struct ResponseBuilderContext *rbc = cls;
struct TALER_EXCHANGEDB_DenominationKeyIssueInformation *dki = value;
if (rbc->last_issue_date.abs_value_us >=
GNUNET_TIME_absolute_ntoh (dki->issue.properties.start).abs_value_us)
{
/* remove matching entry from 'auditors_array' */
size_t off;
json_t *val;
json_t *kval;
kval = GNUNET_JSON_from_data_auto (key);
json_array_foreach (rbc->auditors_array, off, val) {
size_t ioff;
json_t *dkv;
json_t *dka = json_object_get (val,
"denomination_keys");
if (NULL == dka)
{
GNUNET_break (0);
continue;
}
json_array_foreach (dka, ioff, dkv) {
json_t *ival = json_object_get (dkv,
"denom_pub_h");
if (NULL == ival)
{
GNUNET_break (0);
continue;
}
if (json_equal (ival, kval))
{
json_array_remove (dka,
ioff);
break;
}
};
};
return GNUNET_OK; /* skip, key known to client */
}
if (0 !=
json_array_append_new (rbc->denom_keys_array,
denom_key_issue_to_json (&dki->denom_pub,
&dki->issue)))
rbc->error = GNUNET_SYSERR;
return GNUNET_OK;
}
/**
* Get the relative time value that describes how
* far in the future do we want to provide coin keys.
@ -325,7 +412,7 @@ struct AddRevocationContext
/**
* Execute transaction to add revocations.
* Execute transaction to add revocations.
*
* @param cls closure with the `struct AddRevocationContext *`
* @param connection NULL
@ -340,7 +427,7 @@ add_revocations_transaction (void *cls,
int *mhd_ret)
{
struct AddRevocationContext *arc = cls;
return TEH_plugin->insert_denomination_revocation (TEH_plugin->cls,
session,
&arc->dki->issue.properties.denom_hash,
@ -349,7 +436,7 @@ add_revocations_transaction (void *cls,
/**
* Execute transaction to add a denomination to the DB.
* Execute transaction to add a denomination to the DB.
*
* @param cls closure with the `const struct TALER_EXCHANGEDB_DenominationKeyIssueInformation *`
* @param connection NULL
@ -432,7 +519,7 @@ reload_keys_denom_iter (void *cls,
if (NULL != revocation_master_sig)
{
struct AddRevocationContext arc;
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Adding denomination key `%s' to revocation set\n",
alias);
@ -454,9 +541,9 @@ reload_keys_denom_iter (void *cls,
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Giving up, this is fatal. Committing suicide via SIGTERM.\n");
handle_signal (SIGTERM);
return GNUNET_SYSERR;
return GNUNET_SYSERR;
}
GNUNET_assert (0 ==
json_array_append_new (ctx->payback_array,
GNUNET_JSON_from_data_auto (&dki->issue.properties.denom_hash)));
@ -478,8 +565,6 @@ reload_keys_denom_iter (void *cls,
GNUNET_CRYPTO_hash_context_read (ctx->hash_context,
&denom_key_hash,
sizeof (struct GNUNET_HashCode));
if (GNUNET_OK !=
TEH_DB_run_transaction (NULL,
NULL,
@ -487,9 +572,9 @@ reload_keys_denom_iter (void *cls,
(void *) dki))
{
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Giving up, this is fatal. Committing suicide via SIGTERM.\n");
"Could not persist denomination key in DB. Committing suicide via SIGTERM.\n");
handle_signal (SIGTERM);
return GNUNET_SYSERR;
return GNUNET_SYSERR;
}
res = store_in_map (ctx->denomkey_map,
@ -893,10 +978,9 @@ TEH_KS_acquire_ (const char *location)
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"No valid signing key found!\n");
keys = json_pack ("{s:s, s:o, s:o, s:o, s:o, s:o, s:o, s:o, s:o}",
keys = json_pack ("{s:s, s:o, s:O, s:o, s:O, s:O, s:o, s:o, s:o}",
"version", TALER_PROTOCOL_VERSION,
"master_public_key",
GNUNET_JSON_from_data_auto (&TEH_master_public_key),
"master_public_key", GNUNET_JSON_from_data_auto (&TEH_master_public_key),
"signkeys", key_state->sign_keys_array,
"denoms", key_state->denom_keys_array,
"payback", key_state->payback_array,
@ -905,10 +989,7 @@ TEH_KS_acquire_ (const char *location)
"eddsa_pub", GNUNET_JSON_from_data_auto (&key_state->current_sign_key_issue.issue.signkey_pub),
"eddsa_sig", GNUNET_JSON_from_data_auto (&sig));
GNUNET_assert (NULL != keys);
key_state->auditors_array = NULL;
key_state->sign_keys_array = NULL;
key_state->denom_keys_array = NULL;
key_state->payback_array = NULL;
key_state->keys_json = json_dumps (keys,
JSON_INDENT (2));
GNUNET_assert (NULL != key_state->keys_json);
@ -1282,7 +1363,7 @@ TEH_KS_handler_keys (struct TEH_RequestHandler *rh,
if (NULL != have)
