#!/usr/bin/env python3 # Copyright (c) 2021 The Bitcoin Core developers # Distributed under the MIT software license, see the accompanying # file COPYING or http://www.opensource.org/licenses/mit-license.php. """Test a basic M-of-N multisig setup between multiple people using descriptor wallets and PSBTs, as well as a signing flow. This is meant to be documentation as much as functional tests, so it is kept as simple and readable as possible. """ from test_framework.address import base58_to_byte from test_framework.test_framework import BitcoinTestFramework from test_framework.util import ( assert_approx, assert_equal, ) class WalletMultisigDescriptorPSBTTest(BitcoinTestFramework): def set_test_params(self): self.num_nodes = 3 self.setup_clean_chain = True self.wallet_names = [] self.extra_args = [["-keypool=100"]] * self.num_nodes def skip_test_if_missing_module(self): self.skip_if_no_wallet() self.skip_if_no_sqlite() def _get_xpub(self, wallet): """Extract the wallet's xpubs using `listdescriptors` and pick the one from the `pkh` descriptor since it's least likely to be accidentally reused (legacy addresses).""" descriptor = next(filter(lambda d: d["desc"].startswith("pkh"), wallet.listdescriptors()["descriptors"])) return descriptor["desc"].split("]")[-1].split("/")[0] def _check_psbt(self, psbt, to, value, multisig): """Helper method for any of the N participants to check the psbt with decodepsbt and verify it is OK before signing.""" tx = multisig.decodepsbt(psbt)["tx"] amount = 0 for vout in tx["vout"]: address = vout["scriptPubKey"]["address"] assert_equal(multisig.getaddressinfo(address)["ischange"], address != to) if address == to: amount += vout["value"] assert_approx(amount, float(value), vspan=0.001) def generate_and_exchange_xpubs(self, participants): """Every participant generates an xpub. The most straightforward way is to create a new descriptor wallet. Avoid reusing this wallet for any other purpose..""" for i, node in enumerate(participants): node.createwallet(wallet_name=f"participant_{i}", descriptors=True) yield self._get_xpub(node.get_wallet_rpc(f"participant_{i}")) def participants_import_descriptors(self, participants, xpubs): """The multisig is created by importing the following descriptors. The resulting wallet is watch-only and every participant can do this.""" # some simple validation assert_equal(len(xpubs), self.N) # a sanity-check/assertion, this will throw if the base58 checksum of any of the provided xpubs are invalid for xpub in xpubs: base58_to_byte(xpub) for i, node in enumerate(participants): node.createwallet(wallet_name=f"{self.name}_{i}", blank=True, descriptors=True, disable_private_keys=True) multisig = node.get_wallet_rpc(f"{self.name}_{i}") external = multisig.getdescriptorinfo(f"wsh(sortedmulti({self.M},{f'/{0}/*,'.join(xpubs)}/{0}/*))") internal = multisig.getdescriptorinfo(f"wsh(sortedmulti({self.M},{f'/{1}/*,'.join(xpubs)}/{1}/*))") result = multisig.importdescriptors([ { # receiving addresses (internal: False) "desc": external["descriptor"], "active": True, "internal": False, "timestamp": "now", }, { # change addresses (internal: True) "desc": internal["descriptor"], "active": True, "internal": True, "timestamp": "now", }, ]) assert all(r["success"] for r in result) def get_multisig_receiving_address(self): """We will send funds to the resulting address (every participant should get the same addresses).""" multisig = self.nodes[0].get_wallet_rpc(f"{self.name}_{0}") receiving_address = multisig.getnewaddress() for i in range(1, self.N): assert_equal(receiving_address, self.nodes[i].get_wallet_rpc(f"{self.name}_{i}").getnewaddress()) return receiving_address def make_sending_transaction(self, to, value): """Make a sending transaction, created using walletcreatefundedpsbt (anyone can initiate this).""" return self.nodes[0].get_wallet_rpc(f"{self.name}_{0}").walletcreatefundedpsbt(inputs=[], outputs={to: value}, options={"feeRate": 0.00010}) def run_test(self): self.M = 2 self.N = self.num_nodes self.name = f"{self.M}_of_{self.N}_multisig" self.log.info(f"Testing {self.name}...") self.log.info("Generate and exchange xpubs...") xpubs = list(self.generate_and_exchange_xpubs(self.nodes)) self.log.info("Every participant imports the following descriptors to create the watch-only multisig...") self.participants_import_descriptors(self.nodes, xpubs) self.log.info("Get a mature utxo to send to the multisig...") coordinator_wallet = self.nodes[0].get_wallet_rpc(f"participant_{0}") coordinator_wallet.generatetoaddress(101, coordinator_wallet.getnewaddress()) deposit_amount = 6.15 multisig_receiving_address = self.get_multisig_receiving_address() self.log.info("Send funds to the resulting multisig receiving address...") coordinator_wallet.sendtoaddress(multisig_receiving_address, deposit_amount) self.nodes[0].generate(1) self.sync_all() for n in range(self.N): assert_approx(self.nodes[n].get_wallet_rpc(f"{self.name}_{n}").getbalance(), deposit_amount, vspan=0.001) self.log.info("Send a transaction from the multisig!") to = self.nodes[self.N - 1].get_wallet_rpc(f"participant_{self.N - 1}").getnewaddress() value = 1 psbt = self.make_sending_transaction(to, value) psbts = [] self.log.info("At least M users check the psbt with decodepsbt and (if OK) signs it with walletprocesspsbt...") for m in range(self.M): signers_multisig = self.nodes[m].get_wallet_rpc(f"{self.name}_{m}") self._check_psbt(psbt["psbt"], to, value, signers_multisig) signing_wallet = self.nodes[m].get_wallet_rpc(f"participant_{m}") partially_signed_psbt = signing_wallet.walletprocesspsbt(psbt["psbt"]) psbts.append(partially_signed_psbt["psbt"]) self.log.info("Collect the signed PSBTs with combinepsbt, finalizepsbt, then broadcast the resulting transaction...") combined = coordinator_wallet.combinepsbt(psbts) finalized = coordinator_wallet.finalizepsbt(combined) coordinator_wallet.sendrawtransaction(finalized["hex"]) self.log.info("Check that balances are correct after the transaction has been included in a block.") self.nodes[0].generate(1) self.sync_all() assert_approx(self.nodes[0].get_wallet_rpc(f"{self.name}_{0}").getbalance(), deposit_amount - value, vspan=0.001) assert_equal(self.nodes[self.N - 1].get_wallet_rpc(f"participant_{self.N - 1}").getbalance(), value) if __name__ == "__main__": WalletMultisigDescriptorPSBTTest().main()