A reactive approach for detection of collusion attacks in P2P trust and reputation systems

Internet today is also a medium of sharing immeasurable amount of information for widespread Peer to Peer (P2P) environments. Various application domains such as file sharing, distributed computing and e community based applications adopted the P2P technology as underlying network structure. A fairly open structure of P2P network applications, also make peers exposed. Interaction with unfamiliar peer in the absence of a trusted third party makes them vulnerable to potential attacks. To enable a reliable communication among peers, trust and reputation mechanisms came into existence. Malicious behavior of peer itself within the network, make reputation system themselves as vulnerable to attacks. Malicious peers often collude to procure a collective objective. The paper reviews existing collusion attacks. It also proposes a reactive defense mechanism against such collusion attacks. The proposed mechanism, detects collusion based on underlying trust and reputation knowledge. It also provides a reduction mechanism to chastise colluded peers.