What is Lock Bumping?
Many locks contain a cylinder with a pin tumbler mechanism. These cylinders have a set of pins, often five or six in a row. Each set of pins actually contains three parts: a lower pin, an upper pin, and a little spring. The lower pins have different lengths and sit in the barrel part of the cylinder (the plug) and make contact with the key. The upper pins sit above these and run from the plug into the cylinder body and prevent the plug from turning. When the correct key is inserted into the lock each pin is pushed up exactly the correct distance so that the join between each lower pin and upper pin lines up along the sheer line between the cylinder plug and body. This enables the plug to turn and activates the lock.

Lock bumping exploits a fundamental weakness in the design of the pin tumbler locking mechanism. Physics dictate that if you apply enough kinetic energy to the lower pin this will be transferred to the upper pin which will push up on the spring and create a gap between the two pins for a split second. If this gap falls across the sheer line between the plug and cylinder body in each pin chamber, the plug will turn. This is the theory behind lock bumping, but how do you achieve this pin separation effect?

The technique is startlingly simple. All you need is a special key called a bump key and a hitting tool like the handle of a screwdriver. A bump key is a key which has been cut down to the deepest cut at each pin position. Any key that will fit into the lock can be filed down to create a bump key.

The bump key is inserted into the lock and withdrawn a bit. Turning pressure is placed on the bump key with one hand and hit into the lock with the back of a screwdriver (or similar object) with the other. Sometimes a few hits are required until the pins are correctly "bumped", the pins separate for a split second, the plug turns, and the lock opens.

This describes basic lock bumping. There are other techniques and tools available but the principle remains the same.

Am I at risk from lock bumping?
Many homes, offices and business in the United Kingdom are at risk from lock bumping.

Lock bumping is technique whereby certain locks can be opened with a specially prepared "bump" key and any suitable hitting tool. This technique has been around for some years but started receiving more peoples attention through the internet and media reports from 2005.

Lock bumping is a real risk to physical security that needs to be addressed for several reasons:

The number of locks at risk: Most locks containing a pin tumbler mechanism can be bumped. Many doors, gates, security barriers etc. only have this type of lock fitted rendering them vulnerable. Even so called "high security" locks could be vulnerable. The problem is a fundamental weakeness to the design of the cylinder. The strongest, most drill resistant, snap resistant lock could still be bumped. In fact some "experts" report high quality locks made from good materials are the easiest to bump. Many famous, household name lock brands have faced the indignity of having videos of their locks being bumped posted on the internet. Many rim locks contain rim cylinders that can be bumped. Also there are many locks that are operated with Euro or Oval profile cylinders that are at risk. These cylinders are found not only in door locks but in a wide range of physical security products. Many uPVC doors are fitted with these cylinders:

Media / internet exposure of lock bumping: If your reading this article you've heard of lock bumping. There is now lots of information on the internet and articles on how to make a bump key and techniques for bumping a lock. The information is free and easy to find. It is very simple for any criminally minded individual to add bump keys to his tool kit.

Sadly a bump key can be created for the cost of a key blank and a file and you can even use the back of the file as your hitting tool. The technique can be easily self taught and does not require any special skills. Compared to lock picking and other methods of bypassing locks, bumping is not technically challenging and much quicker to master.

Little evidence of intrusion: The lock should not be damaged when bumped, so it is very difficult to prove the lock has been bypassed. Some insurers require evidence of a break-in or some use of force to gain entrance to the property in the advent of a burglary, so insurance claims may be rejected.

Can I buy a bump proof lock?
Yes. Lock bumping is technique whereby certain locks can be opened with a specially prepared "bump" key and a suitable hitting tool. Only certain locks can be bumped. Most locks that rely only on a pin tumbler mechanism can be bumped. Many cylinders in rim locks and uPVC doors have pin tumblers. Fortunately it is quite easy to protect yourself from bumping.

The easiest way to protect yourself is to use a lock that does not use a pin tumbler. Most mortice locks use levers and do not use pins on springs so are bump proof by design. It is recommended to use British Standard Mortice Deadlocks. You can check if your mortice lock is British Standard by looking for the Kitemark.

Many rim locks are vulnerable to bumping because they use pin tumblers. Some however use a different mechanism, like the Chubb 4L67E British Standard Rim Deadbolt. This lock uses discs instead of pins and so cannot be bumped.

Some locks that utilise pin tumblers also contain additional security elements such as a sidebar. These elements may significantly reduce the risk of bumping, as although the pin tumblers can be bumped the sidebar would frustrate or prevent a bumping attack.

There are a few very secure cylinders that don't make use of pin tumblers at all. For example the Evva 3KS cylinder uses sliders and sidebars with no springs so can be considered bump proof by design.

It may be possible to upgrade the cylinder in your lock to one that is very hard or virtually impossible to bump. Many cylinders found in door locks are fairly easy to remove and replace and can be done on a DIY basis:.

uPVC Doors: Many Euro profile cylinders found on uPVC doors are vulnerable to bumping and should be upgraded. Often this cylinder is the only lock controlling all the bolts on the door so it is very important it is secure. There is a single screw on the edge of the door that retains the cylinder that needs to be removed. Then the key needs be inserted and turned a quarter turn to align the cam and the cylinder can be pulled out the door.

Rim Locks: Most rim locks have a common rim cylinder on the outside of the door that can be easily upgraded. The outside cylinder can be remove by removing the lock and undoing the two screws which hold it in place. Some rim locks also have a cylinder on the inside. These are often built into a handle and are not easily upgraded.

Pickbuster
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