What is the difference between federated identity management (FIM) and single sign-on (SSO)?
Single sign-on (SSO) is an access control technique that enables a user authentication to be used to sign on to multiple but related applications. The SSO service is applicable only on a single organization. Whereas federated identity management (FIM) is an access control that supports authentication of users across different organizations. However, the idea and the principle of the two is the same and that is to minimize authentication overheads.
The FIM extends SSO principle by enabling a set of credentials to get access to multiple systems across different organizations. Unlike SSO, users in FIM may be required to enter their credentials multiple times but the credentials will remain the same across all members of the federation.