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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 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_transaction(prevtx, n, sig, value, script_pub_key=CScript()):
"""Create a transaction.
If the script_pub_key is not specified, make it anyone-can-spend."""
tx = CTransaction()
assert(n < len(prevtx.vout))
tx.vin.append(CTxIn(COutPoint(prevtx.sha256, n), sig, 0xffffffff))
tx.vout.append(CTxOut(value, script_pub_key))
tx.calc_sha256()
return tx
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-wtiness 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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