What does the principle of "defense in depth" entail?

The principle of "defense in depth" entails employing multiple layers of security controls to protect an organization's assets. This approach recognizes that no single security measure is entirely foolproof, and therefore, combining various security strategies enhances overall protection. By creating a layered security environment, an organization can mitigate the risk of threats and vulnerabilities, as an attacker would need to bypass multiple defenses to successfully compromise the system.

In practice, defense in depth might include a combination of physical security measures, firewalls, intrusion detection systems, encryption, access controls, and employee training. Each layer serves as a barrier that contributes to the overall security posture of the organization.

This strategy contrasts sharply with using a single security measure, which can leave significant gaps in protection. It also moves beyond focusing solely on network security, recognizing that threats can arise from various areas, including application, physical, and operational security. Moreover, choosing to maximize user convenience over security would undermine the principles of defense in depth, as it prioritizes ease of use at the potential expense of robust security measures.