What does the concept of "defense in depth" refer to?

The concept of "defense in depth" refers to a comprehensive approach with multiple security layers, which is essential in creating a robust security posture. This strategy is designed to protect data and systems by utilizing different security measures across various levels within an organization.

By implementing multiple layers of security, such as physical security, network security, application security, and user education, the idea is to create redundancies that can thwart or mitigate attacks, making it more difficult for unauthorized users to access sensitive information or systems. If one layer is breached, additional layers provide continued protection, thus reducing the risk of total compromise.

This approach recognizes that no single security measure is foolproof and emphasizes a holistic view of security that addresses potential vulnerabilities at all levels, rather than relying on a singular approach or control. The other options do not encapsulate this broader methodology; a single layer, solely physical measures, or minimal interventions do not provide adequate protection against the complex threats faced in today’s digital landscape.