Mobile ad hoc networks are autonomous self-organized networks in which each node relies on the other nodes in the network to perform routing on its behalf. Proper functioning of the network is dependent on participation and cooperation of the nodes in routing and packet forwarding. Unfortunately, providing these services may not be in the best interest of a mobile node, since it results in the depletion of the node's resources. Selfish behavior by a node may result in degraded network performance due to denial of service, decrease in network throughput and partitioning of the network. Because it is in a node's interest to not forward traffic, nodes should be given some form of incentive for the services they provide.

In this paper, we address the problem of selfishness in mobile ad hoc networks by proposing a protocol called AD-MIX that encourages participation. AD-MIX discourages selfishness by concealing the true destination of packets from intermediate nodes along the path, forcing a node to participate or risk dropping packets destined for itself. Simulation results show that employing AD-MIX encourages participation without a significant increase in overhead. In addition to encouraging participation, AD-MIX also facilitates anonymization and secure communication between nodes.