#!/usr/bin/env python3

#

# Copyright (C) 2018 The python-bitcointx developers

# Copyright (C) 2019 The python-elementstx developers

#

# This file is part of python-elementstx.

#

# It is subject to the license terms in the LICENSE file found in the top-level

# directory of this distribution.

#

# No part of python-elementstx, including this file, may be copied, modified,

# propagated, or distributed except according to the terms contained in the

# LICENSE file.

# This code loads raw transaction an the blinding key from two separate files,

# and then tries to unblind vouts of the transaction with this blinding keys.

# normally, only one vout would be unblinded.

# pylama:ignore=E501

import sys

from bitcointx import select_chain_params, get_current_chain_params

from bitcointx.core import x, satoshi_to_coins

from bitcointx.wallet import CCoinKey, CCoinAddress

from elementstx import ElementsParams

from elementstx.core import CElementsTransaction, UnblindingSuccess

from elementstx.wallet import CCoinConfidentialAddress

if __name__ == '__main__':

if len(sys.argv) not in (3, 4):

print("usage: {} <raw-hex-tx-file> <blinding-key-file> [chainparams]"

.format(sys.argv[0]))

sys.exit(-1)

if len(sys.argv) == 4:

select_chain_params(sys.argv[3])

if not isinstance(get_current_chain_params(), ElementsParams):

print('specified chainparams is not Elements-compatible')

sys.exit(-1)

else:

# Switch the chain parameters to Elements regtest

select_chain_params('elements')

# Read in and decode the blinded transaction.

# expected to be hex-encoded as one line.

with open(sys.argv[1]) as f:

# We could use CTransaction here, but if we want to

# use mypy to do static checking, we need to use the elements-specific

# classes. mypy does cannot know about dynamic class dispatch.

tx = CElementsTransaction.deserialize(x(f.readline().rstrip()))

# Read in the blinding key, expected to be in WIF format.

with open(sys.argv[2]) as f:

bkey = CCoinKey.from_secret_bytes(x(f.readline().rstrip()))

# Iterate through transaction ouptputs, and unblind what we can.

print("")

for n, vout in enumerate(tx.vout):

# Note that nValue of vout in Elements is not a simple int,

# but CConfidentialValue, which can either be explicit, and can be

# converted to satoshis with to_amount(), or it can be blinded, in

# which case you need to unblind the output to know its value.

if vout.nValue.is_explicit():

# The output is not blinded, we can access the values right away

assert vout.nAsset.is_explicit(), "unblinding just the asset is not supported"

if vout.is_fee():

print("vout {}: fee".format(n))

else:

print("vout {}: explicit".format(n))

print(" destination address:",

CCoinAddress.from_scriptPubKey(tx.vout[n].scriptPubKey))

print(" amount:\t\t", satoshi_to_coins(vout.nValue.to_amount()))

print(" asset:\t\t", vout.nAsset.to_asset())

else:

# Try to unblind the output with the given blinding key

result = vout.unblind_confidential_pair(

bkey, tx.wit.vtxoutwit[n].rangeproof)

if result.error:

# Nope, our blinding key is not good for this output

print("vout {}: cannot unblind: {}".format(n, result.error))

print(" destination address:",

CCoinAddress.from_scriptPubKey(tx.vout[n].scriptPubKey))

if not tx.wit.is_null():

rpinfo = tx.wit.vtxoutwit[n].get_rangeproof_info()

if rpinfo:

print(' ct-exponent', rpinfo.exp)

print(' ct-bits', rpinfo.mantissa)

print(' value-minimum',

satoshi_to_coins(rpinfo.value_min, check_range=False))

print(' value-maximum',

satoshi_to_coins(rpinfo.value_max, check_range=False))

else:

assert isinstance(result, UnblindingSuccess)

# Successfully unblinded the output !

print("vout {}: unblinded".format(n))

addr = CCoinAddress.from_scriptPubKey(tx.vout[n].scriptPubKey)

conf_addr = CCoinConfidentialAddress.from_unconfidential(addr, bkey.pub)

print(" destination address:")

print(" confidential:\t", conf_addr)

print(" unconfidential:\t", addr)

print(" amount:\t\t", satoshi_to_coins(result.amount))

print(" blinding_factor:\t", result.blinding_factor)

print(" asset:\t\t", result.asset)

print(" asset_blinding_factor:", result.asset_blinding_factor)

print("")