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#!/usr/bin/env python3
# Copyright (c) 2015-2018 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
"""Utilities for manipulating blocks and transactions."""
from .address import (
key_to_p2sh_p2wpkh,
key_to_p2wpkh,
script_to_p2sh_p2wsh,
script_to_p2wsh,
)
from .messages import (
CBlock,
COIN,
COutPoint,
CTransaction,
CTxIn,
CTxInWitness,
CTxOut,
FromHex,
ToHex,
bytes_to_hex_str,
hash256,
hex_str_to_bytes,
ser_string,
ser_uint256,
sha256,
uint256_from_str,
)
from .script import (
CScript,
OP_0,
OP_1,
OP_CHECKMULTISIG,
OP_CHECKSIG,
OP_RETURN,
OP_TRUE,
hash160,
)
from .util import assert_equal
from io import BytesIO
# From BIP141
WITNESS_COMMITMENT_HEADER = b"\xaa\x21\xa9\xed"
def create_block(hashprev, coinbase, ntime=None):
"""Create a block (with regtest difficulty)."""
block = CBlock()
if ntime is None:
import time
block.nTime = int(time.time() + 600)
else:
block.nTime = ntime
block.hashPrevBlock = hashprev
block.nBits = 0x207fffff # difficulty retargeting is disabled in REGTEST chainparams
block.vtx.append(coinbase)
block.hashMerkleRoot = block.calc_merkle_root()
block.calc_sha256()
return block
def get_witness_script(witness_root, witness_nonce):
witness_commitment = uint256_from_str(hash256(ser_uint256(witness_root) + ser_uint256(witness_nonce)))
output_data = WITNESS_COMMITMENT_HEADER + ser_uint256(witness_commitment)
return CScript([OP_RETURN, output_data])
def add_witness_commitment(block, nonce=0):
"""Add a witness commitment to the block's coinbase transaction.
According to BIP141, blocks with witness rules active must commit to the
hash of all in-block transactions including witness."""
# First calculate the merkle root of the block's
# transactions, with witnesses.
witness_nonce = nonce
witness_root = block.calc_witness_merkle_root()
# witness_nonce should go to coinbase witness.
block.vtx[0].wit.vtxinwit = [CTxInWitness()]
block.vtx[0].wit.vtxinwit[0].scriptWitness.stack = [ser_uint256(witness_nonce)]
# witness commitment is the last OP_RETURN output in coinbase
block.vtx[0].vout.append(CTxOut(0, get_witness_script(witness_root, witness_nonce)))
block.vtx[0].rehash()
block.hashMerkleRoot = block.calc_merkle_root()
block.rehash()
def serialize_script_num(value):
r = bytearray(0)
if value == 0:
return r
neg = value < 0
absvalue = -value if neg else value
while (absvalue):
r.append(int(absvalue & 0xff))
absvalue >>= 8
if r[-1] & 0x80:
r.append(0x80 if neg else 0)
elif neg:
r[-1] |= 0x80
return r
def create_coinbase(height, pubkey=None):
"""Create a coinbase transaction, assuming no miner fees.
If pubkey is passed in, the coinbase output will be a P2PK output;
otherwise an anyone-can-spend output."""
coinbase = CTransaction()
coinbase.vin.append(CTxIn(COutPoint(0, 0xffffffff),
ser_string(serialize_script_num(height)), 0xffffffff))
coinbaseoutput = CTxOut()
coinbaseoutput.nValue = 50 * COIN
halvings = int(height / 150) # regtest
coinbaseoutput.nValue >>= halvings
if (pubkey is not None):
coinbaseoutput.scriptPubKey = CScript([pubkey, OP_CHECKSIG])
else:
coinbaseoutput.scriptPubKey = CScript([OP_TRUE])
coinbase.vout = [coinbaseoutput]
coinbase.calc_sha256()
return coinbase
def create_tx_with_script(prevtx, n, script_sig=b"", *, amount, script_pub_key=CScript()):
"""Return one-input, one-output transaction object
spending the prevtx's n-th output with the given amount.
Can optionally pass scriptPubKey and scriptSig, default is anyone-can-spend output.
