Researchers crack computer code meant to protect online music files

A team of researchers from Princeton, Rice University and Xerox yesterday defended their claim that they cracked four security measures being tested to prevent illegal users from listening to copyrighted music.

The group of two University professors, three graduate students, two graduate school alumni and two colleagues at Rice responded to a challenge issued Sept. 6 by the Secure Digital Music Initiative — a consortium of more than 200 companies including Sony, Universal, Warner, BMG and EMI.

The SDMI — an organization with the goal of curbing piracy of digital music — created a contest on its Website challenging people to bypass four watermarking shields and two non-watermarking shields on downloadable music samples without damaging the original sound quality of the files.

Digital watermarks are hidden signals that are embedded in files and act as copyright marks for record companies.

With the Internet spawning MP3-distribution giants like Napster and recordable compact disc technology, record companies are scrambling to develop technology that would tighten security on their music.

The SDMI hopes to use the technology in digital music players that would deny access to any files without the correct watermarks.

Designers of the system hoped that if a hacker were to remove a watermark, the music quality would degrade.

But the researchers — who all had studied watermarking and computer security in the past — were able to penetrate the four walls without hurting the files' quality.

"We studied the technology to figure out how it worked and used signal processing to modify the music so that the hidden signals, the so-called 'watermarks,' were either removed or hidden," said Edward Felten, University computer science professor and spokesman for the group.

The other researchers in the group include University electrical engineering professor Bede Liu, Scott Craver GS, Patrick McGregor GS, Min Wu GS, Drew Dean GS '89, Dan Wallach GS '99 and two of Wallach's colleagues at Rice University.

There were 447 entries in the challenge that ended Oct. 8 and offered a $10,000 prize to successful groups. The Princeton group, however, is ineligible because it plans to publish its results — a disqualifying term in the contest rules.

Felten said he and the researchers were more interested in creating public dialogue by publishing the results than in receiving the money.

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"One, it was an interesting technical challenge," Felten said. "It's rare to get access to a state of the art commercial security system. Two, we feel it's an important topic for the future of the public and music users."

The SDMI will announce if there is a contest winner after its next meeting Nov. 8-10.