void bp_tx_sighash(bu256_t *hash, const cstring *scriptCode,
const struct bp_tx *txTo, unsigned int nIn,
int nHashType)
{
if (nIn >= txTo->vin->len) {
// nIn out of range
bu256_set_u64(hash, 1);
return;
}
// Check for invalid use of SIGHASH_SINGLE
if ((nHashType & 0x1f) == SIGHASH_SINGLE) {
if (nIn >= txTo->vout->len) {
// nOut out of range
bu256_set_u64(hash, 1);
return;
}
}
cstring *s = cstr_new_sz(512);
// Serialize only the necessary parts of the transaction being signed
bp_tx_sigserializer(s, scriptCode, txTo, nIn, nHashType);
ser_s32(s, nHashType);
bu_Hash((unsigned char *) hash, s->str, s->len);
cstr_free(s, true);
}
void btc_tx_serialize(cstring* s, const btc_tx* tx)
{
ser_s32(s, tx->version);
ser_varlen(s, tx->vin ? tx->vin->len : 0);
unsigned int i;
if (tx->vin) {
for (i = 0; i < tx->vin->len; i++) {
btc_tx_in* tx_in;
tx_in = vector_idx(tx->vin, i);
btc_tx_in_serialize(s, tx_in);
}
}
ser_varlen(s, tx->vout ? tx->vout->len : 0);
if (tx->vout) {
for (i = 0; i < tx->vout->len; i++) {
btc_tx_out* tx_out;
tx_out = vector_idx(tx->vout, i);
btc_tx_out_serialize(s, tx_out);
}
}
ser_u32(s, tx->locktime);
}
static void bp_tx_calc_sighash(bu256_t *hash, const struct bp_tx *tx,
int nHashType)
{
/* TODO: introduce hashing-only serialization mode */
GString *s = g_string_sized_new(512);
ser_bp_tx(s, tx);
ser_s32(s, nHashType);
bu_Hash((unsigned char *) hash, s->str, s->len);
g_string_free(s, TRUE);
}
btc_bool btc_tx_sighash(const btc_tx* tx_to, const cstring* fromPubKey, unsigned int in_num, int hashtype, uint8_t* hash)
{
if (in_num >= tx_to->vin->len)
return false;
btc_bool ret = true;
btc_tx* tx_tmp = btc_tx_new();
btc_tx_copy(tx_tmp, tx_to);
cstring* new_script = cstr_new_sz(fromPubKey->len);
btc_script_copy_without_op_codeseperator(fromPubKey, new_script);
unsigned int i;
btc_tx_in* tx_in;
for (i = 0; i < tx_tmp->vin->len; i++) {
tx_in = vector_idx(tx_tmp->vin, i);
cstr_resize(tx_in->script_sig, 0);
if (i == in_num)
cstr_append_buf(tx_in->script_sig,
new_script->str,
new_script->len);
}
cstr_free(new_script, true);
/* Blank out some of the outputs */
if ((hashtype & 0x1f) == SIGHASH_NONE) {
/* Wildcard payee */
if (tx_tmp->vout)
vector_free(tx_tmp->vout, true);
tx_tmp->vout = vector_new(1, btc_tx_out_free_cb);
/* Let the others update at will */
for (i = 0; i < tx_tmp->vin->len; i++) {
tx_in = vector_idx(tx_tmp->vin, i);
if (i != in_num)
tx_in->sequence = 0;
}
}
else if ((hashtype & 0x1f) == SIGHASH_SINGLE) {
/* Only lock-in the txout payee at same index as txin */
unsigned int n_out = in_num;
if (n_out >= tx_tmp->vout->len) {
//TODO: set error code
ret = false;
goto out;
}
vector_resize(tx_tmp->vout, n_out + 1);
for (i = 0; i < n_out; i++) {
btc_tx_out* tx_out;
tx_out = vector_idx(tx_tmp->vout, i);
tx_out->value = -1;
if (tx_out->script_pubkey) {
cstr_free(tx_out->script_pubkey, true);
tx_out->script_pubkey = NULL;
}
}
/* Let the others update at will */
for (i = 0; i < tx_tmp->vin->len; i++) {
tx_in = vector_idx(tx_tmp->vin, i);
if (i != in_num)
tx_in->sequence = 0;
}
}
/* Blank out other inputs completely;
not recommended for open transactions */
if (hashtype & SIGHASH_ANYONECANPAY) {
if (in_num > 0)
vector_remove_range(tx_tmp->vin, 0, in_num);
vector_resize(tx_tmp->vin, 1);
}
cstring* s = cstr_new_sz(512);
btc_tx_serialize(s, tx_tmp);
ser_s32(s, hashtype);
sha256_Raw((const uint8_t*)s->str, s->len, hash);
sha256_Raw(hash, 32, hash);
cstr_free(s, true);
out:
btc_tx_free(tx_tmp);
return ret;
}
