The film industry and a hacker publication will head back into court Tuesday in the DeCSS case, a legal dispute that could dictate whether it's legal to publish or link to certain materials online. A panel of appellate judges will decide whether to uphold a lower court ruling preventing online hacker magazine 2600 from linking to code that theoretically could be used to crack DVD security. But legal experts say the case could have wide-ranging ramifications for linking, publishing and copyright on the Internet. "The courts have to craft a ruling that tells people when they may or may not publish certain content," said UCLA law professor and computer scientist Eugene Volokh. The case also is the first major test of the Digital Millennium Copyright Act (DMCA), an entertainment industry-backed law designed to extend copyright protections into the Digital Age. The legal dispute began in January 2000, when the Motion Picture Association of America sued 2600 and several other Web sites for publishing and linking to DeCSS code, claiming that it violated their copyrights. DeCSS was originally designed to let programmers create a DVD player for Linux machines -- technology that did not exist at the time -- but the movie industry argued that it eventually could be used to copy DVDs. Other sites named in the suit caved and removed the code, leaving 2600 and its publisher as the only defendants in the case. After a lively trial featuring teen hackers, computer scientists and record executives, New York Federal District judge Lewis Kaplan sided with the MPAA, ruling that 2600 could neither post nor link to the code. The Electronic Frontier Foundation (EFF), which is representing 2600, appealed the ruling in January 2001, calling it a blow to the First Amendment. The case has attracted a wide variety of participants, including the NFL; the American Society of Composers, Authors and Publishers; and the Screen Actors Guild, which have filed amicus briefs urging the appeals court to uphold the ruling or risk rampant spreading of pirated works on the Web. In addition, the Justice Department jumped into the case in February, arguing that Kaplan had properly enforced the DMCA and saying the suit is "really about computer hackers and the tools of digital piracy". On the other side are computer scientists, journalists and librarians, who have filed briefs calling Kaplan's ruling a severe threat to free speech. "The case gets very close to overstepping the boundaries of both academic freedom and freedom of speech," said MIT computer science professor Harold Abelson who, along with 16 other world-famous programmers, signed onto a brief in support of 2600's side. "Once you start saying that simply a computer program is a device that can be restricted or regulated, that runs smack against freedom of expression." During oral arguments Tuesday before the 2nd US Circuit Court of Appeals in New York, each side will get 20 minutes to present its views and answer questions from the panel. The EFF will speak first, then the MPAA and the Justice Department will split their 20 minutes. Courts have been divided over whether code is free speech. In the DeCSS case, Kaplan has ruled that it isn't. But in another case, a federal appeals court in California ruled that the National Security Agency's attempt to prevent professor Daniel Bernstein from posting encryption software was a restraint on freedom of expression. Another major issue in the case is the anti-circumvention clause of the DMCA, a tenet prohibiting possession of any device that could be used to circumvent copyrights. The MPAA is arguing that DeCSS is one such device. Abelson worries that an MPAA victory could inspire other copyright owners to push to broaden the definition of circumvention measures. "Anybody who has any software program at all that they want restricted can just call it a circumvention device," Abelson said. Just last week, the Secure Digital Music Initiative, an industry-backed group working to secure music, sent threatening letters to a group of professors who wanted to present a paper explaining how they cracked some digital watermarking code. SDMI told Princeton professor Edward Felten that he and his colleagues risked violating the DMCA if they gave the speech; the researchers backed down. MPAA attorneys already have said Kaplan's decision gives the entertainment industry extra muscle to go after those they think are violating copyrights. The ruling is "not aimed at speech", said Chuck Sims, a partner at law firm Proskauer Rose who's arguing the case for the MPAA, which represents major film companies such as Universal Studios, Warner Brothers, Metro-Goldwyn-Mayer, Walt Disney, Sony Pictures Entertainment, Paramount Pictures and 20th Century Fox Film. "The law doesn't tell anyone they can't speak," he added. "All the law says is that you can't distribute to the world a device for circumventing technology that protects copyright." In addition to copyright issues, the DeCSS case touches a broader dispute about linking. In its brief, a group of journalists argued that upholding the ruling, which prevents linking, could hinder "the basic functioning of the Web." UCLA professor Volokh, who is not involved in the case, said an appellate ruling upholding Kaplan's decision could have dire consequences for linking on the Web. "The logic of this decision is that it's OK to enjoin the publication of links if these links are going to help somebody break the law," he said. For example, taken to its extreme outside the realm of copyright, Volokh said the ruling could put reporters at risk if they write about online gambling and provide a link to gaming sites. "It could [close] the door to all other sorts of linking," he added. The MPAA's Sims said such worst-case scenarios are beyond the scope of this case. "The law doesn't say on its face that nobody can link," he said. "What's scary is the Chicken Little approach that the EFF and others share." Dan Burk, a University of Minnesota law professor who signed onto a brief in support of 2600's case, isn't optimistic the appeals court will overturn the ruling. "The court will try very hard to give the movie industry as much as they can, both because Congress wanted them to and because they stand to lose so much money." The trick for 2600, he said, "is to show them they shouldn't go too far". I want to visit the DVD Basement Have your say instantly, and see what others have said. Click on the TalkBack button and go to the ZDNet News forum. Let the editors know what you think in the Mailroom. And read what others have said.