A system analysis of reputation-base defences against pollution attacks in P2P streaming

In recent years, the demand for multimedia streaming is soaring over the Internet. Due to the lack of a centralized administrative point, Peer-to-Peer (P2P) streaming system is vulnerable to pollution attacks, in which video segments might be altered by any peer before being shared. Among existing proposals, reputation-based defence mechanisms are the most effective and practical solutions. In this paper, we perform a measurement study on the effectiveness of this class of solutions. We implement a framework that allows us to simulate different variations of the reputation rating systems, from the global approach to the decentralized local approach, under different parameter settings and pollution models. In order to ensure the framework and the simulated solution is representative enough, we dissect existing proposals and implement a flexible defence mechanism, in which different components may be enabled and disabled by simply tuning certain parameters. Our results reveal that global knowledge of the content flow in the network does not necessarily improve the performance. It is often susceptible under collaborative attacks. We also find that expelling misbehaving peers is often more useful to prevent attacks than limiting their likelihood to be connected, although this can lead to poor playback quality.