Is it possible to create product keys for my electron application?

Question

I want to build a desktop application and be able to publish product keys or serial numbers.Before the user can use the application he will be requested to enter the product key/serial number.

Similar to Microsoft Office when they provide keys like XXXX-XXXX-XXXX-XXXX

The idea I have is to sell the app based on licenses and providing product key for every device seems more professional than accounts (usernames and passwords).

so my questions are:

1) Is it possible to accomplish this with electron?

2) Can you advice me wether I should go for serial numbers (if it is doable) or accounts? or are there better options?

3) if you answered the second question. Please state why?

Answer 1

Edit for 2021: I'd like to revise this answer, as it has generated a lot of inquiries on the comparison I made between license keys and user accounts. I previously would almost always recommended utilizing user accounts for licensing Electron apps, but I've since changed my position to be a little more nuanced. For most Electron apps, license keys will do just fine.

Adding license key (synonymous with product key) validation to an Electron app can be pretty straight forward. First, you would want to somehow generate a license key for each user. This can be done using cryptography, or it can be done by generating a 'random' license key string and storing it in a database and then building a CRUD licensing server that can verify that a given license key is "valid."

For cryptographic license keys, you can take some information from the customer, e.g. their order number or an email address, and create a 'signature' of it using RSA cryptography. Using Node, that would look something like this:

const crypto = require('crypto')

// Generate a new keypair
const { privateKey, publicKey } = crypto.generateKeyPairSync('rsa', {
  // Using a larger key size, such as 2048, would be more secure
  // but will result in longer signatures.
  modulusLength: 512,
  privateKeyEncoding: { type: 'pkcs1', format: 'pem' },
  publicKeyEncoding: { type: 'pkcs1', format: 'pem' },
})

// Some data we're going to use to generate a license key from
const data = '[email protected]'

// Create a RSA signer
const signer = crypto.createSign('rsa-sha256')
signer.update(data)

// Encode the original data
const encoded = Buffer.from(data).toString('base64')

// Generate a signature for the data
const signature = signer.sign(privateKey, 'hex')

// Combine the encoded data and signature to create a license key
const licenseKey = `${encoded}.${signature}`

console.log({ privateKey, publicKey, licenseKey })

Then, to validate the license key within your Electron app, you would want to cryptographically 'verify' the key's authenticity by embedding the public (not the private!) key generated above into your application code base:

// Split the license key's data and the signature
const [encoded, signature] = licenseKey.split('.')
const data = Buffer.from(encoded, 'base64').toString()

// Create an RSA verifier
const verifier = crypto.createVerify('rsa-sha256')
verifier.update(data)

// Verify the signature for the data using the public key
const valid = verifier.verify(publicKey, signature, 'hex')

console.log({ valid, data })

Generating and verifying the authenticity of cryptographically signed license keys like this will work great for a lot of simple licensing needs. They're relatively simple, and they work great offline, but sometimes verifying that a license key is 'valid' isn't enough. Sometimes requirements dictate that license keys are not perpetual (i.e. 'valid' forever), or they call for more complicated licensing systems, such as one where only a limited number of devices (or seats) can use the app at one time. Or perhaps the license key needs a renewable expiration date. That's where a license server can come in.

A license server can help manage a license's activation, expirations, among other things, such as user accounts used to associate multiple licenses or feature-licenses with a single user or team. I don't recommend user accounts unless you have a specific need for them, e.g. you need additional user profile information, or you need to associate multiple licenses with a single user.

But in case you aren't particularly keen on writing and maintaining your own in-house licensing system, or you just don't want to deal with writing your own license key generator like the one above, I’m the founder of a software licensing API called Keygen which can help you get up and running quickly without having to write and host your own license server. :)

Keygen is a typical HTTP JSON API service (i.e. there’s no software that you need to package with your app). It can be used in any programming language and with frameworks like Electron.

In its simplest form, validating a license key with Keygen is as easy as hitting a single JSON API endpoint (feel free to run this in a terminal):

curl -X POST https://api.keygen.sh/v1/accounts/demo/licenses/actions/validate-key \
  -d '{
        "meta": {
          "key": "C1B6DE-39A6E3-DE1529-8559A0-4AF593-V3"
        }
      }'

I recently put together an example of adding license key validation, as well as device activation and management, to an Electron app. You can check out that repo on GitHub: https://github.com/keygen-sh/example-electron-license-activation.

I hope that answers your question and gives you a few insights. Happy to answer any other questions you have, as I've implemented licensing a few times now for Electron apps. :)

Answer 2

Yes, it is possible.

I myself desired this feature, and I found related solutions such as paid video tutorials, online solutions [with Keygen], and other random hacks, but I wanted something that is offline and free, so I created my own repository for myself/others to use. Here's how it works.

Overview

1. Install secure-electron-license-keys-cli. (ie. npm i -g secure-electron-license-keys-cli).
2. Create a license key by running secure-electron-license-keys-cli. This generates a public.key, private.key and license.data.
3. Keep private.key safe, but stick public.key and license.data in the root of your Electron app.
4. Install secure-electron-license-keys. (ie. npm i secure-electron-license-keys).
5. In your main.js file, review this sample code and add the necessary binding.

const {
    app,
    BrowserWindow,
    ipcMain,
} = require("electron");
const SecureElectronLicenseKeys = require("secure-electron-license-keys");
const path = require("path");
const fs = require("fs");
const crypto = require("crypto");

// Keep a global reference of the window object, if you don't, the window will
// be closed automatically when the JavaScript object is garbage collected.
let win;

async function createWindow() {

    // Create the browser window.
    win = new BrowserWindow({
        width: 800,
        height: 600,
        title: "App title",
        webPreferences: {
            preload: path.join(
                __dirname,
                "preload.js"
            )
        },
    });

