Master Key Exceptions

I have been building master key systems lately and mostly they have been simple tree structures.  There are times when you should vary from this. Some are statutory and some simply more practical. (I am not going to cite laws of my province or nation, since the net is bigger than that.  Get to know your local laws.)

A room or group of rooms should be outside the basic master key system if any of the following apply.

1. Cash storage or high value inventory.  If you ask staff to sign for the contents of a room or safe or till drawer, then you should isolate key access very strongly. If many staff travel about casually with keys, then cash or product shortages can not be traced.

2. Explosives. Lets keep these in the hands of only the licensed people.

3. Drugs. You may need to distinguish between OTC, prescription and narcotic type drugs. These are often treated differently in the laws which govern who has control for these.  Often the drug storage in a hostipal ward is under the control of only one pharmacist or a senior nurse.  Some drugs have street value and then during the day issues of armed robbery need be addressed and at night issues of forced entry need be addressed.

4. Forensic evidence. Police agencies collect objects which may have to later be used in court. However, accounting firms and others gather information which they may later pass to the police to generate charges.  For this to be useable in court, you need to show you have had continuous custody of the artifacts.  If not, the police can not lever your information into a search warrant and certainly not as evidence in court. Hence, private investigators need to have control of the keys to rooms holding records and artifacts.

5. Radioactive material. Workplace safety issues requires you keep untrained staff safely away from radiation.  Additionally, there are often federal regualation.

6. Personnel records. Employment records are best isolated from general access. Since you often have a janitor with a partial masterkey, this room will often get cleaned during the days. (Now that I get to it, many of the rooms above get cleaned during the day and often by the staff responsible and not the general janitorial staff.)

7. Accounting records in a server room. Your financial files are expected to be secured at the same level as paper records. The server room needs keying restricting it to only those who need access. (Regulations which derive from the Sarbanes–Oxley Act of 2002 in the USA may affect you and it is your responsibility to know it.)

8. Fire arms and munitions. Much like explosives and radioactive material, if you have these to store in a room, you know you have regulations governing their storage.

There are several ways to key rooms outside the master key system.  The worst is to simply pick a random key and pin the cylinder to that. Now you have to keep that as a record should you need to cut more keys. Often these rooms have very small sets of people with keys even having only ONE key in circulation which passes at shift change to the person on duty. If you pick a random key, you have to manually read through the pages of key records to assure there is no cross-over with any other room.

The better way is to plan for a small number of rooms to have master key exceptions and block them. All the keys are close together and the relationship to other key groups is clear.

These exceptions can be done in one of two ways.  The first is to have the key below the Top Master Key (TMK) with no intermediate master keys at all.  In a crisis, only the most senior staff can get access to the room. This might be how personnel records are kept. The other way is to set the lock as Single Key Different (SKD) with no master keys functioning at all. This is possibly better for drug and narcotic storage.

No list like this could be complete and the keys have to react to how the organization is structured. If you think I should add more categories, feel free to toss me a line.


And remember, keep your follower on the plug.

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Laux Myth ... Thoughts From a Locksmith
By MartinB, Found @ http://lauxmyth.blogspot.com/