A secure incentive architecture for ad hoc networks

In an ad hoc network, intermediate nodes on a communication path are expected to forward packets of other nodes so that the mobile nodes can communicate beyond their wireless transmission range. However, because wireless mobile nodes are usually constrained by limited power and computation resources, a selfish node may be unwilling to spend its resources in forwarding packets which are not of its direct interest, even though it expects other nodes to forward its packets to the destination. It has been shown that the presence of such selfish nodes degrades the overall performance of a non-cooperative ad hoc network. To address this problem, we propose a secure and objective reputation-based incentive (SORI) architecture to encourage packet forwarding and discipline selfish behavior. Different from existing schemes, under our architecture, the reputation of a node is quantified by objective measures; the propagation of reputation is efficiently secured by a one-way-hash-chain-based authentication scheme; and secure routing is in place. Armed with the reputation-based mechanism, we design a punishment scheme to penalize selfish nodes. The experimental results show that the proposed scheme can successfully identify selfish nodes and punish them accordingly. Copyright (c) 2006 John Wiley & Sons, Ltd.