Chinese Journal of Computers   Full Text
Title	DyTrust: A Time-Frame Based Dynamic Trust Model for P2P Systems
Authors	CHANG Jun-Sheng WANG Huai-Min YIN Gang
Address	(School of Computer, National University of Defense Technology, Changsha 410073)
Year	2006
Issue	No.8(1301—1307)
Abstract &   Background	Abstract An important challenge regarding peer’s trust valuation in P2P systems is how to cope with strategically altering behaviors and dishonest feedbacks of malicious peers efficiently. However, the trust models employed by the existing systems do not provide adequate support to coping with quick changes in peers’ behavior and aggregating feedback information, so the authors present a time-frame based dynamic trust model DyTrust. After incorporating time dimension using time-frame, which captures experience and recommendation’s time-sensitivity, the authors also introduce four trust parameters in computing trustworthiness of peers, namely, short time trust, long time trust, misusing trust accumulation and feedback credibility. Together, these parameters are adjusted in time to reflect the dynamics of the trust environment using feedback control mechanism, thus, the trust evaluation has better adaptability to the dynamics of trust. Theoretical analysis and simulation show that DyTrust has advantages in modeling dynamic trust relationship and aggregating feedback information over the existing trust metrics. It is highly effective in countering malicious peers regarding strategic altering behavior and dishonest feedbacks of malicious peers. keywords peer to peer; feedback; dynamic trust model background This research is supported by the National Basic Research Program(973 Program) of China under grand No.2005CB321800; National Natural Science Foundation of China under grant No.90412011; National High Technology Research and Development Program (863 Program) of China under grant Nos.2003AA115210, 2003AA115410, 2005AA112030. P2P(Peer-to-Peer) technology has been widely used in file-sharing applications, distributed computing, e-market and information management. The open and dynamic nature of the peer-to-peer networks is both beneficial and harmful to the working of the system. Problems such as free-riders and malicious users could lead to serious problems in the correct and useful functioning of the system. Reputation-based trust management systems can successfully minimize the potential damages to a system by computing the trustworthiness of a certain peer from that peer’s behavior history. The research group presents a time-frame based dynamic trust model called DyTrust, which has advantages in modeling dynamic trust relationship and aggregating feedback information over the existing trust metrics. It is highly effective in countering malicious peers regarding strategic altering behavior and dishonest feedbacks of malicious peers.