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Bump Keying


This article is borrowed with permission from Red Deer College's Locksmith Apprenticeship Program web page. For more information about Alberta's Locksmith Apprenticeship Program, see


"Bump Keying" is a technique for defeating a standard pin tumbler lock cylinder using a specially-fashioned key and a small hammer or mallet. To the Locksmith, it falls under the category of "cute tricks" and is not a technique that is often used, since it offers no advantage over conventional lock picking.


The basic technique of bump-keying

The basic technique of bump keying


By "Standard Pin Tumbler Cylinder" we mean the lock cylinder that is used by almost all residential locks and 80-90% of commercial locks. "Cylinder" is the component of a lock which accepts the key.


Lock cylinder removed from a typical deadlock assembly

Lock cylinder removed from a typical deadlock assembly


Regrettably, the technique has received a great deal of publicity over the past few years and has developed into something of a "sensation". The sensation began with a group of individuals based in Holland who engage in "lock picking for sport". They learned of the technique and garnered a great deal of publicity for themselves by exposing it to the news media under the guise of moral outrage over the vulnerability of today's locks, and concern over the public's right to know about the threat. This has resulted in a number of reactions:


1) A flood of bump key "How To" videos on internet sites such as Youtube, Metacafe, Google etc.


2) News media "special investigative reports" that serve to publicize the idea and inform viewers/readers about all the "How To" videos available on the internet. The vast majority of these "crime alerts" can also be viewed on the internet.


3) Bump keys being made for sale and sold through (where else?) the internet. The internet even offers a way of ensuring a vendor's ad for bump keys appears on the same web page as the crime alerts and "How To" videos mentioned above.


4) Lock products being advertised as "Bump Key Proof" by Locksmiths, Distributors and Lock manufacturers.


5) Misconceptions about how to guard against bump keying, mainly due to items 2 and 4 above.


The misconceptions include: 

  • A lock cylinder can be made significantly less susceptible to bump keying by simply rekeying it to a "more appropriate" code. In fact, this will have only a minimal effect on the bump key resistance of a cylinder.
  • A lock cylinder can be made significantly less susceptible to bump keying by rekeying it using special tumblers. There are special tumblers designed to increase pick resistance, but use of these will also have only a minimal effect on a cylinder's bump key resistance.
  • Spraying WD-40 in your locks will "loosen the tumblers and make bump keying more difficult". This has no basis in fact. Lubrication such as WD-40 or dry powdered graphite (never both) sprayed sparingly into the keyway, will help your lock cylinder work smoothly with less wear, but will have no effect on its "bumpability", with the possible exception that it may make the cylinder slightly easier to bump key.
  • Any lock that doesn't use a key, is more secure because it cannot be bump keyed. In fact, electronic locks and mechanical keyless locks all have their own vulnerabilities. They're simply not as well-televised at the moment.
  • Bump keying leaves no detectable evidence behind. In fact, bump keying leaves tool marks on a lock cylinder that can be detected under a microscope by a trained eye. Just as in the case of lock picking, normal use of the lock after the event can obscure the evidence. It is also true in both cases that only a lock picking or bump keying attempt can be detected. It cannot be determined from tool marks, whether or not an attempt was successful.
  • Expensive locks are even easier to bump key than cheap locks. This claim is made in comparing lower priced and higher priced standard pin tumbler cylinders, without considering high security lock cylinders. In other words, the "expensive" locks referred to, are not high security locks.
  • There's no way to guard against bump keying. In actual fact, the "Lock pickers for sport" neglect to mention the significant number of key/lock mechanisms that they have not been able to bump key.


How to guard against the threat of bump keying? Quite simply, high security lock cylinders. Or, more accurately, almost any lock cylinder that is more complex than the standard pin tumbler cylinder. There are many high security cylinders on the market. The photo below shows a small sampling.


Selection of High Security Cylinders

Selection of High Security Cylinders


As you can see, most of them outwardly appear very similar to the standard pin tumbler cylinder. Many are variations on the basic pin tumbler design; with a secondary locking mechanism incorporated. The majority are also designed to retro-fit pin tumbler cylinders in exisiting lock hardware and come in a wide variety of cylinder styles to fit key-in-knob locks, cylindrical deadlocks, mortise locks, rim locks, just to name a few. Not all residential locks can be retro-fitted, but many can.


Deadlock with high security cylinder installed

Deadlock with high security cylinder installed


There are also many products on the market that don't meet the Security Industry's strict definition of a High Security cylinder, but are still quite effective against bump keying.


To a Locksmith, carrying a brand of high security lock cylinder usually involves a significant financial committment. For this reason, most Locksmiths select one or two brands to sell and no one Locksmith will be able to offer you all of the brands that are available.


For More Information


Press releases on the topic of the bump key sensation can be found at:

Professional Locksmiths Association of Alberta (PLAA)

Associated Locksmiths of America (ALOA)

ALOA's "Bump Key Press Room" contains links to many news stories.


Following is some information that will help you to research high security locks on the internet.


Assa Abloy Group:

Here you'll find links for:

    • Assa
    • Abloy
    • Medeco
    • Mul-T-Lock
    • Sargent (High Security Products include Keso F1, Assa V-10, Signature, XC Series)
    • Corbin/Russwin (Their high security cylinder is called "Emhart")

Scorpion CX-5:



(High security products include Everest, Primus, and Everest Primus)



Professional Locksmiths Association of Alberta
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