Single Sign-On (SSO) Explained

Key Concepts

Single Sign-On (SSO) is a session and user authentication service that permits a user to use one set of login credentials to access multiple applications. The main concepts related to SSO include:

1. Central Authentication Service (CAS)
2. Federated Identity Management
3. Token-Based Authentication

1. Central Authentication Service (CAS)

CAS is a server protocol that handles user authentication centrally for multiple applications. It acts as a trusted intermediary that verifies user credentials and issues tickets to access other services.

Example: When you log into a university portal, CAS verifies your credentials and allows you to access various services like the library, email, and course management systems without needing to log in separately to each one.

2. Federated Identity Management

Federated Identity Management involves sharing identity information across security domains. It allows users to authenticate once and access multiple services across different organizations or domains.

Example: Using your Google account to log into a third-party application is an example of federated identity management. Google acts as the identity provider, and the third-party application trusts Google to authenticate the user.

3. Token-Based Authentication

Token-Based Authentication uses tokens to authenticate users and grant access to resources. These tokens are typically issued after the user successfully logs in and are used to verify the user's identity for subsequent requests.

Example: When you log into a website and receive a session cookie, that cookie acts as a token. For each subsequent request, the server verifies the token to ensure you are still authenticated and authorized to access the requested resource.

Conclusion

Understanding Single Sign-On (SSO) involves grasping the concepts of Central Authentication Service (CAS), Federated Identity Management, and Token-Based Authentication. By implementing SSO, organizations can enhance user experience, improve security, and streamline access management across multiple applications.