Key-Switch Flaws

From The Mind of Gabriel Shear

Tuesday, July 1 2014


Why You Shouldn’t Use Key-Switches

KeyswitchI come across this type of setup quite often.

You’ve got an electronic access control system installed.Worried that one day your system might not work you decide you need key overrides (This defeats some main points of using electronic access control) While usually on doors that use electric latches, or in handle solenoid release mechanisms a normal keyed door handle to unlock the handle in an emergency is the norm. On the other hand, doors that use magnetic locks or other means not related to the normal method of opening a door require a different approach. Enter the key switch.

Like its name implies, this device contains a key cylinder and an electrical switch. When a key is inserted into the lock and rotated, a cam on the rear of the cylinder depresses a switch which is normally used to break power to magnetic locks or signal the access control system to release the lock. Regardless of the way in which it controls the door it still boils down to the fact that A KEY IS USED TO RELEASE THE LOCK!

Looking at the photo above you will probably notice to very immediate things. First the key-switch is easily accessible and second, it is attached using the very insecure security screws. If someone were to remove those two screws. This is what they would see on the other side of the key switch.Keyswitch backA switch mechanism which can easily be bypassed with one finger… One little finger!


Seriously, this is all that is required to bypass this high-end access control system. While not a fault in the system itself, this situation has none the less been created. Granted not all key-switches have this exact design. Some have the switch built into the cylinder. Still the purpose of the switch is to make or break an electrical circuit, and whether or not it has an exposed switch is beside the point. As long as the wires are exposed you can either open the circuit (cut the wire) or close it (short the wires together).

There are a few ways in which you can increase the security of key-switches.

Possible solutions:

Move the key overrides to a more central and secure location.

Install a local siren with a sensor (plunger or magnetic reed type) installed on the key-switch so as to draw attention if the device is removed. (Alarm must latch to on state once set off to be affective)

If using security guards. Monitoring of the access control system for alarms is an option.

Email notifications from the access control system are possible if available and responded to in a timely manner.

Generally in this setup the switch just disengages the locking mechanism but doesn’t inform the access control system that it has done so. Once the door is opened the system will set an alarm condition. Depending on the system and the response programmed, it may only log that information or set off a linked burglar alarm or local siren. It is usually the case that, do to the high number of alarm conditions triggered by normal everyday use, that not much is done to alert anyone of the alarms do to the nuisance factor. People generally are not very security conscious and convenience usually triumphs.

If you use, or are planning to install such a system, you have been warned! Criminals have this information and know the flaws!

– Gabriel Shear