The four basic layers of physical security are design, control, detection, and identification. For each of these layers, there are different options that can be utilized for security. Physical security design refers to any structure that can be built or installed to deter, impede, or stop an attack from occurring. Limiting the number of building entrances, channeling movement through the building to go through security checkpoints with security officers or locking devices, are all part of the physical security design of a building. Video surveillance is considered an essential layer of physical security and can be monitored live by security officers for suspicious activity or recorded to be reviewed at a later time. Physical security controls refer to all control capabilities in a building, from mechanical and electronic to procedural, that limit access to certain areas.
