Telegram user authentication in JavaScript via Web Crypto API (dependency-free)

check_authorization.js

async function validate(data, bot_token) {
  const encoder = new TextEncoder()

  const checkString = await Object.keys(data)
    .filter((key) => key !== "hash")
    .map((key) => `${key}=${data[key]}`)
    .sort()
    .join("\n")

  //console.log('computed string:', checkString)

  const tokenKey = await crypto.subtle.digest('SHA-256', encoder.encode(bot_token))
  const secretKey = await crypto.subtle.importKey("raw", tokenKey, {name: "HMAC", hash: "SHA-256"}, true, ["sign"])
  const signature = await crypto.subtle.sign("HMAC", secretKey, encoder.encode(checkString))

  const hex = [...new Uint8Array(signature)].map(b => b.toString(16).padStart(2, '0')).join('')

  //console.log('original hash:', data.hash)
  //console.log('computed hash:', hex)

  return data.hash === hex
}

@MarvinMiles Thanks for your code, it works perfect, but I found that due to the crypto.subtle, this function must be placed at the frontend webpage as this requires HTTPS to work. However, inside the function stated above, you will need to provide your bot_token. Saving credentials at the frontend may not be a safe approach. I tried to move it to the backend, but it will pops out an Error message. Cannot read property 'digest' of undefined. Do you got any other work around which it can prevent the bot_token leak?

For those who faced the same problem with me, this is the code in JS

const crypto = require("crypto");

function validate(data, token) {
  const secretKey = crypto.createHash("sha256").update(token).digest();
  const data_check_string = Object.keys(message)
    .filter((key) => key !== "hash")
    .map((key) => `${key}=${message[key]}`)
    .sort()
    .join("\n");
  const check_hash = crypto
    .createHmac("sha256", secretKey)
    .update(data_check_string)
    .digest("hex");

  return check_hash == data.hash;
}

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@MarvinMiles thanks a lot
@abc-1211 thanks , I had the same problem as you， recommended to replace "message" with "data"