More than 23,000 U.S. Internet users could soon be notified by their internet service providers (ISPs) that their personal information is being turned over to the U.S. Copyright Group in the largest file sharing lawsuit in U.S. history.

Wired reported that a federal judge has agreed to allow the copyright enforcement agency to subpoena ISPs to obtain the identity behind the 23,000 Internet protocol (IP) addresses that allegedly downloaded the 2010 film The Expendables using the file sharing software BitTorrent.

BitTorrent is a popular peer-to-peer (P2P) communications protocol for file sharing that excels at transferring large amounts of data. It is used for both legal and illegal file transfers.

The IP addresses of alleged copyright infringes can be easily obtained by companies that snoop on active torrents and record the IP of peers who are downloading and uploading files. Hoping to evade copyright enforcement agencies, file sharers have created software such as PeerBlock to block IP's associated with the companies. But the software, which relies on large lists of IP address maintained by volunteers, does not guarantee safety from copyright lawsuits.

The U.S. Copyright Group is expected to threaten to sue anyone that allegedly downloaded the film and offer a settlement in the range of $1,000 to $3,000. The company has previously sued thousands of downloaders of the films Steam Experiment, Far Cry, Uncross the Stars, Gray Man and Call of the Wild 3D.

A lawsuit filed against the U.S. Copyright Group in November 2010 claimed they had made a business of threatening people with expensive litigation and fines.

"It is well beyond time that the courts take control of these automated enterprises being run at great taxpayer expense with the active assistance of the federal court system," Lory Lybeck, a Washington state attorney defending BitTorrent users, said.