"""
tx = CTransaction()
assert(n < len(prevtx.vout))
tx.vin.append(CTxIn(COutPoint(prevtx.sha256, n), script_sig, 0xffffffff))
tx.vout.append(CTxOut(amount, script_pub_key))
tx.calc_sha256()
return tx
def create_transaction(node, txid, to_address, *, amount):
""" Return signed transaction spending the first output of the
input txid. Note that the node must be able to sign for the
output that is being spent, and the node must not be running
multiple wallets.
"""
raw_tx = create_raw_transaction(node, txid, to_address, amount=amount)
tx = CTransaction()
tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx)))
return tx
def create_raw_transaction(node, txid, to_address, *, amount):
""" Return raw signed transaction spending the first output of the
input txid. Note that the node must be able to sign for the
output that is being spent, and the node must not be running
multiple wallets.
"""
rawtx = node.createrawtransaction(inputs=[{"txid": txid, "vout": 0}], outputs={to_address: amount})
signresult = node.signrawtransactionwithwallet(rawtx)
assert_equal(signresult["complete"], True)
return signresult['hex']
def get_legacy_sigopcount_block(block, accurate=True):
count = 0
for tx in block.vtx:
count += get_legacy_sigopcount_tx(tx, accurate)
return count
def get_legacy_sigopcount_tx(tx, accurate=True):
count = 0
for i in tx.vout:
count += i.scriptPubKey.GetSigOpCount(accurate)
for j in tx.vin:
# scriptSig might be of type bytes, so convert to CScript for the moment
count += CScript(j.scriptSig).GetSigOpCount(accurate)
return count
def witness_script(use_p2wsh, pubkey):
"""Create a scriptPubKey for a pay-to-witness TxOut.
This is either a P2WPKH output for the given pubkey, or a P2WSH output of a
1-of-1 multisig for the given pubkey. Returns the hex encoding of the
scriptPubKey."""
if not use_p2wsh:
# P2WPKH instead
pubkeyhash = hash160(hex_str_to_bytes(pubkey))
pkscript = CScript([OP_0, pubkeyhash])
else:
# 1-of-1 multisig
witness_program = CScript([OP_1, hex_str_to_bytes(pubkey), OP_1, OP_CHECKMULTISIG])
scripthash = sha256(witness_program)
pkscript = CScript([OP_0, scripthash])
return bytes_to_hex_str(pkscript)
def create_witness_tx(node, use_p2wsh, utxo, pubkey, encode_p2sh, amount):
"""Return a transaction (in hex) that spends the given utxo to a segwit output.
Optionally wrap the segwit output using P2SH."""
if use_p2wsh:
program = CScript([OP_1, hex_str_to_bytes(pubkey), OP_1, OP_CHECKMULTISIG])
addr = script_to_p2sh_p2wsh(program) if encode_p2sh else script_to_p2wsh(program)
else:
addr = key_to_p2sh_p2wpkh(pubkey) if encode_p2sh else key_to_p2wpkh(pubkey)
if not encode_p2sh:
assert_equal(node.getaddressinfo(addr)['scriptPubKey'], witness_script(use_p2wsh, pubkey))
return node.createrawtransaction([utxo], {addr: amount})
def send_to_witness(use_p2wsh, node, utxo, pubkey, encode_p2sh, amount, sign=True, insert_redeem_script=""):
"""Create a transaction spending a given utxo to a segwit output.
The output corresponds to the given pubkey: use_p2wsh determines whether to
use P2WPKH or P2WSH; encode_p2sh determines whether to wrap in P2SH.
sign=True will have the given node sign the transaction.
insert_redeem_script will be added to the scriptSig, if given."""
tx_to_witness = create_witness_tx(node, use_p2wsh, utxo, pubkey, encode_p2sh, amount)
if (sign):
signed = node.signrawtransactionwithwallet(tx_to_witness)
assert("errors" not in signed or len(["errors"]) == 0)
return node.sendrawtransaction(signed["hex"])
else:
if (insert_redeem_script):
tx = FromHex(CTransaction(), tx_to_witness)
tx.vin[0].scriptSig += CScript([hex_str_to_bytes(insert_redeem_script)])
tx_to_witness = ToHex(tx)
return node.sendrawtransaction(tx_to_witness)
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