A Trust Model With Forgiveness Mechanism In Social P2P System

Trust management can help peers in distributed netwoks to search and locate credible peers and resources,obtain services with high quality,and isolate malicious attacks effectively.However,traditional trust and reputation systems put more attention on how to make the system more effective,usable,and robust,but they ignored how to repair the attacks,which is more necessary in cases of good peers make mistakes occasionally.Besides,how to achieve a balanced workload among resource providers is another important issue to be solved.Based on the analysis above,this paper proposes a reputation system named ForgiveTrust with forgiveness mechanism for social P2 P environment.The forgiveness mechanism helps reputation systems to repair the trust break-down caused by unexpected errors.The basic assumption is: when an error occurs,the file uploader and downloader can overcome the harm of the error by forgiving the uploader.However,an abuse of forgiveness may cause the system very vulnerable.Because the real malicious behaviors would also be forgiven if there were no distinguishment between unexpected offences and malicious attacks.This paper incorporates several forgiveness motivations to deal with this issue.In ForgiveTrust,a peer can obtain the desired service very fast by utilizing personalized social links.And the malicious peers can be isolated by the dynamic penalty mechanism.To deal with the issue of load balance,this paper proposes a novel resource seletion algorithm based on the friend list in the social networks.The algorithm allows peers to select the service providers from his friends and follow the low workload first rule.Therefore,ForgiveTrust can isolate malicious peers and help peers obtain credible service theoretically.Besides,it can repair the trust break-down caused by occational errors between two good peers.Moreover,it achives a better workload balance.This paper further conducts vast of trace-driven simulations,which show the effectiveness of the proposed model.Particularly,ForgiveTrust can repair the trust break-down caused by the errors among good peers.Compared with EigenTrust,EigenTrust++,and PersonalTrust,ForgiveTrust shows its superiority in resisting malicious attacks,namely isolated,collection,camouflage and spy attacks.Furthermore,the experiments show a higher successful transaction rate and a better load balance in the network than the existing methods.