Which term defines a centralized mechanism for authenticating a user once and granting access to multiple services within a realm?

• A. Access Management
• B. Federation
• C. Single Sign-On
• D. Identity Store

Answer: (C)

Single Sign-On is the centralized mechanism that lets a user authenticate once and then access multiple services within the same realm without re-entering credentials. In practice, an identity provider handles the login and issues a trusted token or session. Service providers within the realm accept that token to authorize access, so the user can move between different applications seamlessly. This reduces password prompts and creates a consistent, secure gateway for access.

Access Management describes the policies and enforcement around who can access which resources, not the single-login flow itself. Identity Store is simply where credentials and identities are stored. Federation covers establishing trust between separate domains to allow cross-domain SSO, which is broader and often involves multiple realms. Within a single realm, the term that best matches the described mechanism is Single Sign-On.