In modern web applications, implementing secure authentication is of utmost importance. JSON Web Tokens (JWT) have become a popular choice for implementing stateless authentication. However, there are cases where you may want to add an extra layer of security by allowing only one-time use of JWTs. In this blog post, we will explore how to implement one-time use tokens with JWT authentication.

Why One-Time Use Tokens?

One-time use tokens provide an additional security measure by ensuring that a token can only be used once. This approach mitigates the risk of token theft or misuse and enhances the overall security of the application.

Implementing One-Time Use Tokens

To implement one-time use tokens with JWT authentication, we can utilize the concept of token revocation. By keeping track of revoked tokens, we can validate each token and ensure it has not been used before.

Steps to Implement

1. Generate a unique token identifier for each token issued.
2. Store the token identifier in a persistent data store (such as a database) alongside additional information like the user’s ID and expiration time.
3. When a token is presented for authentication, check if the token identifier is present in the persistent store.
4. If the token identifier is found, reject the token and deny access.
5. If the token identifier is not found, proceed with the normal JWT authentication flow.
6. Once the token is used or expired, mark the token identifier as revoked in the persistent store.

Example Implementation in Node.js

Here’s an example implementation of one-time use tokens with JWT authentication in Node.js using the jsonwebtoken library:

const jwt = require('jsonwebtoken');
const revokedTokens = new Set();

function generateToken(userId) {
  const token = jwt.sign({ userId }, 'secret', { expiresIn: '15m' });
  const tokenId = // generate a unique token identifier (e.g., UUID)
  const expirationTime = new Date().getTime() + 900000; // 15 minutes
  // store tokenId, userId, and expirationTime in the database
  return token;
}

function authenticateToken(token) {
  const payload = jwt.verify(token, 'secret');
  const tokenId = // obtain the token identifier from the payload
  // check if tokenId is in revokedTokens or in the database
  if (revokedTokens.has(tokenId) || isTokenRevokedInDb(tokenId)) {
    throw new Error('Token is revoked');
  }
  // proceed with normal authentication flow
}

function revokeToken(tokenId) {
  revokedTokens.add(tokenId);
  // mark tokenId as revoked in the database
}

function isTokenRevokedInDb(tokenId) {
  // check if tokenId is marked as revoked in the database
  // return true or false
}

In this example, we use a Set to keep track of revoked tokens in memory, but it’s essential to store this information in a persistent store like a database for real-world scenarios.

Conclusion

Implementing one-time use tokens with JWT authentication adds an extra layer of security to your web application. By carefully managing token revocation and checking for revoked tokens during authentication, you can enhance the overall security and protect against token misuse.