The core tenet of Zero Trust is that no entity—internal or external—should be trusted by default. Every request for access must be authenticated, authorized, and encrypted based on granular access policies and continuous validation of identity, device health, location, and behavior.

ZT eliminates reliance on traditional network perimeter models (which B and A describe), focusing instead on microsegmentation and dynamic policy enforcement to prevent lateral movement within a network.

This approach is detailed in Domain 7: Infrastructure Security of the CCSK guidance. It emphasizes identity-aware access control, continuous monitoring, and contextual risk assessment as foundational elements of a secure Zero Trust framework.