File-swapping and instant messaging company Aimster has opened a new front in the online music wars, asking for court protection against the record industry in a pre-emptive legal strike. Aimster, one of the most high-profile file-trading services to launch in Napster's wake, on Monday asked a New York federal court for a "declaratory judgment" stating that its service doesn't violate US copyright law. Like several of its rivals, Aimster received a letter from the Recording Industry Association of America in the aftermath of court rulings against Napster, asking it to block trades of copyrighted music through its service. Now, the company is telling a court that it is primarily a service for private communications and that it should not be forced to dig into each subscriber message to determine whether it might contain copyrighted music. "We would have to eavesdrop on people when what we're guaranteeing is their privacy," said Johnny Deep, an Aimster spokesman. "It would be a totally inappropriate use of our" ability to unscramble messages. A spokesman for the RIAA confirmed that the group had sent Aimster the letter but declined to comment on the court action, saying that attorneys had not yet seen the lawsuit. The legal effort comes as Napster is losing its lustre under a court order requiring it filter out copyrighted works, a step that other file-swapping networks such as iMesh and Audio Galaxy are adopting voluntarily. The filing could bring to a new level the question: How much responsibility must file-trading companies have to monitor their networks? Aimster has consistently been testing copyright holders' grasp on copyright law, developing a service that is deliberately harder to track and harder to monitor than those from other file-trading companies such as Napster or iMesh. The company's software piggybacks on IM contacts, drawing "buddy lists" from programs such as AOL Time Warner's AOL Instant Messenger and Microsoft's MSN Messenger and then allowing people to swap files within that group. Because the files are available only to a small number of people, these short-lived private networks of buddies are hard to monitor. The company also is adding encryption technology that would scramble all messages or files that go between the software's users. Creating any kind of monitoring system that would break through this encryption to spy on Aimster members would itself be a violation of US copyright law, the company contended. Aimster's court action takes it a step further than other file-trading networks, most of which are cooperating with the RIAA. IMesh has posted a notice saying that it is working on a filtering system at the request of the RIAA. Copyrighted works are still widely available through that company's service, however. An Audio Galaxy staffer confirmed that the company, which has proven a popular alternative to Napster, is also blocking links to some songs. So far, Aimster has not added filtering mechanisms. The company's request for the court ruling, which is being handled by a lawyer at Napster attorney David Boies' law firm, was filed in federal court in Albany, New York. Another petition was filed by BuddyUSA, a software company that works with Aimster and was the recipient of the original RIAA letter. Aimster attorney George Carpinello declined to compare the company's case with the ongoing record industry suit against Napster. In that case, Napster has consistently lost its attempts to seek copyright law protection for its service. "Our position is that we are an ISP, and we comply with the safe harbor provisions" of copyright law, Carpinello said, referring to legislation that protects Internet service providers from liability for copyrighted content transferred through their networks. "The RIAA is trying to impose on us a duty to patrol and censor what goes through a private network." Take me to the MP3 Special Have your say instantly, and see what others have said. Click on the TalkBack button and go to the Napster Debate. Let the editors know what you think in the Mailroom. And read what others have said.