forked from LBRYCommunity/lbry-sdk
99 lines
4 KiB
Python
99 lines
4 KiB
Python
|
import binascii
|
||
|
|
|
||
|
|
from lbryschema.hashing import sha256
|
||
|
|
|
||
|
|
|
||
|
|
class InvalidProofError(Exception): pass
|
||
|
|
|
||
|
|
|
||
|
|
def height_to_vch(n):
|
||
|
|
r = [0 for i in range(8)]
|
||
|
|
r[4] = n >> 24
|
||
|
|
r[5] = n >> 16
|
||
|
|
r[6] = n >> 8
|
||
|
|
r[7] = n % 256
|
||
|
|
# need to reset each value mod 256 because for values like 67784
|
||
|
|
# 67784 >> 8 = 264, which is obviously larger then the maximum
|
||
|
|
# value input into chr()
|
||
|
|
return ''.join([chr(x % 256) for x in r])
|
||
|
|
|
||
|
|
|
||
|
|
def get_hash_for_outpoint(txhash, nOut, nHeightOfLastTakeover):
|
||
|
|
txhash_hash = Hash(txhash)
|
||
|
|
nOut_hash = Hash(str(nOut))
|
||
|
|
height_of_last_takeover_hash = Hash(height_to_vch(nHeightOfLastTakeover))
|
||
|
|
outPointHash = Hash(txhash_hash + nOut_hash + height_of_last_takeover_hash)
|
||
|
|
return outPointHash
|
||
|
|
|
||
|
|
|
||
|
|
# noinspection PyPep8
|
||
|
|
def verify_proof(proof, rootHash, 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 = ''
|
||
|
|
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 += chr(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'], (long, int)):
|
||
|
|
raise InvalidProofError("nOut was invalid: {}".format(proof['nOut']))
|
||
|
|
if not isinstance(proof['last takeover height'], (long, 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 = Hash(to_hash)
|
||
|
|
|
||
|
|
if previous_computed_hash != binascii.unhexlify(rootHash)[::-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")
|
||
|
|
if 'txhash' in proof and 'nOut' in proof:
|
||
|
|
if name != reverse_computed_name[::-1]:
|
||
|
|
raise InvalidProofError("name did not match proof")
|
||
|
|
if not name.startswith(reverse_computed_name[::-1]):
|
||
|
|
raise InvalidProofError("name fragment does not match proof")
|
||
|
|
return True
|
||
|
|
|
||
|
|
def Hash(x):
|
||
|
|
if type(x) is unicode:
|
||
|
|
x = x.encode('utf-8')
|
||
|
|
return sha256(sha256(x))
|