Today’s Insights: 👈️ 

1. What is JSON Web Tokens (JWT)?

2. What is OAuth2?

3. Comparison of JWT and OAuth2

4. Industry Example from Google

I've often wondered how authentication works technically, so I really wanted to write an article about it. Everyone has probably seen "Sign in with Google," but how it works technically is not as simple as you might think. JSON Web Tokens (JWT) and OAuth2 are two important tools for web authentication. This article will explain what they are, how they are used, and the differences between them to help you decide which one to use. Let's explore the different authentication methods together and understand which technology is used when.

1. JSON Web Tokens (JWT)

JSON Web Tokens (JWT) are a compact, URL-safe means of representing claims between two parties. They are widely used for authentication and information exchange.

Core Principles and Components:

A JWT consists of three parts: Header, Payload, and Signature. The Header typically consists of the token type (JWT) and the signing algorithm (e.g., HMAC SHA256). The Payload contains the claims, which are statements about an entity (typically, the user) and additional data. The Signature ensures that the token hasn't been altered.

Common Use Cases (JWT):

JWTs are commonly used for authentication in web applications, enabling single sign-on (SSO). They are also used for secure data transmission, as they can be easily signed and verified, ensuring the integrity and authenticity of the information.

• Pros:

  • Compact and URL-safe: Easy to pass in HTML and HTTP environments.

  • Self-contained: Contains all necessary information about the user, reducing the need for frequent database queries.

  • Stateless: Server does not need to store session information, improving scalability.

• Cons:

  • Security risks: If not implemented correctly, JWTs can be susceptible to various attacks, such as token theft.

  • No built-in expiration management: Developers must implement token expiration and revocation mechanisms.

In summary, JWT is a powerful tool for web authentication and secure information exchange, with clear advantages in scalability and efficiency, balanced by the need for careful security implementation.

2. OAuth2

OAuth2 is an authorization framework that enables applications to obtain limited access to user accounts on an HTTP service, such as Facebook, GitHub, or Google. It is designed to work with the HTTP protocol and allows third-party applications to access user data without exposing user credentials.

Core Principles and Components:

OAuth2 operates based on four roles: Resource Owner, Client, Resource Server, and Authorization Server. The Resource Owner is typically the end-user. The Client is the application requesting access. The Resource Server hosts the protected resources. The Authorization Server issues the access tokens after authenticating and authorizing the Resource Owner.

Common Use Cases (OAuth2):

OAuth2 is commonly used for third-party logins (e.g., "Login with Google"), providing limited access to user data for third-party apps, and enabling secure API access across different services.

• Pros:

  • Enhanced security: Users can authorize third-party access without sharing passwords.

  • Granular access control: Scopes allow fine-grained permission levels.

  • Standardized framework: Widely adopted, making integration with major services straightforward.

• Cons:

  • Complexity: Can be challenging to implement correctly due to its detailed specification.

  • Implementation variations: Different providers may have slightly different implementations, causing interoperability issues.

  • Token management: Requires careful handling of tokens and refresh mechanisms to maintain security.

In summary, OAuth2 is a robust authorization framework that facilitates secure, granular access to user resources, balancing its complexity and the need for careful token management with its security benefits and widespread adoption.

3. Comparison of JWT and OAuth2

Differences in Application:

• JWT is primarily used for authentication and secure data exchange. It is self-contained and stateless, ideal for microservices and single sign-on (SSO) implementations.

• OAuth2 is an authorization framework that allows third-party applications to access user resources without sharing passwords, commonly used for third-party logins and API access control.

Security and Best Practices:

• JWT:

  • Ensure secure signing and verification.

  • Implement token expiration and revocation mechanisms.

  • Avoid storing sensitive data in the payload.

• OAuth2:

  • Use secure storage for tokens.

  • Implement refresh tokens for long-lived sessions.

  • Define scopes to limit access permissions.

When to Use Which Technology?

• Use JWT for authentication and scenarios where stateless, scalable token management is needed.

• Use OAuth2 for authorization, especially when third-party applications require limited access to user resources without exposing credentials.

In summary, JWT is best for authentication and stateless communication, while OAuth2 excels in authorization and controlled resource access.

4. Industry Example: Google

Google uses OAuth2 as an authorization framework to enable secure access to its APIs and services without sharing user credentials. When a user wants to allow a third-party application to access their Google account, OAuth2 facilitates this by providing a secure token that grants the application specific access rights. This token can be used by the application to access Google services like Gmail, Google Drive, and Google Cloud APIs, ensuring the user's credentials remain private and secure.

Source: https://cloud.google.com/docs/authentication