Trust Modeling and Evaluation

The performance of ad hoc networks depends on the cooperative and trust nature of the distributed nodes. To enhance security in ad hoc networks, it is important to evaluate the trustworthiness of other nodes without centralized authorities. In this paper, we present an information theoretic framework to quantitatively measure trust and model trust propagation in ad hoc networks. In the proposed information theoretic framework, the trust is a measure of uncertainty with its value represented by entropy. We develop four Axioms that address the basic understating of trust and rules for trust propagation. Based on these Axioms, we present two trust models: entropybased model and probability-based model, which satisfy all the Axioms. Techniques of trust establishment and trust update are presented to obtain trust values from observations. The proposed trust evaluation method and trust models are employed in ad hoc networks for secure ad hoc routing and malicious node detection. A distributed scheme is designed to acquire, maintain, and update trust records associated with the behaviors of nodes’ forwarding packets and the behaviors of making recommendations of other nodes. Simulations show that the proposed framework can significantly improve the network throughput as well as effectively detect malicious behaviors in ad hoc networks Copyright © 2004 URI 4 East Alumni Ave October, 2004 Kingston, RI 02881