Identity management refers to the policies, processes, and technologies that establish user identities and enforce rules about access to digital resources. In a campus setting, many information systems–such as e-mail, learning management systems, library databases, and grid computing applications–require users to authenticate themselves (typically with a username and password). An authorization process then determines which systems an authenticated user is permitted to access. With an enterprise identity management system, rather than having separate credentials for each system, a user can employ a single digital identity to access all resources to which the user is entitled.
Federated identity management permits extending this approach above the enterprise level, creating a trusted authority for digital identities across multiple organizations. In a federated system, participating institutions share identity attributes based on agreed-upon standards, facilitating authentication from other members of the federation and granting appropriate access to online resources. This approach streamlines access to digital assets while protecting restricted resources. [Source: 7 Things You Should Know About Federated Identity Management]