/* Only does SIGHASH_ALL */
static void sha256_tx_one_input(struct bitcoin_tx *tx,
size_t input_num,
const u8 *script, size_t script_len,
struct sha256_double *hash)
{
struct sha256_ctx ctx = SHA256_INIT;
size_t i;
assert(input_num < tx->input_count);
/* You must have all inputs zeroed to start. */
for (i = 0; i < tx->input_count; i++)
assert(tx->input[i].script_length == 0);
tx->input[input_num].script_length = script_len;
tx->input[input_num].script = cast_const(u8 *, script);
sha256_init(&ctx);
sha256_tx_for_sig(&ctx, tx, input_num);
sha256_le32(&ctx, SIGHASH_ALL);
sha256_double_done(&ctx, hash);
/* Reset it for next time. */
tx->input[input_num].script_length = 0;
tx->input[input_num].script = NULL;
}
void sha256_tx_for_sig(struct sha256_double *h, const struct bitcoin_tx *tx,
unsigned int input_num, enum sighash_type stype,
const u8 *witness_script)
{
size_t i;
struct sha256_ctx ctx = SHA256_INIT;
/* We only support this. */
assert(stype == SIGHASH_ALL);
/* Caller should zero-out other scripts for signing! */
assert(input_num < tx->input_count);
for (i = 0; i < tx->input_count; i++)
if (i != input_num)
assert(tx->input[i].script_length == 0);
if (witness_script) {
/* BIP143 hashing if OP_CHECKSIG is inside witness. */
hash_for_segwit(&ctx, tx, input_num, witness_script);
} else {
/* Otherwise signature hashing never includes witness. */
add_tx(tx, add_sha, &ctx, false);
}
sha256_le32(&ctx, stype);
sha256_double_done(&ctx, h);
}
