Peer-to-peer (P2P) networking is a distributed system of file sharing where any PC on the network can see any other PC on the network. Users access each others’ hard drives to download files. This type of file sharing is valuable, but it brings up copyright issues for music, movies, and other shared media files. Users are also vulnerable to viruses, Trojans, and spyware hiding in files. Also see: Trojan horse, spyware.