Authentication¶

Overview¶

Authentication is the process of verifying the identity of a user or service. In distributed systems, authentication must be secure, scalable, and often stateless to allow for horizontal scaling.

Key Concepts¶

1. JWT (JSON Web Tokens)¶

Stateless authentication mechanism where the user's identity is encoded in a signed token.

• Strengths: No need for server-side sessions, works well in microservices.
• Weaknesses: Hard to revoke before expiration, token size can increase latency.

2. OAuth2 & OpenID Connect¶

Industry-standard protocols for authorization and authentication.

• OAuth2: Focuses on authorization (accessing resources).
• OIDC: An identity layer on top of OAuth2.

3. SSO (Single Sign-On)¶

Allows a user to log in once and access multiple related systems.

• Technologies: SAML, Okta, Auth0.

Trade-offs & Considerations¶

• Stateful vs. Stateless: Stateless (JWT) is easier to scale but harder to manage (revocation). Stateful (Sessions) is easier to manage but requires a shared session store (like Redis).
• Security: Always use HTTPS. Protect against CSRF, XSS, and Brute Force attacks.
• MFA (Multi-Factor Authentication): Adding an extra layer of security (e.g., TOTP, SMS).

Further Reading¶

• Auth0: The Ultimate Guide to JWT
• OAuth 2.0 Simplified
• OWASP Authentication Cheat Sheet