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| 1 | +#!/usr/bin/env python3 |
| 2 | +# Copyright (c) 2024 The Bitcoin Core developers |
| 3 | +# Distributed under the MIT software license, see the accompanying |
| 4 | +# file COPYING or http://www.opensource.org/licenses/mit-license.php. |
| 5 | +"""Test a miniscript multisig that starts as 4-of-4 and "decays" to 3-of-4, 2-of-4, and finally 1-of-4 at each future halvening block height. |
| 6 | +
|
| 7 | +Spending policy: `thresh(4,pk(key_1),pk(key_2),pk(key_3),pk(key_4),after(t1),after(t2),after(t3))` |
| 8 | +This is similar to `test/functional/wallet_multisig_descriptor_psbt.py`. |
| 9 | +""" |
| 10 | + |
| 11 | +import random |
| 12 | +from test_framework.test_framework import BitcoinTestFramework |
| 13 | +from test_framework.util import ( |
| 14 | + assert_approx, |
| 15 | + assert_equal, |
| 16 | + assert_raises_rpc_error, |
| 17 | +) |
| 18 | + |
| 19 | + |
| 20 | +class WalletMiniscriptDecayingMultisigDescriptorPSBTTest(BitcoinTestFramework): |
| 21 | + def add_options(self, parser): |
| 22 | + self.add_wallet_options(parser, legacy=False) |
| 23 | + |
| 24 | + def set_test_params(self): |
| 25 | + self.num_nodes = 1 |
| 26 | + self.setup_clean_chain = True |
| 27 | + self.wallet_names = [] |
| 28 | + self.extra_args = [["-keypool=100"]] |
| 29 | + |
| 30 | + def skip_test_if_missing_module(self): |
| 31 | + self.skip_if_no_wallet() |
| 32 | + self.skip_if_no_sqlite() |
| 33 | + |
| 34 | + @staticmethod |
| 35 | + def _get_xpub(wallet, internal): |
| 36 | + """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).""" |
| 37 | + pkh_descriptor = next(filter(lambda d: d["desc"].startswith("pkh(") and d["internal"] == internal, wallet.listdescriptors()["descriptors"])) |
| 38 | + # keep all key origin information (master key fingerprint and all derivation steps) for proper support of hardware devices |
| 39 | + # see section 'Key origin identification' in 'doc/descriptors.md' for more details... |
| 40 | + return pkh_descriptor["desc"].split("pkh(")[1].split(")")[0] |
| 41 | + |
| 42 | + def create_multisig(self, external_xpubs, internal_xpubs): |
| 43 | + """The multisig is created by importing the following descriptors. The resulting wallet is watch-only and every signer can do this.""" |
| 44 | + self.node.createwallet(wallet_name=f"{self.name}", blank=True, descriptors=True, disable_private_keys=True) |
| 45 | + multisig = self.node.get_wallet_rpc(f"{self.name}") |
| 46 | + # spending policy: `thresh(4,pk(key_1),pk(key_2),pk(key_3),pk(key_4),after(t1),after(t2),after(t3))` |
| 47 | + # IMPORTANT: when backing up your descriptor, the order of key_1...key_4 must be correct! |
| 48 | + external = multisig.getdescriptorinfo(f"wsh(thresh({self.N},pk({'),s:pk('.join(external_xpubs)}),sln:after({'),sln:after('.join(map(str, self.locktimes))})))") |
| 49 | + internal = multisig.getdescriptorinfo(f"wsh(thresh({self.N},pk({'),s:pk('.join(internal_xpubs)}),sln:after({'),sln:after('.join(map(str, self.locktimes))})))") |
| 50 | + result = multisig.importdescriptors([ |
| 51 | + { # receiving addresses (internal: False) |
| 52 | + "desc": external["descriptor"], |
| 53 | + "active": True, |
| 54 | + "internal": False, |
| 55 | + "timestamp": "now", |
| 56 | + }, |
| 57 | + { # change addresses (internal: True) |
| 58 | + "desc": internal["descriptor"], |
| 59 | + "active": True, |
| 60 | + "internal": True, |
| 61 | + "timestamp": "now", |
| 62 | + }, |
| 63 | + ]) |
| 64 | + assert all(r["success"] for r in result) |
| 65 | + return multisig |
| 66 | + |
| 67 | + def run_test(self): |
| 68 | + self.node = self.nodes[0] |
| 69 | + self.M = 4 # starts as 4-of-4 |
| 70 | + self.N = 4 |
| 71 | + |
| 72 | + self.locktimes = [104, 106, 108] |
| 73 | + assert_equal(len(self.locktimes), self.N - 1) |
| 74 | + |
| 75 | + self.name = f"{self.M}_of_{self.N}_decaying_multisig" |
