Authentication Best Practices

Secure authentication is the foundation of application security. Learn how to implement it correctly.

Authentication Methods

Choosing the right approach:

• Session-based with server-side storage
• Token-based (JWT) for stateless auth
• OAuth 2.0 for third-party integration

JWT Implementation

Token Structure

1. Header - algorithm and type
2. Payload - claims and data
3. Signature - verification
   • HMAC algorithms
   • RSA for distributed systems
4. Expiration handling

Copy
1// Example: JWT verification middleware
2const jwt = require("jsonwebtoken");
3
4function authenticate(req, res, next) {
5  const token = req.headers.authorization?.split(" ")[1];
6
7  if (!token) {
8    return res.status(401).json({ error: "No token provided" });
9  }
10
11  try {
12    const decoded = jwt.verify(token, process.env.JWT_SECRET);
13    req.user = decoded;
14    next();
15  } catch (error) {
16    res.status(401).json({ error: "Invalid token" });
17  }
18}

Password Security

"The only secure password is the one you can't remember."

• Troy Hunt

Common Mistakes

Avoid these pitfalls:

• Never store plaintext passwords
• Use secure session cookies (HttpOnly, Secure)
• Roll your own crypto Use established libraries

Auth0 Blog has excellent authentication resources!