A federal judge in Vermont has ruled that there should be no expectation of privacy for data shared across peer-to-peer file-sharing services. In a case centered around the detection of child pornography, three defendants argued that information gained from a P2P network had been illegally obtained by police without a search warrant. Police officers had used a number of software tools, known collectively as Child Protection System, to create automated searches for files known to contain images of child pornography. The system automatically matches files with an IP address, hash value, date and time, and other details of the computer involved.

While the defendants sought to suppress the evidence, District Court Judge Christina Reiss denied the motion and ruled that the defendants had given up privacy by making the files available through the P2P network. "The evidence overwhelmingly demonstrates that the only information accessed was made publicly available by the IP address or the software it was using," Reiss says. "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." While the software police used was automated, Reiss notes that the searches could have been executed manually by law enforcement officers or members of the public.