Defense in depth

Defense in depth is a way of trying to make it more difficult for someone to break into a system. It involves using different layers of security. For example, if someone is trying to break into a building, the first layer might be a door that needs a key to open it. The second layer might be a password for an alarm system that needs to be entered to get in. The third layer might be cameras that watch the area. By having multiple layers like this, it makes it much harder for someone to break in.