Defense in Depth (DiD)
Defense in Depth (DiD) is an approach to cybersecurity in which a series of defensive mechanisms are layered in order to protect valuable data and information. If one mechanism fails, another steps up immediately to thwart an attack. This multi-layered approach with intentional redundancies increases the security of a system as a whole and addresses many different attack vectors. Defense in Depth is commonly refered to as the “castle approach” because it mirrors the layered defenses of a medieval castle. Before you can penetrate a castle you are faced with the moat, ramparts, draw-bridge, towers, battlements and so on.