(not an issue) Electrum seed format example

Edit 2 (from junderw): I made an Electrum seed library: Here is the github and it can be installed with npm install electrum-mnemonic

Edit (from junderw): See my reply below for an example of segwit wallet as well

After wasting half a day and reading Electrum docs & sources, here’s an example how to work with electrum seed format:

const crypto = require('crypto');
const bitcoin = require('bitcoinjs-lib');

function  mnemonic2seed(mnemonic, passphrase = '', iterations = 2048) {
    return crypto.pbkdf2Sync(mnemonic, 'electrum' + passphrase, iterations, 64, 'sha512');
}

const root = bitcoin.bip32.fromSeed(mnemonic2seed("<SEED HERE>"));
let xpub = root.toBase58();

const index = 1;
const node = bitcoin.bip32.fromBase58(xpub);
const externalAddress = bitcoin.payments.p2pkh({
  pubkey: node.derive(0).derive(index).publicKey,
}).address;

[junderw]

This is a bit more complete and covers both legacy and segwit.

const crypto = require('crypto');
const bitcoin = require('bitcoinjs-lib');
const bs58 = require('bs58check');
const assert = require('assert');

function mnemonic2seed(mnemonic, passphrase = '', iterations = 2048) {
  return crypto.pbkdf2Sync(
    mnemonic,
    'electrum' + passphrase,
    iterations,
    64,
    'sha512',
  );
}

function toXpub(yOrZPub) {
  return bs58.encode(
    Buffer.concat([
      Buffer.from('0488B21E', 'hex'),
      bs58.decode(yOrZPub).slice(4),
    ]),
  );
}

function checkBackup(backup, type = 'segwit') {
  const versions = {
    segwit: '100',
    standard: '01',
  }
  const hmac = crypto.createHmac('SHA512', 'Seed version')
  hmac.update(backup)
  const hx = hmac.digest('hex')
  if (!hx.startsWith(versions[type])) throw new Error('Invalid Backup Seed')

  return backup
}

function electrumWalletTests(
  backup,
  expectedAddress,
  expectedXpub,
  paymentFunc, // turn pubkey into payment object
  xpubDeriveFunc, // turn the root of bip32 master node into master pub node
) {
  const seed = mnemonic2seed(backup);
  const root = bitcoin.bip32.fromSeed(seed);
  const xpub = xpubDeriveFunc(root).neutered().toBase58();

  assert.strictEqual(xpub, expectedXpub);

  const index = 0;
  const node = bitcoin.bip32.fromBase58(xpub);
  const externalAddress = paymentFunc(node.derivePath(`0/${index}`).publicKey)
    .address;

  assert.strictEqual(externalAddress, expectedAddress);
}

// segwit wallet
electrumWalletTests(
  checkBackup('bullet wife mass allow quick degree rhythm fetch divert hotel vintage cruel', 'segwit'),
  'bc1qc8t8tadxwnw5fqfqycxl9ljahgp8g6yl9zzuwy',
  toXpub(
    'zpub6mux8KS53pqPCudXHvZYfj9UGmgWPMsJj9vczmosXE5dR3QubjQNw4ZqDovPa3af4hxFoVPvY8Q8VGQsriZRAjsRiDNLmaj3Yx9iKcjaBVV',
  ),
  function (pubkey) {
    return bitcoin.payments.p2wpkh({
      pubkey,
    });
  },
  function (root) {
    return root.derivePath("m/0'");
  },
);

// legacy wallet
electrumWalletTests(
  checkBackup('decade width renew post mistake orange record drink vintage sorry chalk hard', 'standard'),
  '1U9sVduetA4qE388QASN2sqpcee3PJbmx',
  'xpub661MyMwAqRbcFm9rdav51WyLWC3oEHU91XUWAv8Y8AkPg5hXDu2ta1B9C3u1aWDVFo5qmJD8bJTUUJD6dUJ9AeW1NM5rGNyysXx41u5gmmH',
  function (pubkey) {
    return bitcoin.payments.p2pkh({
      pubkey,
    });
  },
  function (root) {
    return root;
  },
);

[junderw]

@Overtorment I made a library that normalizes as close to Python3 as possible.

I tried a few Japanese seeds and it works with Electrum… but it’s kinda scary to include non-english wordlists rn.

https://github.com/bitcoinjs/electrum-mnemonic