Dynamic trust model for reliable transactions in multi-agent systems

Most network applications such as pervasive computing, grid computing, P2P etc. can be viewed as multi-agent systems which are open, anonymous and dynamic in nature. Due to such nature multi-agent systems present potential threats in ensuring secured communication. One of the key feasible ways to minimize threats is to evaluate the trust and reputation of the interacting agents. Many trust models have done so, but they fail to properly evaluate trust when malicious agents behave in an unpredictable way. Not only that they are also ineffective in providing quick response to a malicious agent's oscillating behavior i.e., they are unable to assess the true nature of an opportunistic agent. To cope with such strategically altering behavior this paper presents a dynamic trust model where we analyze the different factors related to the trust of an agent and then propose a comprehensive mathematical model for evaluating trust. Simulations show that our model compared to other existing models can effectively cope with the strategic behavioral change of an agent and at the same time efficiently isolate the malicious agents.