Security is the degree of protection to safeguard property or persons against danger, damage, loss, harm, and crime. Security as a form of protection are structures and processes that provide or improve security as a condition...".
The Perception of security may be different from actual security. For example, the fear of earthquakes has been reported to be more common than the fear of slipping on the bathroom floor although the latter kills many more people than the former. Or for example, two computer security programs could be interfering with each other and even cancelling each other's effect, while the owner believes s/he is getting double the protection.
Perception of security can also increase actual security when it affects or deters malicious behavior. Such items as with visual signs, guards, video surveillance, alarm systems in a home, or an anti-theft system in a car such as a GPS system or warning sign are examples. Some intruders will decide not to attempt to break into such areas or vehicles, there can actually be less damage to windows in addition to protection of valuable objects inside. Without such advertisement, a thief might approach a car, break the window, and then flee in response to an alarm being triggered. Either way, perhaps the car itself and the objects inside aren't stolen, but with perceived security even the windows of the car have a lower chance of being damaged.
However, the non-profit, security research group, ISECOM, has determined that such signs may actually increase the violence, daring, and desperation of an intruder. This claim shows that perceived security works mostly on the provider and is not security at all. It is important, however, for signs advertising security not to give clues as to how to subvert that security. A home burglar might be more likely to break into a certain home if he or she is able to learn beforehand which company makes its security system.
There is an immense literature on the analysis and categorization of security. Part of the reason for this is that the "weakest link in the chain" is the most important. The situation is asymmetric since the 'defender' must cover all points of attack while the attacker need only identify a single weak point upon which to concentrate.
Physical security describes measures that are designed to deny access to unauthorized personnel (including attackers or even accidental intruders) from physically accessing a building, facility, resource, or stored information. Physical security can be as simple as a locked door. It can be as elaborate as multiple layers of barriers, armed security guards or guardhouse placement.
Security inevitably incurs costs and can never be perfect or complete. But not all aspects of Physical Security need be high tech. Alert Animals (dogs, geese), the buddy system, hiding the resources, or hiding the fact that resources are valuable, is a good idea as it will reduce crime. Even something as simple as a thick or thorny bush can add a layer of physical security to a residential setting. Security can reduce but cannot entirely eliminate risks.
Strong physical security applies the appropriate combinations of overlapping and complementary controls and are generally intended to:
- deter potential intruders (warning signs and perimeter markings);
- delay, frustrate and ideally prevent intrusion attempts (obstacles, strong walls, door locks and safes);
- detect intrusions and monitor/record intruders (lighting, alarms, siren and cameras);
- distinguish authorized from unauthorized people (using pass words/cards/badges/duress codes and keys) and
- respond to repel, catch or frustrate attackers (by owner, guards and police).
Physical security is also not a modern phenomenon. The technology is continually evolving along with the threats. Physical security controls that were considered adequate in the past tend to be insecure today due to advances in the knowledge and capabilities of attackers. In the same way, controls that currently appear strong are likely to prove vulnerable in future, in ways that may not be obvious right now.