The five pillars of Cybersecurity are availability, integrity, nonrepudiation, confidentiality, and which?

• A. Encryption
• B. Authentication
• C. Privacy
• D. Access Control

Answer: (B)

Verifying identity is the element that completes the set by enabling you to know who is performing actions. Authentication is about proving that a user or device really is who it claims to be, which is essential for traceability and nonrepudiation. When you can reliably establish identity, you can attribute actions to a specific entity, create solid audit trails, and prevent someone from denying a past action. Encryption protects confidentiality and helps guard data integrity, but it’s a technique, not a pillar by itself. Privacy is an objective tied to confidentiality, and access control is a mechanism to enforce permissions—not a standalone pillar. Authentication, by providing verified identity, is what makes accountability and nonrepudiation possible alongside availability, integrity, and confidentiality.