#!/usr/bin/env python3 # Copyright (c) 2015-2017 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)