@trezor/utxo-lib/lib/payments/p2tr.js

Client-side Bitcoin-like JavaScript library

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.p2tr = p2tr;
const tslib_1 = require("tslib");
const bech32_1 = require("bech32");
const tiny_secp256k1_1 = tslib_1.__importDefault(require("tiny-secp256k1"));
const bcrypto = tslib_1.__importStar(require("../crypto"));
const networks_1 = require("../networks");
const bscript = tslib_1.__importStar(require("../script"));
const lazy = tslib_1.__importStar(require("./lazy"));
const types_1 = require("../types");
const {
  OPS
} = bscript;
const TAGS = ['TapLeaf', 'TapBranch', 'TapTweak', 'KeyAgg list', 'KeyAgg coefficient'];
const TAGGED_HASH_PREFIXES = TAGS.reduce((obj, tag) => {
  const tagHash = bcrypto.sha256(Buffer.from(tag));
  obj[tag] = Buffer.concat([tagHash, tagHash]);
  return obj;
}, {});
const EVEN_Y_COORD_PREFIX = new Uint8Array([0x02]);
function taggedHash(prefix, data) {
  return bcrypto.sha256(Buffer.concat([TAGGED_HASH_PREFIXES[prefix], data]));
}
function tapTweakPubkey(pubkey, tapTreeRoot) {
  let tapTweak;
  if (tapTreeRoot) {
    tapTweak = taggedHash('TapTweak', Buffer.concat([pubkey, tapTreeRoot]));
  } else {
    tapTweak = taggedHash('TapTweak', pubkey);
  }
  const tweakedPubkey = tiny_secp256k1_1.default.pointAddScalar(Buffer.concat([EVEN_Y_COORD_PREFIX, pubkey]), tapTweak);
  return {
    parity: tweakedPubkey[0] === EVEN_Y_COORD_PREFIX[0] ? 0 : 1,
    pubkey: tweakedPubkey.slice(1)
  };
}
const liftX = pubkey => {
  const offset = pubkey.length === 33 ? 1 : 0;
  return pubkey.subarray(offset);
};
function p2tr(a, opts) {
  if (!a.address && !a.pubkey && !a.output) throw new TypeError('Not enough data');
  opts = Object.assign({
    validate: true
  }, opts || {});
  const network = a.network || networks_1.bitcoin;
  const o = {
    name: 'p2tr',
    network
  };
  (0, types_1.typeforce)({
    network: types_1.typeforce.maybe(types_1.typeforce.Object),
    address: types_1.typeforce.maybe(types_1.typeforce.String),
    output: types_1.typeforce.maybe(types_1.typeforce.BufferN(34)),
    pubkey: types_1.typeforce.maybe(types_1.typeforce.anyOf(types_1.typeforce.BufferN(32), types_1.typeforce.BufferN(33)))
  }, a);
  const _address = lazy.value(() => {
    const result = bech32_1.bech32m.decode(a.address);
    const version = result.words.shift();
    const data = bech32_1.bech32m.fromWords(result.words);
    return {
      version,
      prefix: result.prefix,
      data: Buffer.from(data)
    };
  });
  lazy.prop(o, 'address', () => {
    if (!o.hash) return;
    const words = bech32_1.bech32m.toWords(o.hash);
    words.unshift(0x01);
    return bech32_1.bech32m.encode(network.bech32, words);
  });
  lazy.prop(o, 'hash', () => {
    if (a.output) return a.output.subarray(2);
    if (a.address) return _address().data;
    if (a.pubkey) {
      return tapTweakPubkey(liftX(a.pubkey)).pubkey;
    }
  });
  lazy.prop(o, 'output', () => {
    if (!o.hash) return;
    return bscript.compile([OPS.OP_1, o.hash]);
  });
  if (opts.validate) {
    let hash = Buffer.from([]);
    if (a.address) {
      const {
        prefix,
        version,
        data
      } = _address();
      if (prefix !== network.bech32) throw new TypeError('Invalid prefix or Network mismatch');
      if (version !== 0x01) throw new TypeError('Invalid address version');
      if (data.length !== 32) throw new TypeError('Invalid address data');
      hash = data;
    }
    if (a.hash) {
      if (hash.length > 0 && !hash.equals(a.hash)) throw new TypeError('Hash mismatch');else hash = a.hash;
    }
    if (a.output) {
      if (a.output[0] !== OPS.OP_1 || a.output[1] !== 0x20) throw new TypeError('p2tr output is invalid');
      const hash2 = a.output.subarray(2);
      if (hash.length > 0 && !hash.equals(hash2)) throw new TypeError('Hash mismatch');else hash = hash2;
    }
    if (a.pubkey) {
      const pkh = tapTweakPubkey(liftX(a.pubkey)).pubkey;
      if (hash.length > 0 && !hash.equals(pkh)) throw new TypeError('Hash mismatch');else hash = pkh;
      if (!tiny_secp256k1_1.default.isPoint(Buffer.concat([EVEN_Y_COORD_PREFIX, liftX(a.pubkey)]))) throw new TypeError('Invalid pubkey for p2tr');
    }
  }
  return Object.assign(o, a);
}
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