Improving robustness and fairness on BitTorrent-Like P2P systems

Recent studies have shown that BitTorrent, one of the most popular peer-to-peer file-sharing systems, is confronted with two serious problems: robustness and fairness. In this paper, a partially decentralized trust management system for BitTorrent is presented to deal with the two problems. By extending and modifying the functionality of the tracker in BitTorrent swarm, the extended tracker serves as an authoritative trust computation agent (TCA) to calculate and disseminate global trust values for all peers, which complement with local trust values to identify and isolate malicious and selfish peers. Simulations show that the proposed trust management system significantly decreases the impact of malicious peers on the swarm performance, and also achieves a much fairer block allocation among peers in heterogeneous scenarios.