JWT Tokens Complete Guide

Introduction

• Welcome to Chai aur Code channel.
• This video is a complete guide on JWT tokens.
• By the end, you'll have complete knowledge about JWT including pros, cons, use cases, and internal mechanisms.
• This video is more in-depth compared to the practical guide in the backend series.

Overview

• Notes, FAQs, and diagrams will be covered.
• We'll explore the official JWT website and documentation (jwt.io).
• Discuss public-private cryptography and stateless vs stateful concepts.

Key Concepts

Public-Private Cryptography

• Involves two keys: Public key (distributable) and Private key (kept secure).
• JWT operates using similar concepts.

Stateless vs Stateful

• Stateless: State is not stored in a database/file.
• Stateful: State is stored and managed.

JWT Overview

What is JWT?

• JSON Web Token (JWT) is an encrypted token for authentication and authorization.
• Composed of three parts: Header, Payload, Signature.
• Uses various encryption algorithms (e.g., HS256).
• Three components: Header (Algorithm info), Payload (Data), Signature (Verification).

Structure of JWT

• Header: Contains algorithm and token type.
• Payload: Contains user information like ID, issued at time (iat), expiry time (exp), etc.
• Signature: Ensures data is not manipulated.

JWT Storage & Security

• Methods: Local Storage, Session Storage, Cookies with HTTP flags.
• Best practice: Short expiration time (e.g., 15 minutes), use Refresh Tokens.

Authentication vs Authorization

Definitions:

• Authentication: Verifying the identity (using credentials like username and password).
• Authorization: Granting access to resources based on identity.

Use Cases:

• Single Sign-On (SSO): Allows accessing multiple services with one authentication.
• Server-to-Server communication.

Common Questions:

• JWT Usage: Authentication, Authorization, Information exchange.
• Invalidate JWT: Define expiration time, use Refresh Tokens.

Refresh Tokens

Workflow:

• Client requests access and receives JWT and Refresh Token.
• Access Token is short-lived; Refresh Token is used to generate new Access Tokens.

JWT vs Sessions

Stateless (JWT Tokens)

• Can be scaled efficiently.
• No database access required for each request.

Stateful (Sessions)

• Involves storing session ID in cookies and validating with the database.
• Requires extra database calls for validation.

Practical Insights

Implementing JWT

• Easily implementable in various frameworks (Node.js, Django, Ruby on Rails, etc.).
• Always ensure private keys and tokens are securely managed.

Security Practices

• Use strong secrets and keys.
• Shorten token lifespan.
• Store tokens securely.

Conclusion

• JWT is a robust and secure method for authentication and authorization.
• Well-implemented JWT mechanisms can outperform traditional session-based approaches.
• Subscribe, leave comments for more topics.

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Thank you for watching!