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Public Information about “Lock Bumping”

The El Segundo Police Department is advising the public about a technique thieves use to defeat locks that is known as “lock bumping” or “key bumping”. This technique is a way of opening many locks by using a specially filed key that is the same size and shape as the target lock. The “bump key” is inserted into the lock and then struck several times with an object. The impact of the strikes affects the lock’s tumblers allowing the thief to unlock the door. This technique allows a thief to open the majority of locks within seconds causing virtually no damage to the lock.

Information on this technique is widely available on the Internet. Ironically, higher-quality locks may be more vulnerable to bumping unless they are specifically designed to prevent this technique. Locks having security pins (spool or mushroom pins, etc.) when combined with a regular tumbler mechanism—generally make bumping somewhat more difficult.

Some countermeasures for reducing the likelihood of bumping include the purchasing of high security locks that are designed to prevent bumping. These locks have pins combined with a regular tumbler mechanism that will typically make bumping more difficult. Other locks that are electronic, magnetic or that incorporate rotating disks can not be compromised with the bumping technique. It is also advisable to purchase locks with restricted or registered key profiles because the correct key-blanks cannot be legally obtained without proper registration.

The El Segundo Police Department does not endorse any lock manufacturer but several companies claim to have bump proof locks and their links are listed below:








In addition to installing better locks, other tips to deter criminals from entering your house include:

  • Security alarm systems
  • Security lighting
  • Dogs
  • Securing doors and windows with special locks
  • Security landscaping

For further information or a FREE Home Security Survey, please contact Crime Prevention Officer Laurie Risk at (310) 524-2274.

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