Linear Iterations on Ordered Semirings for Trust Metric Computation and Attack Resiliency Evaluation

Within the realm of network security, we interpret the concept of trust as a relation among entities that participate in various protocols. Trust relations are based on evidence created by the previous interactions of entities within a protocol. In this work, we are focusing on the evaluation of trust evidence in Ad Hoc Networks. Because of the dynamic nature of Ad Hoc Networks, trust evidence may be uncertain and incomplete. Also, no pre-established infrastructure can be assumed. The evaluation process is modelled as a path problem on a directed graph, where nodes represent entities, and edges represent trust relations. We develop a novel formulation of trust computation as linear iterations on ordered semirings. Using the theory of semirings, we analyze several key problems on the performance of trust algorithms. We also analyze the resilience to attacks of the resulting schemes.