preferTrust: An ordered preferences-based trust model in peer-to-peer networks

• We define a peer's service ability in more detail with n-dimensional trust vector.
• We quantify a peer's qualitative preference and calculate its expectation with AHP.
• We adjust the evaluation vector on the basis of the user's expectations.

Aiming at solving the two problems in existing trust models, rough trust description and simplistic trust decision, an ordered preferences-based trust model, preferTrust, is proposed for peer-to-peer networks. First, we define a service as an n-dimensional attribute vector in order to reflect the service provider's abilities in different attributes in detail. Second, considering the fact that different peers may have different preferences for each attribute of a service, which are usually represented in the qualitative expressions, such as better, worse and so on, we transform those peer's qualitative preferences to the quantitative ordered preferences with the method of analytical hierarchy process (AHP), and based on which to calculate the requester's expectation vector. Finally, we combine the requester's expectation vector with each responder's trust vector to calculate an estimate value for each responder which will help the requester make the final trust decision. The simulation results show that preferTrust is able to both improve the trust decision satisfaction and resist malicious attacks effectively and efficiently.