Describes the technologies standards and use cases that enable portability of identity information across autonomous security domains.

• A. Cross-Domain Connections
• B. Directory Services
• C. Cloud to On-Premise Connections
• D. Federation of Identity (FIdM)

Answer: (D)

Identity federation is the mechanism that allows identity information to move and be trusted across independent security domains. It creates a trust relationship between domains so a user authenticated in one domain can access resources in another without re-entering credentials. Standards like SAML 2.0 and WS-Federation define how authentication assertions and user attributes are exchanged, while modern approaches use OAuth 2.0 and OpenID Connect for broader cloud and API scenarios. Practical uses include single sign-on across partner applications, granting employees access to cloud services using their home organization credentials, and enabling cross-organizational collaboration where identities are managed centrally but can be used in multiple domains. The other options describe networking links, local directory storage, or hybrid connectivity, none of which inherently address portable identity and cross-domain trust in the way federation does.