Self-Organizing Trust Model for Distributed System

Distributed networking technologies have gained popularity as a mechanism for users to share files without the need for centralized servers. A Distributed network provides a scalable and fault-tolerant mechanism to locate nodes anywhere on a network without maintaining a large amount of routing state. This allows for a variety of applications beyond simple file sharing. Examples include multicast systems, anonymous communications systems, and web caches. We survey security issues that occur in the underlying Distributed routing protocols, as well as fairness and trust issues that occur in file sharing and other Distributed applications.We discuss how techniques, ranging from cryptography, to random network probing, to economic incentives, can be used to address these problems. Open nature of Distributed systems exposes them to malicious activity. Building trust relationships among peers can mitigate attacks of malicious peers. This paper presents distributed algorithms that enable a peer to reason about trustworthiness of other peers based on past interactions and recommendations. Peers create their own trust network in their proximity by using local information available and do not try to learn global trust information. Two contexts of trust, service, and recommendation contexts, are defined to measure trustworthiness in providing services and giving recommendations. Interactions and recommendations are evaluated based on importance, recentness, and peer satisfaction parameters. Additionally, recommender’s trustworthiness and confidence about a recommendation are considered while evaluating recommendations. Simulation experiments on a file sharing application show that the proposed model can mitigate attacks on 16 different malicious behavior models. In the experiments, good peers were able to form trust relationships in their proximity and isolate malicious peers.