Bump Key
Even though the bump key (or lock bumping) concept has been around since the 1920s, it only recently came to the forefront of mass consciousness in the last few years as white papers and other documents were written by security experts on how easy it is to pick over 90% of home door locks in the U.S. by using a bump key.
A bump key is made by cutting all the teeth of a standard key as short as possible as well as cutting a piece out of the "shoulder" of the key, which is the part of the key that abuts the outside of the lock when the key is inserted. Once the bump key is inserted, it is bumped with a mallet or other object that transmits the force of the key pins to the driver pins inside the lock. This raises the pins up above the lock cylinder for a split second. If, during that split second, a rotational force is applied by turning the key, that split-second separation of the driver pins and the key pins is enough for the cylinder to turn and the lock to be opened. This is referred to as lock bumping and this method can be used to both open and lock a standard security door lock.
Bump keys work with conventional pin and tumbler door locks, which are extremely common. Creating, selling, distributing, or using bump keys is illegal in the U.S. under federal and some state laws, but that doesn't mean that it's rare. There are several internet sites where you can buy a bump key for around a nominal amount of money. This is a clearly preferable method of entry for most burglars (compared to crowbars or open windows) because it doesn't arouse as much (or any) suspicion. A person using a bump key can appear to be entering the house with the correct key. The fact that bump keys are illegal in the hands of non-certified locksmiths is cold comfort to the person whose locked home has been burglarized and has not done much to deter their use.
The scariest thing about bump keys is that, when they are used, there is no evidence of forced entry. This means that a burglar can easily bump open your lock, enter your home, steal your belongings and then leave without any trace of an actual “break-in”. Therefore it can be difficult or even impossible to receive any sort of reimbursement for your loss from your insurance company as they can argue that you either left your door unlocked or gave your key to the “wrong” kind of friend. With a standard security door lock on your door you are a vulnerable and easy target for someone using a bump key.
What can you do to protect your home? The easiest and most economical solution is to outfit your doors with high security door locks that protect against bumping and other types of lock picking. Manufacturers like Mul-T-Lock make high end, high security locks that include more complicated, layered locking mechanisms and utilize high security, dimple keys making it nearly impossible to gain entry via lock bumping, picking or even drilling. You could also consider electronic locks, magnetic locks, combination locks, or rotating disc locks.
