Probabilistic analysis of trust based decision making in hostile environments

Abstract

Trust and reputation systems are one of the most important tools for decision making which are able to predict the reliability of an agent, taking into account the past experience and received recommendations. However, the effectiveness of these systems may be greatly reduced in hostile environments with the presence of malicious attackers. Despite the increasing use of these systems and the importance of their robustness in hostile environments, So far the most efforts on reinforcing of these systems have been focused on trust computation models, not on the trust based decision making. This paper discusses the importance and impact of decision-making on the robustness of trust systems in hostile environments and shows its great impact in this regard. In the paper, the most important trust based decision-making methods are investigated using formal verification methods in different attack scenarios (including maliciousness and selfishness) and the results are analyzed to find the strengths and weaknesses of each one. Considering the obtained results, the paper also proposed a new approach for trust-based decision making. The case studies show that the proposed approach is able to improve the robustness of trust and reputation models in all different attack scenarios.