3D printed bump keys make short work of high-security locks

High-end locks rely on their unique key-shapes to prevent "bumping" (opening a lock by inserting a key-blank and hitting it with a hammer, causing the pins to fly up), but you can make a template for a bump key by photographing the keyhole and modelling it in software.

Jos Weyers and Christian Holler presented their work on 3D printed bump keys at NYC's Hackers on Planet Earth last month, as an existence proof of the insufficiency of relying on proprietary shapes to defend a lock. The locks they attacked were successfully opened with keys printed in nylon, of the sort you can order from service bureaux like I.Materialize and Shapeways. Weyers and Holler have produced an app called "Photobump" that turns images of keyholes into print-ready 3D bump-key shapefiles.

A photo of a keyhole alone isn't quite enough to print one of Weyers' or Holler's bump keys. They also need information about the position of each pin in a target lock. But Holler says that information easily is found in widely available key-cutting software. Weyers says he can derive it even more easily by sticking any thin tool into the keyhole, feeling for the pins, and marking their depth to measure how deep in the lock's cylinder the pins are located…

Weyers and Holler aren't trying to teach thieves and spies a new trick for breaking into high-security facilities; instead, they want to warn lockmakers about the possibility of 3-D printable bump keys so they might defend against it. Although Holler will discuss the technique at the Lockcon lockpicking conference in Sneek, the Netherlands, next month, he doesn't plan to release the Photobump software publicly. He's also working with police in his native Germany to analyze whether printed bump keys leave any forensic evidence behind.

These 3-D Printed Skeleton Keys Can Pick High-Security Locks in Seconds [Andy Greenberg/Wired]