LOS ANGELES, Oct. 30 (Xinhua) -- U.S. computer scientists have built a software program that can make key duplications without having the key, a press release said Thursday.

    Instead, the computer scientists only need a photograph of the key to make duplications, said the release issued by the University of California in San Diego (UCSD).

    "We built our key duplication software system to show people that their keys are not inherently secret," Stefan Savage, a computer science professor from the UCSD's Jacobs School of Engineering, said in the release.

    "Perhaps this was once a reasonable assumption, but advances in digital imaging and optics have made it easy to duplicate someone's keys from a distance without even noticing them," said Savage, who led the student-run project.

    The bumps and valleys on a house or office keys represent a numeric code that completely describes how to open your particular lock. If a key doesn't encode this precise "bitting code," then it won't open the door, the release said.

    In one demonstration of the new software system, the computer scientists took pictures of common residential house keys with a cell phone camera, fed the image into their software which then produced the information needed to create identical copies.

    In another example, they used a five inch telephoto lens to capture images from the roof of a campus building and duplicate keys sitting on a cafe table about 200 feet away.

    "This idea should come as little surprise to locksmiths or lock vendors," said Savage.

    "There are experts who have been able to copy keys by hand from high-resolution photographs for some time. However, we argue that the threat has turned a corner -- cheap image sensors have made digital cameras pervasive and basic computer vision techniques can automatically extract a key's information without requiring any expertise."

    However, Savage said the idea that one's keys are sensitive visual information is not widely appreciated in the general public.

    As for what to do about the key duplication threat, Savage said that companies are actively developing and marketing new locking systems that encode electromagnetic secrets as well as a physical code.

    He suggested people treat their keys like they treat their credit card and "keep it in your pocket unless you need to use them."