Which access control mechanism allows for multiple systems to use a central authentication server (CAS)...

In CEH v13 Module 05: System Hacking, and Module 14: Access Control, Identity Management, and Cryptography, Single Sign-On (SSO) is defined as a system that allows users to authenticate once and gain access to multiple systems without re-entering credentials.

SSO uses a Central Authentication Server (CAS).

Common technologies: Kerberos, OAuth, SAML, AD Federation Services.

Improves user convenience and centralized credential management.