Trust threshold based public key management in mobile ad hoc networks

Public key management in mobile ad hoc networks (MANETs) has been studied for several decades. However, the unique characteristics of MANETs have imposed great challenges in designing a fully distributed public key management protocol under resource-constrained MANET environments. These challenges include no centralized trusted entities, resource constraints, and high security vulnerabilities. This work proposes a fully distributed trust-based public key management approach for MANETs using a soft security mechanism based on the concept of trust. Instead of using hard security approaches, as in traditional security techniques, to eliminate security vulnerabilities, our work aims to maximize performance by relaxing security requirements based on the perceived trust. We propose a composite trust-based public key management (CTPKM) with the goal of maximizing performance while mitigating security vulnerability. Each node employs a trust threshold to determine whether or not to trust another node. Our simulation results show that an optimal trust threshold exists to best balance and meet the conflicting goals between performance and security, by exploiting the inherent tradeoff between trust and risk. The results also show that CTPKM minimizes risk (i.e., information leakout) using an optimal trust threshold while maximizing service availability with acceptable communication overhead incurred by trust and key management operations. We demonstrate that CTPKM outperforms both existing non-trust-based and trust-based counterparts.