Token revocation is a critical aspect of maintaining security in applications that use JWT (JSON Web Tokens) or similar tokens. This tutorial will guide you through the process of integrating token revocation into your application.

Overview

Token revocation is the process of invalidating a token after it has been issued. This ensures that even if a token is compromised, it cannot be used to gain unauthorized access to your application.

Steps for Integration

  1. Token Storage: Store the tokens in a secure, centralized location. This could be a database or an in-memory data store like Redis.
  2. Revocation List: Maintain a list of revoked tokens. When a token is revoked, add it to this list.
  3. Middleware/Interceptor: Implement middleware or an interceptor that checks the token against the revocation list on each request.
  4. Token Validation: When a token is received, validate it and check if it exists in the revocation list.
  5. Response Handling: If the token is revoked, return an appropriate response to the client, indicating that the token is no longer valid.

Example

Here's a simple example of how you might implement token revocation in a Node.js application using Express:

const express = require('express');
const jwt = require('jsonwebtoken');
const redis = require('redis');

const app = express();
const redisClient = redis.createClient();

const SECRET_KEY = 'your_secret_key';
const TOKENRevocationList = new Set();

app.post('/token', (req, res) => {
  const { username } = req.body;
  const token = jwt.sign({ username }, SECRET_KEY, { expiresIn: '1h' });

  // Store the token in Redis
  redisClient.set(token, 'revoked', redis.print);

  res.json({ token });
});

app.use((req, res, next) => {
  const token = req.headers.authorization?.split(' ')[1];

  if (!token) {
    return res.status(401).json({ error: 'No token provided' });
  }

  // Check if the token is revoked
  redisClient.get(token, (err, reply) => {
    if (err) {
      return res.status(500).json({ error: 'Internal server error' });
    }

    if (reply === 'revoked') {
      return res.status(401).json({ error: 'Token has been revoked' });
    }

    next();
  });
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

Further Reading

For more information on token revocation and JWT, you can check out the following resources:

Redis