These 3D-printed bump keys can pick any lock

| September 3, 2014

Your valuables may not be safe anymore—not even if you keep your key safe. German engineers Jos Weyers and Christian Holler have found a way of making skeleton keys without even seeing the original key.

3D-printed bump key

From Weyers

They’ve put a new spin on an old technique: bumping. Traditionally, lockpickers have bumped key blanks in a lock using a hammer to tap the key. This makes the key blank’s teeth bump against the lock cylinder’s pins. This in turn, makes the pins jump. If done in the right manner, the technique can successfully open a lock.

Till now, high-security lock manufacturers would patent their key blanks. They considered their restricted key shapes or profiles secure. Just a few verified clients could access them. They might have to rethink their strategy. “It’s a kind of false sense of security,” says Holler. “If a protected profile is your only protection, you should be aware that’s no longer enough.”

Weyers and Holler use a 3D printer and software called Photobump to make a 3D model of the key. The two only need a few easily available details about the lock. These include a photo of the keyway or pathway of the lock or the pins’ position on the key blank of the lock. “Basically, if I can see your keyhole, there’s an app for that,” says Weyers.

Even the cost of a 3D printer is no deterrent. You can order a skeleton key to be mailed to you via a 3D printing service like Shapeways or i.Materialise.


There’s no reason to be alarmed. Weyers and Holler merely want to warn locksmiths about their method. They have no intention of making their software available to the public. In fact, Holler is even working with the German police to see whether his technique leaves any forensic evidence.

Lock manufacturers aren’t too worried about the new threat. “The use of such keys depends on many variables and is not particularly reliable,” says Joachim Gillert, the research and security director of Assa Abloy, a lockmaker.

Perhaps the takeaway is “Lock manufacturers know how to make a lock bump-resistant. And they had better,” as Weyers points out.

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Category: security, Technology