A new evidential trust model for open distributed systems

Trust model plays an important role in ensuring the security of interactions in open distributed systems where entity’s trust evaluation depends on interaction experience of its own and recommendation information from other entities. However, current available trust models have limitations in solving not only the issues of time efficiency of direct interaction information, but also the reliability and inconsistency of recommendation information. In this paper, an improved D–S evidence theory is given by introducing a time efficiency factor calculation function, multi-layer evidences reasoning and an improved fusion approach for conflict evidence. Furthermore, a new trust model for open distributed systems, namely extended D–S theory based trust model (ExDSTM), is presented, which solves some problems such as the declining in performance of the trust model without considering the timeliness, reliability and incompatibility of evidence. Theoretical analysis and simulation results show that ExDSTM has advantages in modeling dynamic trust relationship and aggregating feedback information compared with some other trust models, so that it is highly effective in defending attacks on the system for malicious behaviors.