How do the police trace people sharing illegal files on P2P?
People sharing copyrighted movies and music, as well as child porn and other illegal material through non anonymous peer to peer networks are doomed to be arrested. The police has a big collection of child porn files product of their raids, they hash those seized files (hashing means creating a unique digital fingerprint) then they insert the hashes into some law enforcement only peer to peer custom software they have, they hook it up to Kazaa, Gnutella, and other peer to peer networks. The police software searches for other files on the network that have the same hashing algorithm (digital fingerprint), if it matches it, then without even looking at the file the cops knows that user is sharing something illegal, now all they have to do is to log it, get the IP and apply for a warrant to search that person’s home. One way to thwart this system is by retouching that unique file, for example editing a picture with a photo editor and slightly increasing or decreasing the brightness would
