def FromHex(obj, hex_string):
obj.deserialize(BytesIO(hex_str_to_bytes(hex_string)))
return obj
def create_tampered_rawtx_cbh(node_from, node_to, tx_amount, fee, mode):
genesis_block_hash = node_from.getblock(str(0))['hash']
# select necessary UTXOs
usp = node_from.listunspent()
assert (len(usp) != 0)
amount = Decimal('0')
inputs = []
for x in usp:
amount += Decimal(x['amount'])
inputs.append({"txid": x['txid'], "vout": x['vout']})
if amount >= tx_amount + fee:
break
outputs = {
node_from.getnewaddress(): (Decimal(amount) - tx_amount - fee),
node_to.getnewaddress(): tx_amount
}
rawTx = node_from.createrawtransaction(inputs, outputs)
# build an object from the raw Tx in order to be able to modify it
tx_01 = CTransaction()
f = StringIO(unhexlify(rawTx))
tx_01.deserialize(f)
# corrupt vouts in this Tx
for vout_idx in range(len(tx_01.vout)):
decodedScriptOrig = node_from.decodescript(
hexlify(tx_01.vout[vout_idx].scriptPubKey))
scriptOrigAsm = decodedScriptOrig['asm']
params = scriptOrigAsm.split()
hash160 = hex_str_to_bytes(params[2])
original_height = int(params[6])
original_hash = hex_str_to_bytes(params[5])
if mode == MODE_HEIGHT:
# new referenced block height
evil_height = -1
# new referenced block hash
modTargetHash = hex_str_to_bytes(swap_bytes(genesis_block_hash))
# build modified script: CScript is putting a 4f (OP_NEGATE) for our -1
# edit script.py to send different stuff for the -1 value (like ff itself!)
modScriptPubKey = CScript([
OP_DUP, OP_HASH160, hash160, OP_EQUALVERIFY, OP_CHECKSIG,
modTargetHash, evil_height, OP_CHECKBLOCKATHEIGHT
])
elif mode == MODE_SWAP_ARGS:
modScriptPubKey = CScript([
OP_DUP, OP_HASH160, hash160, OP_EQUALVERIFY, OP_CHECKSIG,
original_height, original_hash, OP_CHECKBLOCKATHEIGHT
])
elif mode == MODE_NON_MIN_ENC:
non_min_h = hex_str_to_bytes("07000000")
modScriptPubKey = CScript([
OP_DUP, OP_HASH160, hash160, OP_EQUALVERIFY, OP_CHECKSIG,
original_hash, non_min_h, OP_CHECKBLOCKATHEIGHT
])
else:
assert (False)
tx_01.vout[vout_idx].scriptPubKey = modScriptPubKey
tx_01.rehash()
signedRawTx = node_from.signrawtransaction(ToHex(tx_01))
return signedRawTx