Making Nodes Cooperative: A Secure Incentive Mechanism for Message Forwarding in DTNs

In traditional Delay Tolerant Networks (DTNs), the nodes can take advantage of intermittent contact opportunities to forward messages. However, in noncooperative DTNs, the nodes may be selfish and reluctant to cooperate with each other in message forwarding. Therefore, it is necessary to motivate the nodes to cooperate with each other in such DTNs. The previously proposed incentive mechanisms have obvious limitations such as the security vulnerability. To resolve such kind of drawbacks, in this paper we propose two credit-based rewarding schemes, called earliest path singular rewarding scheme and earliest path cumulative rewarding scheme respectively, to ensure the nodes truthfully forward the messages. The proposed rewarding schemes are incentive compatible. They also ensure that the payment for each delivered message is upper bounded. Furthermore, the proposed rewarding schemes can prevent selfish nodes from having malicious behaviors. Simulations based on the real trace are conducted to illustrate the effectiveness of the proposed rewarding schemes.