What is 'single sign-on' (SSO), and how does it relate to authorization?

Question

Aryan Kumar · Answer

Single Sign-On (SSO) is a centralized authentication and authorization mechanism that allows a user to access multiple applications or services 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 then seamlessly access various resources without being prompted for credentials again during the same session.

SSO systems are primarily focused on authentication, but they have a strong relationship with authorization in the context of access control. Here's how SSO relates to authorization:

1. Authentication vs. Authorization:

Authentication: SSO is primarily concerned with authentication, which is the process of verifying the identity of a user. When a user logs in through SSO, the system authenticates their identity, often by checking a central identity provider (IdP) or directory service.

Authorization: Authorization, on the other hand, deals with permissions and access control. Once a user is authenticated, authorization determines what actions and resources the user is allowed to access based on their role, privileges, or other criteria.

2. SSO and Authorization in Practice:

While SSO focuses on authentication, it often integrates with authorization systems. After a user is authenticated through SSO, the SSO system can convey information about the user's identity and roles to the applications or services they access.

The receiving applications can then use this identity information to make authorization decisions. For example, the application can check whether the user has the necessary permissions to perform a specific action or access certain resources.

3. Role-Based Access Control (RBAC):

SSO systems often use Role-Based Access Control (RBAC) or similar mechanisms to manage authorization. In an RBAC system, users are assigned roles, and each role has a set of associated permissions. After SSO authentication, the application can map the user's role(s) to the appropriate permissions.

4. Federated Authorization:

In some cases, SSO systems also support federated authorization, where authorization decisions are made by external authorization services or policies. These external authorization systems can use information provided by the SSO system to make access control decisions.

5. Fine-Grained Authorization:

While SSO can handle basic authorization needs based on user roles, more complex scenarios requiring fine-grained authorization often involve additional authorization mechanisms and policies. This might include attribute-based access control (ABAC) or custom authorization logic within individual applications.

In summary, SSO primarily addresses authentication, simplifying the login process for users across multiple applications. However, SSO systems often work in conjunction with authorization mechanisms to enable seamless and secure access control. The identity and role information provided by SSO can be used by applications to make authorization decisions, ensuring that users only access resources and perform actions they are permitted to use.

forum

What is 'single sign-on' (SSO), and how does it relate to authorization?

Can you answer this question?

1 Answers