Some potential new legal precedence is being set by a federal judge in Vermont, after ruling that data shared via peer-to-peer file-sharing services should not be expected to be private.

The ruling came out of a case regarding child pornography, where the defendants attempted to have evidence dismissed based on the grounds in which it was obtained. The three defendants said that police scooped the pertinent data from a peer-to-peer network illegally, without a warrant.

In this case, law enforcement had made use of the Child Protection System, which is an assortment of software tools designed to track down child pornography online. The tools send out automated searches for files known to contain data of this kind, and then maps out matching files with an IP address, data and time, as well as various other details about the particular computer.

District Court Judge Christina Reiss denied the motion to have the scraped data be dismissed, saying that the defendants gave up any privacy they had by making the files available through the P2P service. Even though the police software was entirely automated, Reiss says that the data could have been obtained manually or by a member of the public just the same.

"The evidence overwhelmingly demonstrates that the only information accessed was made publicly available by the IP address or the software it was using," Judge Reiss explains. "Accordingly, either intentionally or inadvertently, through the use of peer-to-peer file-sharing software, Defendants exposed to the public the information they now claim was private."