During the summer of 2007, a rash of mysterious burglaries occurred in the Dallas, Texas area.  Residents of upscale apartment complexes would return home at the end of the day to find their doors unlocked and their apartments robbed.  Even more puzzling, the thieves were able to hit a dozen or more apartments in one day!  How did they do this?

Detective Scott Peterson was the one to finally solve the crime, discovering that the thieves, later known as the "Bump Key Bandits," were employing lock bumping, a technique often used by locksmiths to open doors.

A locksmith in Denmark first developed the technique of lock bumping.  At first, the method was to insert a key and apply a slight pressure while tapping on it with a hammer or screwdriver.  The force caused the tumblers in the key's cylinder to jiggle and sometimes open up.  Sometime around 2002, a simple tool called a "bump key" was developed to make the process easier.  Bump keys are not illegal, and can easily be purchased on the internet.  In fact, most commercial and residential locksmiths keep bump keys in their arsenal of tools for opening locked doors.

In 2005 Barry Wels and Rop Gonggrijp of the Dutch organization TOOOL (The Open Organization of Lockpickers) drafted a paper detailing the method and application of lock bumping.  This technique finally attracted a great deal of attention in 2005 following the broadcast of a Dutch television show.  The show detailed the risk of illegal entry and potential for theft by using lock bumping techniques.

Around the same time, an American security expert, Marc Tobia, began to publicly discuss the technique and its serious security risks.  This information began to circulate through the media, and criminals in the United States and other countries quickly took note.  Now there are numerous online resources for anyone wanting to learn how to bump locks.  Kits for making bump keys are readily available to anyone with a credit card, and thus the technique of lock bumping has become a major security risk to the general public.

So how do you protect yourself and your family?  Ironically, many high quality locks on the market today only make lock bumping easier.  Very expensive locksets are manufactured with precise tolerances in the key cylinder.  Because the pins work so smoothly, lock bumping becomes much easier.  Furthermore, locks made of hardened steel are even more vulnerable because they are less prone to damage during the bumping process, whereas a cheaper lock is more likely to jam and not open.

Locks with security pins (for example, spool or mushroom pins) combined with a regular tumbler mechanism generally make lock bumping more difficult.  Electronic locks, magnetic locks, and locks using rotating disks are even better options because they can rarely if ever be opened via lock bumping.  Another option is a type of lock featuring "trap pins."  The pins in these locks' key cylinders are designed to jamb when someone tries to bump the lock.

Many companies now sell "bump proof" or "bump resistant" locks; however, bear in mind that as of yet, there is still no official standard as to what constitutes a "bump proof" lock.  For absolute security, look for locks that don't have a slot for a key, such as touchpad locksets requiring you to enter a combination to open the door.  After all, a thief can't enter your home with a bump key if there's no place to insert it!

Apartment dwellers remain the most vulnerable to lock bumping attacks.  Because most apartment locks can all be opened by one master key, they are extremely easy to bump, thus the reason why the Dallas thieves targeted only apartment complexes.  If you do rent an apartment, insist that the locks be changed before you move in, so that prior residents cannot enter your home.  If your landlord refuses to change the locks, inquire if you can replace them on your own.  If all else fails, choose a safety prop or some other device to prevent unauthorized entry.