X2BT Trusted Reputation System: A Robust Mechanism for P2P Networks

Over the past few years, Peer-to-Peer (P2P) networks have grown extensively and dramatically changed large-scale file transfer. One of the most popular P2P network is the

BitTorrent

system. BitTorrent can efficiently distribute large files by optimizing the use of network bandwidth and providing scalability. Due to the open and anonymous nature of P2P systems BitTorrent also provides an ideal environment for distribution of malicious, low quality, or doctored information. A number of reputation systems, including

P2PRep

with its successors

XRep

and

X

2

Rep

, had been proposed to address security weaknesses of Gnutella P2P file sharing networks. Although it has been claimed that these methods are also applicable to the other file sharing networks, it is not clear how to achieve this task. Moreover, some of the shortcomings of these reputation systems such as online-polling only and cold-start may be exploited by malicious attackers. In this paper, we propose a reputation system, called

X

2BT

Rep

, which is an extension of the

X

2

Rep

and for BitTorrent network. We show that the proposed system improves the security and the quality of information distributed over P2P networks.