Study on signatures of P2P protocols based on regular expressions

As P2P applications are evolving rapidly, application layer identification is an effective way to recognize different P2P protocols recently. In this paper, research and analysis of the six popular P2P applications in China, such as QQ, BitTorrent, PPLive and so on, are presented, signatures of which are found and described by regular expressions providing reference for identification and manipulation of P2P traffic from the point of content-based pattern matching.