Definition and Defending Against a Bump Key

Using a ‘bump key’, or lock bumping, is a lock picking technique used to open a pin tumbler lock. One bump key will work for all locks that are of the same type. A bump key will work on all locks of the same keywave which means that a bump key that works on a Schlage lock will work on all Schlage locks with the same amount of pins or less.

If you look at a bump key you will notice that cuts are jagged like teeth. Applying pressure to the key while tapping it allows for a split-second that the top pins are above the sheer-line and the bottom pins are below it thus allowing the cylinder to turn.

How to defend against bump keys:

  • Replace your current locks to high-security locks like Medeco, Mul-T-Lock and Schlage Primus for example.
  • Replace your locks to electronic locks, magnetic locks, or locks using rotating disks which are not vulnerable to this attack.. These provide better security and are easy to recode. The customer has to ability to recode these locks himself most of the time.
  • A bump key must have the same blank profile as the lock it is made to open. Restricted or registered key profiles are safer from bumping because the correct key blanks cannot legally be obtained without permission or registration with relevant locksmith associations.
  • Install an alarm system. Even though this will not cancel the susceptibility of your locks to key bumping, our experience finds that alarm systems provides a good deterrent to the everyday burglar.
  • Locks that contain trap pins engage when a pin that does not support them will jam in the lock’s cylinder.
  • Shallow drilling, in which one or more of the pin stacks is drilled slightly shallower than the others, is another method of prevention. If an attempt were made on a lock that has shallow drilled pin stacks, the bump key will be unable to bump the shallow drilled pins because they are too high for the bump key to engage.