Telegram website login widget, signature check sample using Node.js

check_telegram_signature.js

// Copied by https://gist.github.com/dotcypress/8fd12d6e886cd74bba8f1aa8dbd346aa,
// thanks for improving code style

const { createHash, createHmac } = require('crypto');
const TOKEN = "ABC:12345...";

// I prefer get the secret's hash once but check the gist linked
// on line 1 if you prefer passing the bot token as a param
const secret = createHash('sha256')
  .update(TOKEN)
  .digest()

function checkSignature ({ hash, ...data }) {
  const checkString = Object.keys(data)
    .sort()
    .filter((k) => data[k])
    .map(k => (`${k}=${data[k]}`))
    .join('\n');
  const hmac = createHmac('sha256', secret)
    .update(checkString)
    .digest('hex');
  return hmac === hash;
}

// Sample usage
const payload = {
  id: '424242424242',
  first_name: 'John',
  last_name: 'Doe',
  username: 'username',
  photo_url: 'https://t.me/i/userpic/320/username.jpg',
  auth_date: '1519400000',
  hash: '87e5a7e644d0ee362334d92bc8ecc981ca11ffc11eca809505'
}
checkSignature(payload)

@ImTheDeveloper I had the same issue and found out that when users do not specify their last_name the hash does not match. To fix the error, I've filtered out empty data for checkString:

const checkString = Object.keys(data)
    .sort()
    .filter((k) => data[k])
    .map(k => (`${k}=${data[k]}`))
    .join('\n');

Perfect!

…

On 17 Nov 2022, 02:35 +0000, Liubov Pitko ***@***.***>, wrote: @lub0v commented on this gist. @ImTheDeveloper I had the same issue and found out that when users do not specify their last_name the hash does not match. To fix the error, I've filtered out empty data for checkString: const checkString = Object.keys(data) .sort() .filter((k) => data[k]) .map(k => (`${k}=${data[k]}`)) .join('\n'); — Reply to this email directly, view it on GitHub or unsubscribe. You are receiving this email because you were mentioned. Triage notifications on the go with GitHub Mobile for iOS or Android.

Thanks @lub0v, I updated the gist with your suggestion :)