What Is SSO and How Does it Work?

SSO stands for Single Sign-On. It is an authentication mechanism that allows users to access multiple applications or systems with a single set of login credentials. Instead of requiring users to remember and enter separate usernames and passwords for each application, SSO enables them to log in once and gain access to all the authorized systems seamlessly.

Here’s how SSO typically works:

1. The user initiates the login process: The user attempts to access a protected application or system. Instead of providing their credentials directly to that application, they are redirected to the SSO service.
2. SSO authentication: The SSO service verifies the user’s identity by requesting their login credentials, such as username and password or other forms of authentication, like biometric data or a security token.
3. Authentication token generation: Upon successful authentication, the SSO service generates a secure token that represents the user’s authenticated session. This token is usually encrypted and digitally signed to ensure its integrity.
4. Token sent to application: The SSO service redirects the user back to the requested application, and the token is passed along with the request.
5. Application validation: The application receives the token and validates it with the SSO service. This verification ensures that the token is legitimate and hasn’t been tampered with.
6. User access granted: If the token is valid, the application grants the user access without requiring them to re-enter their credentials. The user can now navigate through the application or system as an authenticated user.
7. Single logout: When the user decides to log out, the SSO service is notified and can terminate the user’s session across all the applications and systems associated with the SSO service. This eliminates the need to log out individually from each application.

The benefits of SSO include improved user experience, increased security, and simplified administration. Users don’t have to remember multiple passwords, reducing the risk of weak or reused passwords. From an administrative perspective, it allows for centralized user management and easier provisioning and de-provisioning of access to applications.

SSO can be implemented using various protocols such as SAML (Security Assertion Markup Language), OAuth (Open Authorization), OpenID Connect, or proprietary protocols provided by specific vendors. The specific implementation may vary depending on the chosen protocol and the systems involved in the SSO ecosystem.