cltv.spec.ts

import * as assert from 'assert';
import ECPairFactory from 'ecpair';
import * as ecc from 'tiny-secp256k1';
import { before, describe, it } from 'mocha';
import * as bitcoin from 'bitcoinjs-lib';
import { regtestUtils } from './_regtest.js';
import { reverseBuffer } from 'bitcoinjs-lib/src/bufferutils';
import * as tools from 'uint8array-tools';

const ECPair = ECPairFactory(ecc);
const regtest = regtestUtils.network;
import bip65 from 'bip65';

function toOutputScript(address: string): Uint8Array {
  return bitcoin.address.toOutputScript(address, regtest);
}

function idToHash(txid: string): Uint8Array {
  return reverseBuffer(tools.fromHex(txid));
}

const alice = ECPair.fromWIF(
  'cScfkGjbzzoeewVWmU2hYPUHeVGJRDdFt7WhmrVVGkxpmPP8BHWe',
  regtest,
);
const bob = ECPair.fromWIF(
  'cMkopUXKWsEzAjfa1zApksGRwjVpJRB3831qM9W4gKZsLwjHXA9x',
  regtest,
);

describe('bitcoinjs-lib (transactions w/ CLTV)', () => {
  // force update MTP
  before(async () => {
    await regtestUtils.mine(11);
  });

  const hashType = bitcoin.Transaction.SIGHASH_ALL;

  interface KeyPair {
    publicKey: Uint8Array;
  }
  function cltvCheckSigOutput(
    aQ: KeyPair,
    bQ: KeyPair,
    lockTime: number,
  ): Uint8Array {
    return bitcoin.script.fromASM(
      `
      OP_IF
          ${tools.toHex(bitcoin.script.number.encode(lockTime))}
          OP_CHECKLOCKTIMEVERIFY
          OP_DROP
      OP_ELSE
          ${tools.toHex(bQ.publicKey)}
          OP_CHECKSIGVERIFY
      OP_ENDIF
      ${tools.toHex(aQ.publicKey)}
      OP_CHECKSIG
    `
        .trim()
        .replace(/\s+/g, ' '),
    );
  }

  function utcNow(): number {
    return Math.floor(Date.now() / 1000);
  }

  // expiry past, {Alice's signature} OP_TRUE
  it(
    'can create (and broadcast via 3PBP) a Transaction where Alice can redeem ' +
      'the output after the expiry (in the past)',
    async () => {
      // 3 hours ago
      const lockTime = bip65.encode({ utc: utcNow() - 3600 * 3 });
      const redeemScript = cltvCheckSigOutput(alice, bob, lockTime);
      const { address } = bitcoin.payments.p2sh({
        redeem: { output: redeemScript, network: regtest },
        network: regtest,
      });

      // fund the P2SH(CLTV) address
      const unspent = await regtestUtils.faucet(address!, 1e5);
      const tx = new bitcoin.Transaction();
      tx.locktime = lockTime;
      // Note: nSequence MUST be <= 0xfffffffe otherwise OP_CHECKLOCKTIMEVERIFY will fail.
      tx.addInput(idToHash(unspent.txId), unspent.vout, 0xfffffffe);
      tx.addOutput(toOutputScript(regtestUtils.RANDOM_ADDRESS), BigInt(7e4));

      // {Alice's signature} OP_TRUE
      const signatureHash = tx.hashForSignature(0, redeemScript, hashType);
      const redeemScriptSig = bitcoin.payments.p2sh({
        redeem: {
          input: bitcoin.script.compile([
            bitcoin.script.signature.encode(
              alice.sign(signatureHash),
              hashType,
            ),
            bitcoin.opcodes.OP_TRUE,
          ]),
          output: redeemScript,
        },
      }).input;
      tx.setInputScript(0, redeemScriptSig!);

      await regtestUtils.broadcast(tx.toHex());

      await regtestUtils.verify({
        txId: tx.getId(),
        address: regtestUtils.RANDOM_ADDRESS,
        vout: 0,
        value: 7e4,
      });
    },
  );

  // expiry will pass, {Alice's signature} OP_TRUE
  it(
    'can create (and broadcast via 3PBP) a Transaction where Alice can redeem ' +
      'the output after the expiry (in the future)',
    async () => {
      const height = await regtestUtils.height();
      // 5 blocks from now
      const lockTime = bip65.encode({ blocks: height + 5 });
      const redeemScript = cltvCheckSigOutput(alice, bob, lockTime);
      const { address } = bitcoin.payments.p2sh({
        redeem: { output: redeemScript, network: regtest },
        network: regtest,
      });

      // fund the P2SH(CLTV) address
      const unspent = await regtestUtils.faucet(address!, 1e5);
      const tx = new bitcoin.Transaction();
      tx.locktime = lockTime;
      // Note: nSequence MUST be <= 0xfffffffe otherwise OP_CHECKLOCKTIMEVERIFY will fail.
      tx.addInput(idToHash(unspent.txId), unspent.vout, 0xfffffffe);
      tx.addOutput(toOutputScript(regtestUtils.RANDOM_ADDRESS), BigInt(7e4));

