def make_btc_block_merkle_tree(blk_txids):
assert len(blk_txids) > 0
digests = blk_txids
while len(digests) > 1:
# The famously broken Satoshi algorithm: if the # of digests at this
# level is odd, double the last one.
if len(digests) % 2:
digests.append(digests[-1].msg)
next_level = []
for i in range(0, len(digests), 2):
next_level.append(cat_sha256d(digests[i], digests[i + 1]))
digests = next_level
return digests[0]
def make_timestamp_from_block_tx(confirmed_tx, block, blockheight):
commitment_tx = confirmed_tx.tx
serialized_tx = commitment_tx.serialize(params={'include_witness': False})
digest = confirmed_tx.tip_timestamp.msg
try:
i = serialized_tx.index(digest)
except ValueError:
assert False, "can't build a block_timestamp from my tx, this is not supposed to happen, exiting"
prefix = serialized_tx[0:i]
suffix = serialized_tx[i + len(digest):]
digest_timestamp = Timestamp(digest)
# Add the commitment ops necessary to go from the digest to the txid op
prefix_stamp = digest_timestamp.ops.add(OpPrepend(prefix))
txid_stamp = cat_sha256d(prefix_stamp, suffix)
assert commitment_tx.GetTxid() == txid_stamp.msg
# Create the txid list, with our commitment txid op in the appropriate
# place
block_txid_stamps = []
for tx in block.vtx:
if tx.GetTxid() != txid_stamp.msg:
block_txid_stamps.append(Timestamp(tx.GetTxid()))
else:
block_txid_stamps.append(txid_stamp)
# Build the merkle tree
merkleroot_stamp = make_btc_block_merkle_tree(block_txid_stamps)
assert merkleroot_stamp.msg == block.hashMerkleRoot
if bitcoin.params.NAME.lower() == "testnet":
attestation = BitcoinTestnetBlockHeaderAttestation(blockheight)
else:
attestation = BitcoinBlockHeaderAttestation(blockheight)
merkleroot_stamp.attestations.add(attestation)
return digest_timestamp