FEW OF US would care if our house keys appeared in a photograph of the family picnic posted on the internet.
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But we should be concerned because advances in digital imaging and optics meant any photograph of a key posed a potential security threat, Stefan Savage, a computer science professor at the University of California, warns.
Professor Savage and two of his PhD students have developed a software program called Sneakey that can clone a key in "two to three minutes" after analysing a digital photograph.
The algorithm is so sophisticated it easily copes with the low-resolution mobile phone images routinely posted on social networking sites such as MySpace and Facebook.
"The software looks at the key, adjusts the image for any rotations or distortions, then produces a string of numbers that is appropriate for that key," Professor Savage said.
"Those numbers are fed into a key-cutting machine and it makes a perfect copy.
Professor Savage, 39, said his team at the University's Jacobs School of Engineering in San Diego found "thousands" of images of keys inadvertently posted on the photo-sharing site Flickr.
They also used a camera fitted with a telephoto lens to photograph and duplicate a set of keys on a cafe table from a distance of more than 60 metres.
Far from being unique, the bumps and valleys on a conventional key can be "completely described" using a five- or six-digit number, he said.
"The design of the keys we use today is 150 years old and the world has changed."
As a result, Professor Savage believes we should protect our keys in the same way we protect the code to our debit card.
Sneakey runs on an ordinary personal computer and uses key-cutting hardware that is readily available in Australia.
The University of California team is keeping the code secret, but Professor Savage admits anyone with a basic knowledge of programming and computer vision techniques would be able to reproduce it.
He believes the "keyless" locking systems used on modern cars will eventually become the standard for all security applications. Until then, you might think twice before posing for a happy snap with your keys dangling from your belt.
