The Motion Picture Industry Association of America (MPAA) has won a round in its fight to keep its members' DVDs protected from unauthorized users.

US District Judge Lewis A Kaplan of the Southern District of New York granted a preliminary injunction, requested by MPAA members, to force three men to remove Internet postings that give the code for cracking DVD encryption.

The industry group demanded that the three New York-based defendants - Shawn Reimerdas, Eric Corley and Roman Kazan - remove the formula or face contempt of court charges.

The MPAA said the Digital Millennium Copyright Act of 1998 prohibits unauthorized use of such copyrighted materials.

"Judge Kaplan's ruling represents a great victory for creative artists, consumers and copyright owners everywhere," Jack Valenti, MPAA president and chief executive officer, said in a prepared statement. "I think this serves as a wake-up call to anyone who contemplates stealing intellectual property."

The plaintiffs in the injunction included Universal Studios, Paramount Pictures, Metro-Goldwyn-Mayer Studios, Tristar Pictures, Columbia Pictures Industries, Time Warner Entertainment, Disney Enterprises and Twentieth Century Fox Film.

The ruling is the latest action in the MPAA's attempt to keep its DVD videos protected from free access by the public. In recent months the MPAA has issued hundreds of cease-and-desist letters to Web site operators, telling them to stop posting the software.

"We feel that they are violating the law," Phuong Yokitis, an MPAA spokeswoman, said today.

A civil liberties group has criticized the ruling, saying the posting of the software is protected by free speech entitlement.

Tara Lemmey, executive director of the Electronic Frontier Foundation (EFF), said: "These cases are not about piracy or hacking. They are about censorship of free speech critical to science, education, and innovation."

The EFF is providing free legal representation to the defendants in the New York case and in a similar case in California. The judge's decision, the group said, could hamper the development of Linux and other open-source initiatives based on publicly-accessible and alterable software.

"If Judge Kaplan's reading of the Digital Millennium Copyright Act holds, then it will become illegal to build open-source products that can interoperate and/or compete with proprietary ones for displaying copyrighted content," John Gilmore, EFF co-founder, said.

The de-encryption formula, called DeCSS, was first posted on the Internet in October, 1998, and can de-encrypt movies or DVD disks normally scrambled by encryption code called CSS (content scrambling system).