    // Setup bindings for offline license verification
    SecureElectronLicenseKeys.mainBindings(ipcMain, win, fs, crypto, {
        root: process.cwd(),
        version: app.getVersion(),
    });

    // Load app
    win.loadURL("index.html");

    // Emitted when the window is closed.
    win.on("closed", () => {
        // Dereference the window object, usually you would store windows
        // in an array if your app supports multi windows, this is the time
        // when you should delete the corresponding element.
        win = null;
    });
}

// This method will be called when Electron has finished
// initialization and is ready to create browser windows.
// Some APIs can only be used after this event occurs.
app.on("ready", createWindow);

// Quit when all windows are closed.
app.on("window-all-closed", () => {
    // On macOS it is common for applications and their menu bar
    // to stay active until the user quits explicitly with Cmd + Q
    if (process.platform !== "darwin") {
        app.quit();
    } else {
        SecureElectronLicenseKeys.clearMainBindings(ipcMain);
    }
});

6. In your preload.js file, review the sample code and add the supporting code.

const {
    contextBridge,
    ipcRenderer
} = require("electron");
const SecureElectronLicenseKeys = require("secure-electron-license-keys");

// Expose protected methods that allow the renderer process to use
// the ipcRenderer without exposing the entire object
contextBridge.exposeInMainWorld("api", {
    licenseKeys: SecureElectronLicenseKeys.preloadBindings(ipcRenderer)
});

7. Review the sample React component how you can verify the validity of your license, and act accordingly within your app.

import React from "react";
import {
  validateLicenseRequest,
  validateLicenseResponse,
} from "secure-electron-license-keys";

class Component extends React.Component {
  constructor(props) {
    super(props);

    this.checkLicense = this.checkLicense.bind(this);
  }

  componentWillUnmount() {
    window.api.licenseKeys.clearRendererBindings();
  }

  componentDidMount() {
    // Set up binding to listen when the license key is
    // validated by the main process
    const _ = this;

    window.api.licenseKeys.onReceive(validateLicenseResponse, function (data) {
      console.log("License response:");
      console.log(data);
    });
  }

  // Fire event to check the validity of our license
  checkLicense(event) {
    window.api.licenseKeys.send(validateLicenseRequest);
  }

  render() {
    return (
      <div>
        <button onClick={this.checkLicense}>Check license</button>
      </div>
    );
  }
}

export default Component;

You are done!

Further detail

To explain further, the license is validated by a request from the client (ie. front-end) page. The client sends an IPC request to the main (ie. backend) process via this call (window.api.licenseKeys.send(validateLicenseRequest)).

Once this call is received by the backend process (which was hooked up because we set it up with this call (SecureElectronLicenseKeys.mainBindings)), the library code tries to decrypt license.data with public.key. Regardless if this succeeds or not, the success status is sent back to the client page (via IPC).

How to limit license keys by version

What I've explained is quite limited because it doesn't limit the versions of an app you might give to a particular user. secure-electron-license-keys-cli includes flags you may pass when generating the license key to set particular major/minor/patch/expire values for a license.

If you wanted to allow major versions up to 7, you could run the command to generate a license file like so: secure-electron-license-keys-cli --major "7"

If you wanted to allow major versions up to 7 and expire on 2022-12-31, you could run the command to generate a license file like so: secure-electron-license-keys-cli --major "7" --expire "2022-12-31"

If you do run these commands, you will need to update your client page in order to compare against them, ie:

window.api.licenseKeys.onReceive(validateLicenseResponse, function (data) {

    // If the license key/data is valid
    if (data.success) {

        if (data.appVersion.major <= data.major &&
            new Date() <= Date.parse(data.expire)) {

            // User is able to use app
        } else {
            // License has expired
        }
    } else {
        // License isn't valid
    }
});

The repository page has more details of options but this should give you the gist of what you'll have to do.

Limitations

This isn't perfect, but will likely handle 90% of your users. This doesn't protect against:

• Someone decompiling your app and making their own license to use/removing license code entirely
• Someone copying a license and giving it to another person

There's also the concern how to run this library if you are packaging multiple or automated .exes, since these license files need to be included in the source. I'll leave that up to the creativity of you to figure out.

Extra resources / disclaimers

I built all of the secure-electron-* repositories mentioned in this question, and I also maintain secure-electron-template which has the setup for license keys already pre-baked into the solution if you need something turn-key.

Answer 3

1. YES but concerning the software registration mechanism, IT IS HARD and it needs a lot of testing too.
2. If 90% of your users have internet access you should definitely go with the user accounts or some OAUTH 2.0 Plug and play thing (login with facebook/gmail/whatever)
3. I built a software licensing architecture from scratch using crypto and the fs module , and it was quite a journey (year) !

Making a good registration mechanism for your software from scratch is not recommended , electron makes it harder because the source code is relatively exposed.

That being said , if you really wanna go that way , bcrypt is good at this (hashs), you need a unique user identifier to hash , you also need some kind of persistence (preferably a file ) where you can store the user license , and you need to hide the salt that you are using for hashing either by hashing the hash... or storing small bits of it in separate files.

this will make a good starting point for licensing but it's far from being fully secured.

Hope it helps !

Answer 4

There are many services out there which help you add license key based software licensing to your app. And to ensure your customers don't reuse the key, you would need a strong device fingerprinting algorithm.

You can try out Cryptlex. It offers a very robust licensing solution with advanced device fingerprinting algo. You can check out the Node.js example on Github to add licensing to your electron app.