def test_verify_proof(self):
claim1_name = 97 # 'a'
claim1_txid = 'bd9fa7ffd57d810d4ce14de76beea29d847b8ac34e8e536802534ecb1ca43b68'
claim1_outpoint = 0
claim1_height = 10
claim1_node_hash = get_hash_for_outpoint(
unhexlify(claim1_txid)[::-1], claim1_outpoint, claim1_height)
claim2_name = 98 # 'b'
claim2_txid = 'ad9fa7ffd57d810d4ce14de76beea29d847b8ac34e8e536802534ecb1ca43b68'
claim2_outpoint = 1
claim2_height = 5
claim2_node_hash = get_hash_for_outpoint(
unhexlify(claim2_txid)[::-1], claim2_outpoint, claim2_height)
to_hash1 = claim1_node_hash
hash1 = double_sha256(to_hash1)
to_hash2 = bytes((claim1_name, )) + hash1 + bytes(
(claim2_name, )) + claim2_node_hash
root_hash = double_sha256(to_hash2)
proof = {
'last takeover height':
claim1_height,
'txhash':
claim1_txid,
'nOut':
claim1_outpoint,
'nodes': [
{
'children': [{
'character': 97
}, {
'character': 98,
'nodeHash': hexlify(claim2_node_hash[::-1])
}]
},
{
'children': []
},
]
}
out = verify_proof(proof, hexlify(root_hash[::-1]), 'a')
self.assertTrue(out)
def get_root_of_merkle_tree(branches, branch_positions, working_branch):
for i, branch in enumerate(branches):
other_branch = unhexlify(branch)[::-1]
other_branch_on_left = bool((branch_positions >> i) & 1)
if other_branch_on_left:
combined = other_branch + working_branch
else:
combined = working_branch + other_branch
working_branch = double_sha256(combined)
return hexlify(working_branch[::-1])
def hash160_to_address(cls, h160):
raw_address = cls.pubkey_address_prefix + h160
return Base58.encode(
bytearray(raw_address + double_sha256(raw_address)[0:4]))
def hash_header(header: bytes) -> bytes:
if header is None:
return b'0' * 64
return hexlify(double_sha256(header)[::-1])
def get_hash_for_outpoint(txhash, nout, height_of_last_takeover):
return double_sha256(
double_sha256(txhash) + double_sha256(str(nout).encode()) +
double_sha256(struct.pack('>Q', height_of_last_takeover)))
def verify_proof(proof, root_hash, name):
previous_computed_hash = None
reverse_computed_name = ''
verified_value = False
for i, node in enumerate(proof['nodes'][::-1]):
found_child_in_chain = False
to_hash = b''
previous_child_character = None
for child in node['children']:
if child['character'] < 0 or child['character'] > 255:
raise InvalidProofError(
"child character not int between 0 and 255")
if previous_child_character:
if previous_child_character >= child['character']:
raise InvalidProofError("children not in increasing order")
previous_child_character = child['character']
to_hash += bytes((child['character'], ))
if 'nodeHash' in child:
if len(child['nodeHash']) != 64:
raise InvalidProofError("invalid child nodeHash")
to_hash += binascii.unhexlify(child['nodeHash'])[::-1]
else:
if previous_computed_hash is None:
raise InvalidProofError("previous computed hash is None")
if found_child_in_chain is True:
raise InvalidProofError(
"already found the next child in the chain")
found_child_in_chain = True
reverse_computed_name += chr(child['character'])
to_hash += previous_computed_hash
if not found_child_in_chain:
if i != 0:
raise InvalidProofError("did not find the alleged child")
if i == 0 and 'txhash' in proof and 'nOut' in proof and 'last takeover height' in proof:
if len(proof['txhash']) != 64:
raise InvalidProofError("txhash was invalid: {}".format(
proof['txhash']))
if not isinstance(proof['nOut'], int):
raise InvalidProofError("nOut was invalid: {}".format(
proof['nOut']))
if not isinstance(proof['last takeover height'], int):
raise InvalidProofError(
'last takeover height was invalid: {}'.format(
proof['last takeover height']))
to_hash += get_hash_for_outpoint(
binascii.unhexlify(proof['txhash'])[::-1], proof['nOut'],
proof['last takeover height'])
verified_value = True
elif 'valueHash' in node:
if len(node['valueHash']) != 64:
raise InvalidProofError("valueHash was invalid")
to_hash += binascii.unhexlify(node['valueHash'])[::-1]
previous_computed_hash = double_sha256(to_hash)
if previous_computed_hash != binascii.unhexlify(root_hash)[::-1]:
raise InvalidProofError("computed hash does not match roothash")
if 'txhash' in proof and 'nOut' in proof:
if not verified_value:
raise InvalidProofError("mismatch between proof claim and outcome")
target = reverse_computed_name[::-1].encode('ISO-8859-1').decode()
if 'txhash' in proof and 'nOut' in proof:
if name != target:
raise InvalidProofError("name did not match proof")
if not name.startswith(target):
raise InvalidProofError("name fragment does not match proof")
return True
def header_hash_to_pow_hash(header_hash: bytes):
header_hash_bytes = unhexlify(header_hash)[::-1]
h = sha512(header_hash_bytes)
pow_hash = double_sha256(
ripemd160(h[:len(h) // 2]) + ripemd160(h[len(h) // 2:]))
return hexlify(pow_hash[::-1])
