Which of the following security principles most likely requires validation before allowing traffic between systems?

Zero Trust architecture is based on the principle of "never trust, always verify," meaning all traffic between systems must be authenticated and authorized before communication is allowed, regardless of network location.

Policy enforcement (A) is important but broader. Authentication (B) is a component of Zero Trust, and confidentiality (D) refers to data protection, not access validation.

Zero Trust is a modern security framework emphasized in Security Architecture for securing enterprise environments【6:Chapter 3†CompTIA Security+ Study Guide】.