A federated identity in information technology is the means of linking a person's electronic identity and attributes, stored across multiple distinct identity management

Identity management

Identity management is a broad administrative area that deals with identifying individuals in a system and controlling access to the resources in that system by placing restrictions on the established identities of the individuals.Identity management is multidisciplinary and covers many...

 systems.

Related to federated identity is single sign-on

Single sign-on

Single sign-on is a property of access control of multiple related, but independent software systems. With this property a user logs in once and gains access to all systems without being prompted to log in again at each of them...

 (SSO), in which a user's single authentication

Authentication

Authentication is the act of confirming the truth of an attribute of a datum or entity...

 ticket, or token, is trusted across multiple IT systems or even organizations. SSO is a subset of federated identity management

Federated identity management

In information technology, Federated Identity Management amounts to having a common set of policies, practices and protocols in place to manage the identity and trust into IT users and devices across organizations....

, as it relates only to authentication

Authentication

Authentication is the act of confirming the truth of an attribute of a datum or entity...

and is understood on the level of technical interoperability.