      // {Alice's signature} OP_TRUE
      const signatureHash = tx.hashForSignature(0, redeemScript, hashType);
      const redeemScriptSig = bitcoin.payments.p2sh({
        redeem: {
          input: bitcoin.script.compile([
            bitcoin.script.signature.encode(
              alice.sign(signatureHash),
              hashType,
            ),
            bitcoin.opcodes.OP_TRUE,
          ]),
          output: redeemScript,
        },
      }).input;
      tx.setInputScript(0, redeemScriptSig!);

      // TODO: test that it failures _prior_ to expiry, unfortunately, race conditions when run concurrently
      // ...
      // into the future!
      await regtestUtils.mine(5);
      await regtestUtils.broadcast(tx.toHex());
      await regtestUtils.verify({
        txId: tx.getId(),
        address: regtestUtils.RANDOM_ADDRESS,
        vout: 0,
        value: 7e4,
      });
    },
  );

  // expiry ignored, {Bob's signature} {Alice's signature} OP_FALSE
  it(
    'can create (and broadcast via 3PBP) a Transaction where Alice and Bob can ' +
      'redeem the output at any time',
    async () => {
      // two hours ago
      const lockTime = bip65.encode({ utc: utcNow() - 3600 * 2 });
      const redeemScript = cltvCheckSigOutput(alice, bob, lockTime);
      const { address } = bitcoin.payments.p2sh({
        redeem: { output: redeemScript, network: regtest },
        network: regtest,
      });

      // fund the P2SH(CLTV) address
      const unspent = await regtestUtils.faucet(address!, 2e5);
      const tx = new bitcoin.Transaction();
      tx.locktime = lockTime;
      // Note: nSequence MUST be <= 0xfffffffe otherwise OP_CHECKLOCKTIMEVERIFY will fail.
      tx.addInput(idToHash(unspent.txId), unspent.vout, 0xfffffffe);
      tx.addOutput(toOutputScript(regtestUtils.RANDOM_ADDRESS), BigInt(8e4));

      // {Alice's signature} {Bob's signature} OP_FALSE
      const signatureHash = tx.hashForSignature(0, redeemScript, hashType);
      const redeemScriptSig = bitcoin.payments.p2sh({
        redeem: {
          input: bitcoin.script.compile([
            bitcoin.script.signature.encode(
              alice.sign(signatureHash),
              hashType,
            ),
            bitcoin.script.signature.encode(bob.sign(signatureHash), hashType),
            bitcoin.opcodes.OP_FALSE,
          ]),
          output: redeemScript,
        },
      }).input;
      tx.setInputScript(0, redeemScriptSig!);

      await regtestUtils.broadcast(tx.toHex());
      await regtestUtils.verify({
        txId: tx.getId(),
        address: regtestUtils.RANDOM_ADDRESS,
        vout: 0,
        value: 8e4,
      });
    },
  );

  // expiry in the future, {Alice's signature} OP_TRUE
  it(
    'can create (but fail to broadcast via 3PBP) a Transaction where Alice ' +
      'attempts to redeem before the expiry',
    async () => {
      // two hours from now
      const lockTime = bip65.encode({ utc: utcNow() + 3600 * 2 });
      const redeemScript = cltvCheckSigOutput(alice, bob, lockTime);
      const { address } = bitcoin.payments.p2sh({
        redeem: { output: redeemScript, network: regtest },
        network: regtest,
      });

      // fund the P2SH(CLTV) address
      const unspent = await regtestUtils.faucet(address!, 2e4);
      const tx = new bitcoin.Transaction();
      tx.locktime = lockTime;
      // Note: nSequence MUST be <= 0xfffffffe otherwise OP_CHECKLOCKTIMEVERIFY will fail.
      tx.addInput(idToHash(unspent.txId), unspent.vout, 0xfffffffe);
      tx.addOutput(toOutputScript(regtestUtils.RANDOM_ADDRESS), BigInt(1e4));

      // {Alice's signature} OP_TRUE
      const signatureHash = tx.hashForSignature(0, redeemScript, hashType);
      const redeemScriptSig = bitcoin.payments.p2sh({
        redeem: {
          input: bitcoin.script.compile([
            bitcoin.script.signature.encode(
              alice.sign(signatureHash),
              hashType,
            ),
            bitcoin.script.signature.encode(bob.sign(signatureHash), hashType),
            bitcoin.opcodes.OP_TRUE,
          ]),
          output: redeemScript,
        },
      }).input;
      tx.setInputScript(0, redeemScriptSig!);

      await regtestUtils.broadcast(tx.toHex()).catch(err => {
        assert.throws(() => {
          if (err) throw err;
        }, /Error: non-final/);
      });
    },
  );
});