Multisig with PST

/**
 * 2-of-3 multisig with a PST: fund a shared vault, then two co-signers sign independently.
 *
 *   ARREKTA_URL=http://127.0.0.1:28332 ARREKTA_ADMIN_TOKEN=... npx tsx examples/multisig-pst.ts
 */
import {
  addPstOrigins,
  addPstRedeem,
  combinePst,
  createClient,
  createMultisigPolicy,
  createPst,
  createTransaction,
  encodeAddress,
  equalLocks,
  finalizePst,
  fromHex,
  generateSeed,
  getChain,
  getCoins,
  isPstComplete,
  keychainFromSeed,
  mine,
  multisigLock,
  pstFromBase64,
  pstToBase64,
  sendPayment,
  sendTransaction,
  signPstWithSeed,
  txid,
} from 'arrekta-sdk';
 
const URL = process.env.ARREKTA_URL ?? 'http://127.0.0.1:28332';
const ADMIN = process.env.ARREKTA_ADMIN_TOKEN;
const SEED = fromHex(process.env.ARREKTA_SEED ?? 'a1'.repeat(32));
 
// 1. Connect; a funder and three co-signers.
const client = createClient({ url: URL, adminToken: ADMIN });
const { network } = await getChain(client);
const funder = keychainFromSeed(SEED, { network });
const seeds = [generateSeed(), generateSeed(), generateSeed()];
const cosigners = seeds.map((s) => keychainFromSeed(s, { network }));
if ((await getCoins(client, { wallet: funder })).length === 0) await mine(client, funder.address(0), 101);
 
// 2. The 2-of-3 policy and its address.
const policy = createMultisigPolicy(2, cosigners.map((kc) => kc.key(0)));
const vaultLock = multisigLock(policy);
const vault = encodeAddress(vaultLock, network);
console.log(`vault ${vault}`);
 
// 3. Fund the vault with 4 ARRK and confirm.
const fund = await sendPayment(client, { wallet: funder, to: vault, amount: '4' });
await mine(client, funder.address(0), 1);
const vout = fund.tx.outputs.findIndex((o) => equalLocks(o.lock, vaultLock));
const coin = fund.tx.outputs[vout]!;
 
// 4. The coordinator creates a PST paying 3.9998 ARRK back to the funder.
const tx = createTransaction({
  inputs: [{ prevout: { txid: txid(fund.tx), vout }, sequence: 0xffffffff }],
  outputs: [{ asset: coin.asset, amount: coin.amount - 20_000n, lock: funder.lock(1) }],
});
const unsigned = addPstOrigins(addPstRedeem(createPst(tx, [coin], network), [policy]), cosigners.map((kc) => kc.origin(0)));
const shared = pstToBase64(unsigned); // base64, sent to each co-signer
 
// 5. Co-signers 1 and 3 sign independently.
const signedA = pstToBase64(signPstWithSeed(pstFromBase64(shared), seeds[0]!));
const signedC = pstToBase64(signPstWithSeed(pstFromBase64(shared), seeds[2]!));
 
// 6. Combine, finalize and broadcast.
const combined = combinePst(pstFromBase64(signedA), pstFromBase64(signedC));
console.log('complete:', isPstComplete(combined));
const final = finalizePst(combined);
console.log('sent', (await sendTransaction(client, { tx: final })).txid);
await mine(client, funder.address(0), 1);

"""2-of-3 multisig with a PST: fund a shared vault, then two co-signers sign independently.
 
    ARREKTA_URL=http://127.0.0.1:28332 ARREKTA_ADMIN_TOKEN=... python examples/multisig_pst.py
"""
 
import os
 
from arrekta_sdk import (
    Client,
    Lock,
    OutPoint,
    Transaction,
    TxIn,
    TxOut,
    combine_pst,
    create_pst,
    encode_address,
    encode_pst,
    finalize_pst,
    generate_seed,
    keychain_from_seed,
    multisig_policy,
    pst_status,
    sign_pst,
)
 
URL = os.environ.get("ARREKTA_URL", "http://127.0.0.1:28332")
ADMIN = os.environ.get("ARREKTA_ADMIN_TOKEN")
SEED = bytes.fromhex(os.environ.get("ARREKTA_SEED", "a1" * 32))
 
 
def main() -> None:
    # 1. Connect; a funder and three co-signers.
    client = Client(URL, admin_token=ADMIN)
    network = client.get_chain()["network"]
    funder = keychain_from_seed(SEED, network=network)
    cosigners = [keychain_from_seed(generate_seed(), network=network) for _ in range(3)]
    if not client.get_coins(funder):
        client.mine(funder.address(0), 101)
 
    # 2. The 2-of-3 policy and its address.
    policy = multisig_policy(2, [kc.account_at(0) for kc in cosigners])
    policy_lock = Lock.to_multisig(policy)
    vault = encode_address(policy_lock, network)
    print(f"vault {vault}")
 
    # 3. Fund the vault with 4 ARRK and confirm.
    fund = client.send_payment(funder, vault, "4")
    client.mine(funder.address(0), 1)
    vout = next(i for i, o in enumerate(fund.tx.outputs) if o.lock == policy_lock)
    coin = fund.tx.outputs[vout]
 
    # 4. The coordinator creates a PST paying 3.9998 ARRK back to the funder.
    tx = Transaction(inputs=(TxIn(OutPoint(fund.tx.txid, vout)),),
                     outputs=(TxOut(coin.asset, coin.amount - 20_000, funder.lock(1)),))
    unsigned = create_pst(tx, [coin], network, redeem=[policy], origins=[kc.origin(0) for kc in cosigners])
    shared = encode_pst(unsigned)  # base64, sent to each co-signer
 
    # 5. Co-signers 1 and 3 sign independently.
    signed_a = encode_pst(sign_pst(shared, cosigners[0]))
    signed_c = encode_pst(sign_pst(shared, cosigners[2]))
 
    # 6. Combine, finalize and broadcast.
    combined = combine_pst(signed_a, signed_c)
    print("complete:", pst_status(combined)["complete"])
    final = finalize_pst(combined)
    print("sent", client.send_transaction(final)["txid"])
    client.mine(funder.address(0), 1)
 
 
if __name__ == "__main__":
    main()