Defense in Depth (DiD)
Defense in Depth (DiD) is a cybersecurity strategy that employs multiple layers of security controls (physical, technical, and administrative) throughout an IT system. This approach is designed to provide redundancy in the event that one security layer fails or is bypassed. The concept is based on a military strategy that aims to delay rather than prevent the advance of an attacker by making it more difficult for an adversary to breach a system. In the context of IT security, DiD involves the implementation of diverse defensive mechanisms such as firewalls, intrusion detection systems (IDS), intrusion prevention systems (IPS), antivirus software, encryption, access controls, and security policies. The goal of DiD is to protect the integrity, confidentiality, and availability of information by creating a multi-layered security infrastructure that makes it significantly more challenging for threats to penetrate and compromise an enterprise network.