| 76 | + self.log.info(f"Testing a miniscript multisig which starts as 4-of-4 and 'decays' to 3-of-4 at block height {self.locktimes[0]}, 2-of-4 at {self.locktimes[1]}, and finally 1-of-4 at {self.locktimes[2]}...") |
| 77 | + |
| 78 | + self.log.info("Create the signer wallets and get their xpubs...") |
| 79 | + signers = [self.node.get_wallet_rpc(self.node.createwallet(wallet_name=f"signer_{i}", descriptors=True)["name"]) for i in range(self.N)] |
| 80 | + external_xpubs, internal_xpubs = [[self._get_xpub(signer, internal) for signer in signers] for internal in [False, True]] |
| 81 | + |
| 82 | + self.log.info("Create the watch-only decaying multisig using signers' xpubs...") |
| 83 | + multisig = self.create_multisig(external_xpubs, internal_xpubs) |
| 84 | + |
| 85 | + self.log.info("Get a mature utxo to send to the multisig...") |
| 86 | + coordinator_wallet = self.node.get_wallet_rpc(self.node.createwallet(wallet_name="coordinator", descriptors=True)["name"]) |
| 87 | + self.generatetoaddress(self.node, 101, coordinator_wallet.getnewaddress()) |
| 88 | + |
| 89 | + self.log.info("Send funds to the multisig's receiving address...") |
| 90 | + deposit_amount = 6.15 |
| 91 | + coordinator_wallet.sendtoaddress(multisig.getnewaddress(), deposit_amount) |
| 92 | + self.generate(self.node, 1) |
| 93 | + assert_approx(multisig.getbalance(), deposit_amount, vspan=0.001) |
| 94 | + |
| 95 | + self.log.info("Send transactions from the multisig as required signers decay...") |
| 96 | + amount = 1.5 |
| 97 | + receiver = signers[0] |
| 98 | + sent = 0 |
| 99 | + for locktime in [0] + self.locktimes: |
| 100 | + self.log.info(f"At block height >= {locktime} this multisig is {self.M}-of-{self.N}") |
| 101 | + current_height = self.node.getblock(self.node.getbestblockhash())['height'] |
| 102 | + |
| 103 | + # in this test each signer signs the same psbt "in series" one after the other. |
| 104 | + # Another option is for each signer to sign the original psbt, and then combine |
| 105 | + # and finalize these. In some cases this may be more optimal for coordination. |
| 106 | + psbt = multisig.walletcreatefundedpsbt(inputs=[], outputs={receiver.getnewaddress(): amount}, feeRate=0.00010, locktime=locktime) |
| 107 | + # the random sample asserts that any of the signing keys can sign for the 3-of-4, |
| 108 | + # 2-of-4, and 1-of-4. While this is basic behavior of the miniscript thresh primitive, |
| 109 | + # it is a critical property of this wallet. |
| 110 | + for i, m in enumerate(random.sample(range(self.M), self.M)): |
| 111 | + psbt = signers[m].walletprocesspsbt(psbt["psbt"]) |
| 112 | + assert_equal(psbt["complete"], i == self.M - 1) |
| 113 | + |
| 114 | + if self.M < self.N: |
| 115 | + self.log.info(f"Check that the time-locked transaction is too immature to spend with {self.M}-of-{self.N} at block height {current_height}...") |
| 116 | + assert_equal(current_height >= locktime, False) |
| 117 | + assert_raises_rpc_error(-26, "non-final", multisig.sendrawtransaction, psbt["hex"]) |
| 118 | + |
| 119 | + self.log.info(f"Generate blocks to reach the time-lock block height {locktime} and broadcast the transaction...") |
| 120 | + self.generate(self.node, locktime - current_height) |
| 121 | + else: |
| 122 | + self.log.info("All the signers are required to spend before the first locktime") |
| 123 | + |
| 124 | + multisig.sendrawtransaction(psbt["hex"]) |
| 125 | + sent += amount |
| 126 | + |
| 127 | + self.log.info("Check that balances are correct after the transaction has been included in a block...") |
| 128 | + self.generate(self.node, 1) |
| 129 | + assert_approx(multisig.getbalance(), deposit_amount - sent, vspan=0.001) |
| 130 | + assert_equal(receiver.getbalance(), sent) |
| 131 | + |
| 132 | + self.M -= 1 # decay the number of required signers for the next locktime.. |
| 133 | + |
| 134 | + |
| 135 | +if __name__ == "__main__": |
| 136 | + WalletMiniscriptDecayingMultisigDescriptorPSBTTest(__file__).main() |
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