A Novel Free-riding Prevention Technique Based on Secret Sharing in BitTorrent-like Peer-to-Peer Networks ∗

Collaboration is the key premise of Peer-to-Peer (P2P) systems because its success highly relies on the voluntary contribution of resources by individual peers. Selfish peers or free-riders who attempt to benefit from others ’ resources without sharing their own, however, cause system-wide performance degradation in P2P systems. To address this problem, much research has been done in this area, however existing works are not widely used due to either their complexity or inefficiency. In this paper, we introduce a simple but highly efficient free-rider prevention technique which forces a peer to cooperate based on (t, n) threshold secret sharing. Our simulation results show that free-riders take much more time to complete their download 1 compared to those of compliant peers, which means that it’s nearly impossible for peers to freely ride on the system without any contribution under the proposed framework. Another unique benefit of our framework is that the system can now provide fairness. Our experiment shows that there is a strong correlation between the upload rate and the download completion time of a peer.