static void hash_for_segwit(struct sha256_ctx *ctx,
const struct bitcoin_tx *tx,
unsigned int input_num,
const u8 *witness_script)
{
struct sha256_double h;
/* BIP143:
*
* Double SHA256 of the serialization of:
* 1. nVersion of the transaction (4-byte little endian)
*/
add_le32(tx->version, add_sha, ctx);
/* 2. hashPrevouts (32-byte hash) */
hash_prevouts(&h, tx);
add_sha(&h, sizeof(h), ctx);
/* 3. hashSequence (32-byte hash) */
hash_sequence(&h, tx);
add_sha(&h, sizeof(h), ctx);
/* 4. outpoint (32-byte hash + 4-byte little endian) */
add_sha(&tx->input[input_num].txid, sizeof(tx->input[input_num].txid),
ctx);
add_le32(tx->input[input_num].index, add_sha, ctx);
/* 5. scriptCode of the input (varInt for the length + script) */
add_varint_blob(witness_script, tal_count(witness_script), add_sha, ctx);
/* 6. value of the output spent by this input (8-byte little end) */
add_le64(*tx->input[input_num].amount, add_sha, ctx);
/* 7. nSequence of the input (4-byte little endian) */
add_le32(tx->input[input_num].sequence_number, add_sha, ctx);
/* 8. hashOutputs (32-byte hash) */
hash_outputs(&h, tx);
add_sha(&h, sizeof(h), ctx);
/* 9. nLocktime of the transaction (4-byte little endian) */
add_le32(tx->lock_time, add_sha, ctx);
}
static void hash_prevouts(struct sha256_double *h, const struct bitcoin_tx *tx)
{
struct sha256_ctx ctx;
size_t i;
/* BIP143: If the ANYONECANPAY flag is not set, hashPrevouts is the
* double SHA256 of the serialization of all input
* outpoints */
sha256_init(&ctx);
for (i = 0; i < tx->input_count; i++) {
add_sha(&tx->input[i].txid, sizeof(tx->input[i].txid), &ctx);
add_le32(tx->input[i].index, add_sha, &ctx);
}
sha256_double_done(&ctx, h);
}
int
main()
{
char buf[BUFSIZ];
int state;
char digest[40], *dp;
char *b_end = 0;
int nbytes;
state = NEW_UDIG;
while ((nbytes = _read(buf, sizeof buf)) > 0) {
char *b;
b = buf;
b_end = buf + nbytes;
while (b < b_end) {
char c;
c = *b++;
switch (state) {
/*
* New sha udig always starts with character 's'
*/
case NEW_UDIG:
if (c != 's')
exit(1);
state = SCAN_ALGORITHM_h;
break;
/*
* Scan character 'h'.
*/
case SCAN_ALGORITHM_h:
if (c != 'h')
exit(1);
state = SCAN_ALGORITHM_a;
break;
/*
* Scan character 'a'.
*/
case SCAN_ALGORITHM_a:
if (c != 'a')
exit(1);
state = SCAN_ALGORITHM_colon;
break;
/*
* Scan a colon character.
*/
case SCAN_ALGORITHM_colon:
if (c != ':')
exit(1);
state = SCAN_DIGEST;
dp = digest;
break;
/*
* Scan up to 40 hex characters.
*/
case SCAN_DIGEST:
if (!IS_HEX(c))
exit(1);
*dp++ = c;
if (dp - digest == 40)
state = SCAN_NEW_LINE;
break;
case SCAN_NEW_LINE:
if (c != '\n')
exit(1);
add_sha(digest);
state = NEW_UDIG;
break;
}
}
}
if (state != NEW_UDIG)
exit(1);
exit(b_end ? 0 : 2);
}