While media companies step up their legal crackdown on Internet song-swappers, separate teams of software developers -- from the Middle East to Madrid -- are toiling away on a foiling technology: an a

While media companies step up their legal crackdown on Internet song-swappers, separate teams of software developers -- from the Middle East to Madrid -- are toiling away on a foiling technology: an anonymous file-sharing network.

"Our users are requesting more and more privacy. They are more than disgusted with the threat of lawsuits," says Pablo Soto, chief programmer and co-founder of Madrid-based Optisoft.

Optisoft runs music-only file-sharing networks Blubster and Piolet on its proprietary MP2P peer-to-peer platform.

The RIAA has sued 11 of MP2P's 10 million users for putting their music collections online for others to download. A new upgrade, which goes into effect shortly, should shield MP2P users from future lawsuits, Soto says.

"I do not think it will stop the RIAA from suing our users. But if any of our users has the balls to go to court, I don't see any way on the planet for the RIAA to win," Soto says.

The trade group, however, recommends taking any claims of anonymity with a grain of salt. "More often than not, these are marketing ploys rather than a genuine technological capability," an RIAA spokesman says.

Since January, the RIAA has sued more than 2,000 Americans for copyright infringement for sharing their music collections with others over Internet peer-to-peer networks such as Kazaa and WinMX.

Hundreds more face legal action in Europe and Canada, as trade groups there announce plans for similar lawsuits. Media companies have employed firms to scour file-sharing networks to find the biggest uploaders.

Soto says his new file-sharing network offers two layers of camouflage. Each user is assigned multiple Internet protocol (IP) addresses to mask precisely who is trading what file at what time. The files on the network are similarly disguised to look generic to the outside observer.

"With the files, you get a user ID and some data, but that data looks bogus," Soto says.

The multiple IP addresses, he explained, are pulled from other users on the network at the same time, thus distorting the activities of individual file sharers.

There is a serious flaw, Soto admits. Light users, who at the moment are not being targeted in the lawsuits, could be rounded up alongside other MP2P users who share hundreds or thousands of music tracks through the network.

But, he reckons, MP2P makes it four times more difficult for a copyright holder to trace the activities of file-sharers.

Elsewhere, Palestine-based EarthStation 5 uses third-party proxies' computers in an attempt to throw copyright lawyers off the trail. Another service, Filetopia, has developed encryption tools to protect the identity of its users and their actions.

The results of their combined work are far from foolproof, technology observers point out. "In theory, you can never have a completely anonymous network. But you can make it really, really difficult to trace," says Jupiter Research analyst Mark Mulligan.

--Reuters