At Defcon in 2005, an eleven year old girl named Jennalynn gave an eye popping demonstration of how easily she could bump open any lock presented. She showed off her talent by lock bumping an M3 high security lock from Medeco. The company claims that this lock is unbumpable.
Lock bumping, also known as “key bumping” and “bump keying” involves a technique in which an ordinary key can be modified with a file so that when it is inserted into a common door lock and tapped, the internal cylinder pins will bump up and the door lock can open. Most common household locks are vulnerable to this manner of picking.
It is thought that the history of lock bumping goes back to Danish locksmiths in 1970. The story goes that they were looking for a faster way to open locks and they developed this method. The public first became aware of the trick in 2005 when an European news program revealed how to use a bump key.
The method of bumping a lock has spread all over the Internet and on many local news stations, showing everyone how easy it is to bypass certain types of locks. These videos and reports are causing great concern for everyone from stay-at-home moms to business owners. Homemade bump keys are a new threat to the security of conventional mechanical locks because they are so quick and easy to make.
The basic premise of lock bumping exploits a flaw with modern pin tumbler lock designs. It enough force is applied to the lower pins in a lock, some of it will get transferred to the upper pin deck which pushes the spring up and makes a small gap between the pins for a fraction of a second.
So, because of this, lock bumping is a serious problem. But many critics just say all you need to do is replace your existing locks with a new Medeco or Schlage type lock that has a better design. Well, young Jennalynn shows that this too is creating a false sense of security because she can open these new locks.
So what can you do to protect your home and family from being a victim of lock bumping? Easy options are installing the very best new locks you can afford. They might be hard enough to bump that they will scare away an amateur. Other options include installing motion sensitive outdoor lighting and a home security alarm. Professional thieves look for easy targets and if you do all of that, there is a good chance they will go elsewhere.