Tech

A technique for cracking computer passwords using inexpensive off-the-shelf computer graphics hardware is causing a stir in the computer security community.

Elcomsoft, a software company based in Moscow, Russia, has filed a US patent for the technique. It takes advantage of the "massively parallel processing" capabilities of a graphics processing unit (GPU) - the processor normally used to produce realistic graphics for video games.

Using an $800 graphics card from nVidia called the GeForce 8800 Ultra, Elcomsoft increased the speed of its password cracking by a factor of 25, according to the company's CEO, Vladimir Katalov.

The toughest passwords, including those used to log in to a Windows Vista computer, would normally take months of continuous computer processing time to crack using a computer's central processing unit (CPU). By harnessing a $150 GPU - less powerful than the nVidia 8800 card - Elcomsoft says they can cracked in just three to five days. Less complex passwords can be retrieved in minutes, rather than hours or days.

It is the way a GPU processes data that provides the speed increase. NVidia spokesman Andrew Humber describes the process using the analogy of searching for words in a book. "A [normal computer processor] would read the book, starting at page 1 and finishing at page 500," he says. "A GPU would take the book, tear it into a 100,000 pieces, and read all of those pieces at the same time."

Benjamin Jun, of Cryptography Research based in San Francisco, US, says massively parallel processing is ideally suited to the task of breaking passwords. And, while concerned about the development, Jun also pays tribute to the achievement: "A number of us have been following advances in those platforms, and there's a lot of elegant, intelligent design."

Password cracking can be used to unlock data on a computer, but will not usually work on a banking or commercial website. This is because is takes too long to run through multiple passwords, and because a site will normally block a user after several failed attempts.

Jun adds that the trend towards encrypting whole hard drives with increasingly long cryptographic keys still means it is becoming more difficult to access sensitive data. "Should I throw away my web server and run for the hills?" he says. "I don't think so."

NVidia released a software development kit for its graphics hardware in February 2007. Known as CUDA, the kit lets programmers access the computing power of the GPU directly. It has gained a following among those with a need for high-performance computing, particularly in fields such as science and engineering.

"[CUDA] is a huge thing for the oil and gas industry, for the financial sector, and for scientists," Humber says. He adds that CUDA is also be being used by a company called Evolved Machines to simulate the way the human brain wires itself.

Elcomsoft says it took three months to develop code to take advantage of a GPU, and the company plans to introduce the feature into some of its password cracking products over time.

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