Now one group of researchers has released a piece of software that makes copying purportedly uncopyable keys easier than ever. 

On Tuesday, a group of University of Michigan researchers released a new web-based tool that lets users 3-D print any of thousands of "restricted" keys designed to defy copying attempts. Aside from the "do not duplicate" warnings on restricted keys, lock makers also try to prevent their duplication by using contorted keyways—the space inside a lock that a key's inserted into—and selling the blanks that fit them only to users who can prove their affiliation with a big client like a corporation, university, or government agency.

But the researchers' tool, which they've called Keysforge, is meant to demonstrate that those obscure key shapes no longer offer the security they did before accessible 3-D printing. With little more than the restricted key and a photo of the front of the lock, Keysforge can produce a CAD file ready to 3-D print a working key on any consumer-grade 3-D printer. "We've proven that restricted keyways are no longer a defense," says Michigan researcher Ben Burgess. "We've shown that anyone with a 3-D printer can quickly and easily attack these systems."