'Master keyed' is when a group of locks are "custom" coded so each lock uses a different key, but a combination is "added" so one key will open all locks. It is a myth that there exists a particular Master Key that will open all locks. In order to Master-key a group of locks the locks must all be made by the same manufacturer or at least have "common" Keyways. In a group of locks that are Master-keyed (MK) each lock is operable by both it's own individual key and the Master-Key. Each individual key operates it's own lock only. The Master-Key operates all the locks in the group. Other systems are also possible using sub-Masters, Grand-Masters, etc. 'Keyed alike' simple means a group of locks will have one key that operates them all.
In order to prevent lock bumping to be a threat to your security you should call us today about high security locks. Criminals can get through most low cost, low security locks with or without the use of a "bumping" technique. In most cases however when a potential burgerlar sees a Mul-T-Lock, Medeco or Schlage Primus lock on a door, they move on.
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The threat
In a recent research paper, we describe weaknesses in most master-keyed lock systems, such as those used by offices, schools, and businesses as well as by some residential facilities (particularly apartment complexes, dormitories, and condominiums). These weaknesses allow anyone with access to the key to a single lock to create easily the "master" key that opens every lock in the entire system. Creating such a key requires little skill, leaves behind no evidence, and does not entail engaging in recognizably suspicious behavior. The only materials required are a metal file and a small number of blank keys, which for many locks are readily available.
Needless to say, the ability for any keyholder to obtain system-wide access represents a serious potential threat to the security of master keyed installations. Individuals and institutions that depend on such locks to protect their safety and property should be aware of these risks and consider alternatives to eliminate or reduce their exposure to this threat.
Who is vulnerable?
A master keyed lock system is one in which locks are designed not only to be opened by their individual keys, but also by special "master" keys that open some or all other locks in the system. They are commonly found in commercial, industrial, educational and government facilities as well as in some centrally managed residences. Master keying is used because it allows those who must have access to many locks (maintenance workers, managers, etc.) to carry only a few keys. (Note that master keying is unrelated to whether the locks are sold under the "Master ®" brand name.) It is not usually possible to tell by inspecting a key or a lock from the outside whether it is part of a master system. Individuals should ask their locksmith, building management, or maintenance office whether their locks are master keyed.
This research demonstrates that virtually all master keyed mechanical lock systems are at least theoretically vulnerable; the practical seriousness of the threat to any particular system depends on a number of factors:
Only master keyed locks are vulnerable to this threat. These techniques are not effective against locks that are not part of a master system.
In order to make a master key, the attacker must have access to one of the locks in the system and possess or have previously examined its associated key. Any lock and key in the system is sufficient for this purpose, and so any individual who has ever been given access to any key has the potential to carry out the attack. The technique involves a series of simple "probes" of a lock (typically less than fifty) which reveal successively more information about the master key. This can be done in several sessions; continuous access to the lock for an extended period of time is not required.
The procedure consumes a small number (less than ten) of "blank" keys of the kind that fit the locks. Blank keys for most commonly-used locks are available in small quantities from a wide range of commercial sources. The keys are "cut" using hand-held machines or a small metal file.
Alternatives and countermeasures:
Here in LVH SYSTEMS Locksmith We recommend
Mul-T-Lock is a world leader in the design and manufacture of Master Key systems to suit your security needs,
Medeco:The top level key (perhaps the business owner's key) is often referred to as the Grand Master Key and is able to open all the doors of a business security.
Schlage Key Systems: Restricted Key System - A restricted key system is a key system and corresponding key blanks whose sale is limited by its distribution. Note that a restricted key system is not necessarily a patented key system. Examples of Schlage restricted key systems are Quad key sections.
Patented Restricted Key System - A patented restricted key system is protected by legally enforceable patent protection from "look alike" key blanks and cylinders being manufactured and sold into the market. Example of Schlage patented restricted key systems are Everest D, Everest B and Primus XP. Note that not all patented restricted key systems are high security or UL437 listed. Schlage offers all types of patented restricted key systems according to the customer's needs.
Patented Open Key System - A patented key system where the sales of keys and components are not restricted in any way.
End User Keyways - Keyways and related products that are sold to end users for their exclusive use. End user keyways are not available for resale and are not used by commercial locksmiths.
Schlage Primus:
Primus Cylinder - Primus is a patented sidebar cylinder and key designed for key control, pick resistance and attack resistance. Primus is Schlage's highest security cylinder and is available in two families of keyways, Classic and Everest.
Side-bit Milling - A secondary milling on the key into the keyway that can have multiple unique patterns and operate through a corresponding secondary set of pins (finger pins) within the cylinder.
Primus Finger Pin - A unique L-shaped pin that needs to be swiveled and raised by the corresponding side-bit milling for operation of the lock.
Everest - One of Schlage's keyways with a patented undercut groove. It is available as full size and SFIC cylinders.
Classic Primus - One of Schlage's Classic keyways cylinder that contains the Primus locking mechanism as a secondary locking feature.
Primus Everest - An Everest cylinder that contains the Primus locking mechanism as a secondary locking feature.
Side Bar - A secondary locking device in a cylinder.
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Unfortunately, at this time there is no simple or completely effective countermeasure that prevents exploitation of this vulnerability short of replacing a master keyed system with a non-mastered one. Residential facilities and safety-critical or high-value environments are strongly urged to consider whether the risks of master keying outweigh the convenience benefits in light of this vulnerability. Lock users should evaluate these risks before purchasing or installing new master keyed systems.
Depending on individual circumstances, a range of defenses may be appropriate:
Eliminate the use of master keying entirely. This is the safest option in most cases. Simple mechanisms such as locked key control cabinets can provide a workable alternative to master keying, especially in smaller-scale environments.
Use a lock design that is not vulnerable. There are lock designs (including those that use "master rings," those that employ multiple cylinders, and those based on electronic controls) that permit master keying without this vulnerability, but they are not widely used commercially and may not be available for some lock applications.
Use a lock system for which it is difficult to procure keys. Some locks, particularly those marketed for larger-scale commercial installations, use "restricted" keys, which may make it more difficult for a potential attacker to obtain the correct blanks. However, in practice this may offer only the appearance of protection; many "restricted" blanks are in fact readily available from aftermarket and offshore sources, and even when they are not it is often not difficult to fabricate a working blank directly.
If master keying must be used, limit the scope of a successful attack by separating different functions into different master systems. For example, instead of having a single master system for an entire organization, use separate master systems for different work groups, floors, etc.
Call LVH SYSTEMS Locksmith for high security locks Installation 1-877-364-5264
