Which of the following is NOT typically included in a layered defense strategy?

A layered defense strategy, often referred to as defense in depth, involves implementing multiple security measures at different levels to protect against various threats. Each layer addresses different aspects of security, creating a more robust overall system.

The inclusion of firewalls, intrusion detection systems, and anti-virus software aligns with common practices in layered defense strategies. Firewalls provide a barrier to unauthorized access and help control traffic based on predetermined security rules. Intrusion detection systems monitor network traffic for suspicious activities and can alert administrators to potential threats. Anti-virus software protects systems by detecting and removing malware, which is crucial in preventing and mitigating attacks.

File encryption, while an important security measure, primarily addresses the confidentiality of data at rest or in transit rather than acting as a defensive layer against attacks. It prevents unauthorized access to the actual content of files but does not inherently stop threats from exploiting the system or breaching networks. Therefore, file encryption does not fit within the typical components of a layered defense strategy, which is primarily focused on actively repelling and detecting security threats.