{
unsigned long long haven;
if (1 !=
sscanf (have,
"%llu",
@ -1299,26 +1380,75 @@ TEH_KS_handler_keys (struct TEH_RequestHandler *rh,
{
last_issue_date.abs_value_us = 0LLU;
}
key_state = TEH_KS_acquire ();
/* FIXME: #4840: compute /keys delta from last_issue_date */
(void) last_issue_date;
comp = MHD_NO;
if (NULL != key_state->keys_jsonz)
comp = TEH_RESPONSE_can_compress (connection);
if (MHD_YES == comp)
if (0LLU != last_issue_date.abs_value_us)
{
json = key_state->keys_jsonz;
json_len = key_state->keys_jsonz_size;
/* Generate incremental response */
struct ResponseBuilderContext rbc;
rbc.error = GNUNET_NO;
rbc.denom_keys_array = json_array ();
rbc.auditors_array = json_deep_copy (key_state->auditors_array);
rbc.last_issue_date = last_issue_date;
GNUNET_CONTAINER_multihashmap_iterate (key_state->denomkey_map,
&denom_keys_to_json,
&rbc);
if (GNUNET_NO == rbc.error)
{
json_t *keys;
keys = json_pack ("{s:s, s:o, s:O, s:o, s:O, s:o, s:o}",
"version", TALER_PROTOCOL_VERSION,
"master_public_key", GNUNET_JSON_from_data_auto (&TEH_master_public_key),
"signkeys", key_state->sign_keys_array,
"denoms", rbc.denom_keys_array,
"payback", key_state->payback_array,
"auditors", rbc.auditors_array,
"list_issue_date", GNUNET_JSON_from_time_abs (key_state->reload_time));
rbc.denom_keys_array = NULL;
rbc.auditors_array = NULL;
json = json_dumps (keys,
JSON_INDENT (2));
json_decref (keys);
json_len = strlen (json);
if (TEH_RESPONSE_can_compress (connection))
comp = TEH_RESPONSE_body_compress ((void **) &json,
&json_len);
response = MHD_create_response_from_buffer (json_len,
json,
MHD_RESPMEM_MUST_FREE);
}
else
{
/* Try to salvage the situation by returning full reply */
GNUNET_break (0);
last_issue_date.abs_value_us = 0LLU;
}
if (NULL != rbc.denom_keys_array)
json_decref (rbc.denom_keys_array);
if (NULL != rbc.auditors_array)
json_decref (rbc.auditors_array);
}
else
if (0LLU == last_issue_date.abs_value_us)
{
json = key_state->keys_json;
json_len = strlen (key_state->keys_json);
/* Generate full response */
comp = MHD_NO;
if (NULL != key_state->keys_jsonz)
comp = TEH_RESPONSE_can_compress (connection);
if (MHD_YES == comp)
{
json = key_state->keys_jsonz;
json_len = key_state->keys_jsonz_size;
}
else
{
json = key_state->keys_json;
json_len = strlen (key_state->keys_json);
}
response = MHD_create_response_from_buffer (json_len,
json,
MHD_RESPMEM_MUST_COPY);
}
response = MHD_create_response_from_buffer (json_len,
json,
MHD_RESPMEM_MUST_COPY);
TEH_KS_release (key_state);
if (NULL == response)
{

25
src/include/taler_exchange_service.h
View File

@ -206,12 +206,17 @@ struct TALER_EXCHANGE_Keys
char *version;
/**
* Timestamp indicating the /keys generation. Monotonically
* increasing. Used to fetch /keys incrementally. Set from
* the "list_issue_date" timestamp of /keys.
* Timestamp indicating the /keys generation.
*/
struct GNUNET_TIME_Absolute last_issue_date;
struct GNUNET_TIME_Absolute list_issue_date;
/**
* Timestamp indicating the creation time of the last
* denomination key in /keys.
* Used to fetch /keys incrementally.
*/
struct GNUNET_TIME_Absolute last_denom_issue_date;
/**
* Length of the @e sign_keys array (number of valid entries).
*/
@ -228,9 +233,9 @@ struct TALER_EXCHANGE_Keys
unsigned int num_auditors;
/**
* Actual length of the @e sign_keys array (size of allocation).
* Actual length of the @e auditors array (size of allocation).
*/
unsigned int sign_keys_size;
unsigned int auditors_size;
/**
* Actual length of the @e denom_keys array (size of allocation).
@ -240,7 +245,7 @@ struct TALER_EXCHANGE_Keys
};
/**
/**
* How compatible are the protocol version of the exchange and this
* client? The bits (1,2,4) can be used to test if the exchange's
* version is incompatible, older or newer respectively.
@ -280,7 +285,7 @@ enum TALER_EXCHANGE_VersionCompatibility
/**
* The exchange is too recent for this implementation.
*/
TALER_EXCHANGE_VC_INCOMPATIBLE_NEWER
TALER_EXCHANGE_VC_INCOMPATIBLE_NEWER
= TALER_EXCHANGE_VC_INCOMPATIBLE
| TALER_EXCHANGE_VC_NEWER,
@ -288,7 +293,7 @@ enum TALER_EXCHANGE_VersionCompatibility
* We could not even parse the version data.
*/
TALER_EXCHANGE_VC_PROTOCOL_ERROR = 8
};