Defense in Depth

Why Have A Mote?


Because it’s romantic?  A mote gives a great story plot?  Nope, a mote helps see, hear and may be stop a bad thing from happening?

Bodiam Castle showing walkway over the moat. East Sussex England.

There were motes around property, cities and castles.  A mote may stop, dissuade and detection a threat wanting to enter.  Today, the “Mote” concept is in ever present but generally less obtrusive.

That one may swim or paddle a boat across a mote demonstrates security measure limitations.  Security experts, realists and castle builders know, there exists no magical defense that would protect all assets from every threat. Most every security measure that exists has a countermeasure. That is why one should never rely on a single measure to protect our assets. We should design a multi-layer physical protection system by combining security measures.

Deep Security or Defense in Depth is the cornerstone of physical security. Defense in Depth involves different security layers, each with different but complimenting capabilities. These layer capabilities are generally defined in four areas:

Deter – Prevent the attack

Detect – Be aware that an attack is in progress

Delay –  Slow the attack and buy time for an appropriate response

Defend – Take action to counter the attack


Capabilities and solutions: 

Deterrence, detection, delay, and defense each have tools we can deploy.  Let’s examine several tools and apply these to our Defense in Depth.


Barriers:  Primary capability is deterrence and the secondary capability delay

Deterrence requires limits. These limits can be psychological or physical. In physical security these are called limit barriers. Psychological barriers are a product of communication. They can be signs (DANGER Do NOT Enter), symbols (police badge), or the result of indoctrination. Good

deterrents induce a fear of danger.

Physical barriers can be fences, walls, hedges, rivers, cliffs, safe boxes, or even a squad of riot police. Good physical barriers also provide a delay capability.

The best barriers are both psychological and physical, they can prevent and delay attacks.

We use barriers to set up perimeters around the assets we want to protect. Most often we do this with fences or walls. We will need at least two perimeters. An outer perimeter and an inner perimeter.  We usually allow at least one point of entry/exit inside a perimeter, typically a gate or door, that becomes a part of the barrier.


Alarm systems:  Primary capability is detection and Secondary capability is deterrence


When deterrence is not enough and our perimeter has been breached, we want to be notified as soon as possible.  Alarm systems are comprised of two parts, a sensor and an alert mechanism.

Sensors may monitor movement, heat, sound, pressure, vibration, and a lot more. Advances in technology give us new kinds of sensors such as: cameras with motion detection, optical fiber sensible to pressure, glass break sensors.

The alert mechanism could be a siren, an email, a phone call, a database record, a panic button, any mechanism letting you know that an event has happened. Some alarm systems can be set to call your nearest police station when a sensor (or more) is triggered.

Alarms systems can give a deterrence capability and in some cases, delay as well. In order for the physical protection system to be effective, the alarm system must alert someone (or something) that is able to assess the situation and take appropriate action. Otherwise it is useless for protection (but can aid investigation).


Access controls:  Primary capability is to delay and secondary capability: Deterrence / Detect


Delaying is just that, slowing and retarding optimal progress.  This is frequently accomplished by multiple parameters, such as a fence and building wall.

Causing an aggressor further delay may involve access controls and access points, entry/exit, of perimeters. They allow or deny passage.  Access control examples: The lock on your front door, a card reader at the gate of a fenced parking, a police officer asking for ID to enter a crime scene, the combination of a safe box, a biometric scanner inside a nuclear facility.

Access points are most often the weakest point of a barrier (it is easier to go through a door than a wall). Automated perimeter access control may be done by using keys, access cards, passwords, combinations, biometrics.  These same tools may be used for information security.

In case of forced entry, the access control mechanism should resist and buy time in order to allow a response before the asset is damaged or lost.


Security Force(s):  The primary capability is defending and secondary is deter, detect or delay.


Security force is intended to respond to the attack and prevent damage or loss of the asset. The goal of the responder is to stop the progression of the attack, by limiting the liberty of movement of the attacker, destroying its will and/or capabilities. Finally, the attacker can be apprehended if the situation permits.

Once the incident is resolved, its handling should be documented and later reviewed. In civilized countries, citizens and corporations can call the police to respond to illegal attacks threatening their assets.

Private security force can be employed when no police can be called or to have a better response time, bigger force, specific response, etc.

Depending on location, hour, events and size of your security force, it takes time for it to respond. That is why it is important to know the reaction time of your security force when implementing delay measures.


About THOR Feed & ThroughPoint Solutions, Inc.

THOR Feed® is a risk mitigation and inventory software available in Android®, iOS® and Windows® applications.   THOR Feed is wholly owned by ThroughPoint’ Solutions, Inc.  Our team and system  taps into over 27 years’ experience helping people identify and mitigate risk and build trust.  ThroughPoint Solutions is based in Gilbert, AZ and was founded in 2014.

If you would like more information about this topic, please contact Jim Watkinson at ThroughPoint Solutions or email at

*Android is a registered trademark of Google Inc., Apple is a registered trademark of Apple Inc. and Windows is a registered trademark of Microsoft Inc., THOR Feed® is a trademark of ThroughPoint Solutions, Inc.

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