Most residential locks vulnerable to “lock bumping”

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This article includes three videos from local television stations around the U.S.

The vast majority of residential door locks are susceptible to a technique known as lock bumping that can be used to quickly and easily unlock residential door locks. The mysterious disappearances of belongings from peoples’ homes is sometimes explained by this, since lock bumping gets a thief inside a home with no signs of a forced entry.

Bump keys

Lock bumping is achieved using a specially cut key called a “bump key”.

Bump Key
a typical bump key

While bump keys open pin-and-tumbler locks that have been in use for over 80 years, the use of bump keys is a recent phenomena, becoming popular within the past two or three years.

Earlier this year I was in an Infragard meeting that included a demonstration of bump keys. It is scary how easy they are to operate; with a minute of practice I was able to easily open residential locks. This is knowledge that I do not wish to have, but I feel uneasy knowing that common criminals are also learning about this.

Bump key setsEntire sets of bump keys that fit over 90% of residences are easily purchased from online sources, many of which are willing to sell to people who are not locksmiths. How-to videos are also readily available.

Laws still catching up

It is not universally illegal to own bump keys. Criminals may be able to escape prosecution on breaking-and-entering on the “I had a key” defense. When U.S. laws do catch up with this new phenomenon, many thousands of illegal bump key sets will be “out there” and homes will probably be vulnerable for decades to come.

Insurance and law enforcement

The use of bump keys as a means of entering a house is not universally known, which could lead to difficulties when dealing with insurance companies and law enforcement.

If someone robs your house and gained entry using a bump key, you may have trouble making an insurance claim. Insurance companies will suspect insurance fraud if you are trying to make a mysterious disappearance claim where there is no sign of breaking and entering.

Similarly, filing a police report for a bump-key related burglary may be problematic, as the police may wish to see evidence of forced entry.

Bump key countermeasures (things you can do to reduce the risk of bump-key enabled burglaries):

  • Electronic locks
  • Schlage Primus keyPets (which make noise when visitors approach)
  • Security systems
  • Bump-resistant locksets from Kaba (UK), Medeco, and Schlage Primus

If everyone were to run out and purchase bump-proof locksets or other countermeasures, home burglaries will not stop. Instead, burglars will return to other means for breaking into residences. But, I do not feel that people will be running down to their local home improvement stores and locksmiths for new locksets. Not in 2007 anyway.

More information

WMC-TV Memphis, Tennessee, USA news story on lock bumping:

Fox-19 Cincinnati, Ohio, USA news story on lock bumping:

12 thoughts on “Most residential locks vulnerable to “lock bumping”

  1. Conservatory TV

    I was interested in reading this article about lock bumping. In the UK, we suffer more from ‘lock snapping’ where burglars snap the cylinder in half using mould grips and then get through uPVC doors that way.

    But lock bumping is on the increase, probably due to the publicity in the US!

  2. Dewi

    Lock bumping is less of a problem here in the UK as we have very good lever mortice locks. The problem is people don’t always use them – relying on the slam shut night latch.

    Interesting blog. I’ll keep an eye on it.

  3. Karen

    Lock Jaw Security is the best affordable solution to prevent lock bumping of deadbolts. We feel much safer. My husband even broke the actual key testing it. Their website is

    [editor’s note: this can be effective but you have to be in the house, as it changes the deadbolt so that it cannot be unlocked even with a key]

  4. JWT

    This happened to my friend a few months ago. The insurance companies were reluctant to pay out because there was no sign of forced entry. We found a company called Antibump Locks that sells virtually bump proof locks online.

  5. Brenda

    Lock Jaw Security does what it was designed to do. Yes you are correct that you must be on the inside unless you exit out the garage door. They are changing the locks to make them harder, but what do you do with the one we already have in place. You are correct about the insurance companies also. They will pay but it takes time.

  6. Paul

    Lock Jaw is certainly a respectable product, but for a solution that covers both lock bumping and kick-ins check out the ultimate lock. It’s the strongest deadbolt door lock you’ll find.

  7. ACME Locksmith

    I am the owner of ACME Locksmith. Lock manufactures have released new locks with technology to prevent lock bumping. Most are simply a drop in replacement of the old lock and readily available. You can learn more about the new technology on our website’s Knowledge Center under Home Security.


    KEYPOUTTM is a privacy and anti lock bumping device. Lock bumping is a popular burglary technique. A bump key is inserted into the lock and with a few taps from a screwdriver, intruders have instant access to your home. This technique eliminates noise, forced entry and damage to your home. In a matter of seconds, an intruder can quickly and easily enter your home leaving you and your property vulnerable to theft. Bump keys are being sold on the internet that fit most manufacturer’s locks.

    KEYPOUT’sTM unique patented design prevents locks from being bumped. Slip the device over your deadbolt and the lock won’t turn! KEYPOUTTM is designed to fit most common deadbolts and its versatile design allows for various turn-knob positioning.
    KEYPOUTTM is ideal for renters, condo owners, college students, senior citizens, babysitters, kids home alone, single women and men, single moms and dads, travelers, or just about anyone. KEYPOUTTM makes a great gift.

    KEYPOUTTM is ideal for renters, condo owners, college students, senior citizens, babysitters, kids home alone, single women and men, single moms and dads, travelers, or just about anyone. KEYPOUTTM makes a great gift.

    Find it at:


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