JWT vs OAuth Comparison

1. Introduction

In modern web applications, authentication and authorization are critical components. This lesson compares JWT (JSON Web Tokens) with OAuth (Open Authorization), two popular methods for handling these processes.

2. What is JWT?

2.1 Key Features of JWT

• Compact: JWTs can be sent via URL, POST parameter, or inside an HTTP header.
• Self-contained: JWTs contain all the necessary information about the user and can be verified without querying a database.
• Secure: JWTs can be signed and encrypted for added security.

2.2 JWT Structure

A JWT consists of three parts: Header, Payload, and Signature.

{
  "alg": "HS256",
  "typ": "JWT"
}
        

Example Payload:

{
  "sub": "1234567890",
  "name": "John Doe",
  "iat": 1516239022
}
        

Signature Example:

HMACSHA256(
  base64UrlEncode(header) + "." +
  base64UrlEncode(payload),
  your-256-bit-secret
)
        

3. What is OAuth?

3.1 Key Features of OAuth

• Delegated Access: OAuth allows users to grant access to their resources without sharing credentials.
• Token-based: OAuth issues access tokens to clients to access resources on behalf of the user.
• Granular Permissions: Users can control the level of access provided to applications.

3.2 OAuth Flow

1. User requests access via the client application.
2. The client redirects the user to the authorization server.
3. User authenticates and authorizes the client.
4. The authorization server redirects to the client with an authorization code.
5. The client requests an access token using the authorization code.
6. The authorization server responds with an access token.
7. The client uses the access token to access protected resources.
        

4. Comparison between JWT and OAuth

4.1 Purpose

JWT is primarily used for authentication, while OAuth is designed for authorization.

4.2 Complexity

JWT is simpler to implement as it doesn't require a separate authorization server, whereas OAuth involves complex interactions between multiple parties.

4.3 Use Cases

• Use JWT for stateless authentication in APIs.
• Use OAuth for third-party access to user data.

5. Best Practices

• Keep your JWT secret safe and rotate it regularly.
• Use short expiration times for tokens to reduce risk.
• Validate tokens on every request to ensure they are still valid.
• Use scopes in OAuth to limit access levels for tokens.

6. FAQ