Share-Ratio-Based Incentive Mechanism for File Sharing with BitTorrent Protocol

Abstract

Several P2P file-sharing networks were successfully deployed and are used by millions of Internet users globally to share files (such as movies, video clips, software systems, e-books, etc.) cooperatively over the Internet. These networks were designed with cooperation in mind, therefore, several incentive mechanisms were devised to encourage cooperation among downloaders and yet the free-riding phenomenon remains a threat to these networks since free-riders could indulge in acts such as whitewashing, Sybil, and collusion attacks to escape penalties imposed by the incentive mechanisms. This paper proposes a share-ratio-based incentive mechanism for P2P file-sharing networks where files are shared via BitTorrent protocol. The proposed incentive mechanism is not prone to Sybil and collusion attacks, and it was designed to simultaneously: (1) encourage cooperation, (2) provide fairness to new downloaders, and (3) deter free-riding while resisting whitewashing attack. The proposed incentive mechanism does not require any central entity to be realized and it was designed in existing terminologies used in P2P file-sharing networks, hence, it is easy to implement. In addition to the accomplishment of the set objectives, the proposed incentive mechanism has successfully deterred free-riding as shown by the experiments conducted.