Skeleton Keys Created Quickly and Easily with 3D Printing

Movies in which high-tech thieves use the tricks of their trade to gain unauthorized access to locked doors might soon show them holding skeleton keys made from slices of plastic. The advantages of any technology are equally available to all regardless of ethics. A 3D printer no more decides that it will agree to create prosthetic limbs for children than that it will be used to create firearms.

There are people for whom inaccessibility itself is something to always be challenged. In some cases this takes the form of urban exploration, in others computer hacking. In the case of Jos Weyers and Christian Holler the challenge of the lock is one that cannot be ignored.

Instead of using a coat hanger or a set of variable sized lock picks, the new trick is to 3D print a “bump” key. This can be done without ever laying eyes on the key design for the lock. Instead, this key can be inserted into the lock and given a bump on the head, hence its name, to open the lock.

So why aren’t Weyers and Holler sitting in a jail cell? Because they aren’t thieves, they are engineers, competitive lock pickers, and security consultants. Their efforts are directed not at teaching the art of breaking and entering, but rather to challenge complacent notions of what is secure. To this end, they have created a software called Photobump. With this software a bump key can be made for any lock if the user can provide a photo of the keyhole and the measurement of its depth.

For those who do not have a 3D printer, there is nothing to stop the creation of specialized bump keys to be shipped from 3D printing services such as Shapeways or i.Materialise.

Just as the introduction of 3D printing firearms has required an entirely new set of reactions, so does the bump key. It is not new and bumping has been performed before by filing key blanks into teeth to push against tumbler lock pins. What is new is the ease with which this type of key can now be produced for high-security locks. Previously, lock makers might have carefully guarded their key blank’s designs to prevent them from being distributed to those outside of the designated group.

For example, the Ikon SK6 uses careful contortion to make its blanks nearly impossible as targets for unauthorized reproduction. However, in a video released by Holler we can clearly see the effectiveness of the 3D printed and filed bump key that he has created.

It’s not quite as easy as it sounds however. To create some of the more highly sophisticated bump keys, you need more than just a picture of the keyhole. Information about the pin positions in a target lock is necessary to accurately shape the key. High-tech also has an answer here though: the Internet. Holler says that information is not hard to come by. Weyer’s finds that the pin position dilemma is answered by simply feeling them out and marking their depth.

No matter how the teeth on the bump key are derived, they can be fed into the software to create a 3D CAD model. Then, without knowing the make or manufacturer of the lock, the ultimate skeleton key can be created.

While 3D modeling programs and 3D printing machines do not have a sense of ethics, their operators most certainly do. Holler and Weyers do not plan to release their software publicly. In addition, Holler will be working with German police in an effort to determine if forensic evidence is produced when a bump key is used.

The maker of Ikon, Assa Abloy, was nonplussed by the bump key.

“We view this as an interesting exercise, but not particularly representative of the real world of covert entry by criminals and burglars. Yes, you can open some locks, some of the time with bump keys, even made with hard plastic. But… The use of such keys depends on many variables and is not particularly reliable.”

Whether or not this is a case of the Fox denying interest by calling the grapes sour, Holler and Weyers point out that this technology will only become easier to reproduce and more widely available.

“The sky isn’t falling, but the world changes and now people can make stuff. Lock manufacturers know how to make a lock bump-resistant. And they had better,” stated Weyers.

Let’s hear your thoughts on the fact that 3D printing can help thieves break through locks more easily, in the 3D printed skeleton key forum thread on 3DPB.com.