From CSO Identity & Risk -
By John K. Waters
The ABCs of Identity Management
Providing IT managers with tools and technologies for controlling user access to critical information within an organization.
What is Federated Identity Management?
Federation lets you share digital IDs with trusted partners. It's an authentication-sharing mechanism designed to allow users to employ the same user name, password or other ID to gain access to more than one network. It's what is known as a "single sign-on." A single sign-on standard lets people who verify their identity on one network or website carry over that authenticated status when moving to another. The model works only among cooperating organizations—known as trusted partners—that essentially vouch for each other's users.
The federated model relies on the security assertion markup language specification, better known as SAML (pronounced "SAM-el"). This open specification defines an XML framework for exchanging security assertions among security authorities. SAML was developed by the Liberty Alliance, an organization formed to establish guidelines and best practices for federated ID management. The Sun Microsystems-backed group developed SAML to achieve interoperability across different vendor platforms that provide authentication and authorization services.
Microsoft and IBM have established a rival ID management federation standard: the WS-Federation specification. This spec is also designed to provide a standardized way for companies to share user and machine identities among disparate authentication and authorization systems and across corporate boundaries.
The federation model can simplify administration and enable companies to extend ID and access management to third-party users and third-party services.