Which security measure involves layering defenses to protect a network?

The concept of "defense in depth" refers to a security strategy that implements multiple layers of security controls throughout an information technology system. This approach aims to provide comprehensive protection by not relying solely on a single security mechanism but rather combining various measures, such as firewalls, intrusion detection systems, antivirus software, and encryption.

By utilizing defense in depth, if one layer of security fails, others remain in place to thwart potential attacks, thus reducing the risk of a security breach significantly. This multi-faceted approach enhances the overall resilience of a network against various threats and vulnerabilities. The effectiveness of this strategy lies in its redundancy and diversity; each layer addresses different potential weaknesses, making systems harder to penetrate.

In contrast, encryption serves a specific purpose of safeguarding data by converting it into a secure format that unauthorized users cannot read. Vigilance relates to maintaining awareness and monitoring of security threats, while firewalls act as a barrier to control incoming and outgoing network traffic. While these elements are important to security, they do not encapsulate the holistic, layered methodology represented by defense in depth.