Towards a reputation-based routing protocol to contrast blackholes in a delay tolerant network

A Delay Tolerant Network (DTN) relies on the implicit assumption that nodes cooperate towards message forwarding. However, this assumption cannot be satisfied when there are malicious nodes acting as blackholes and voluntarily attracting and dropping messages. In this paper we propose a reputation-based protocol for contrasting blackholes. Every node locallymaintains the reputation of forwarding nodes it comes in touch with and, then, upon selecting the next forwarding node, the node chooses among those having the highest reputation. The proposed reputation protocol is composed of three basic mechanisms— acknowledgments, node lists, and aging—that make communication efficient and capable of adapting to the changing operating conditions of a DTN. The protocol has been used to extend CAR [1]. The resulting protocol RCAR (reputationbased CAR) has been compared with T-ProPHET [2], a state-of-the-art reputation-based DTN routing protocol, from several standpoints. As it turns out, RCAR is more effective than T-ProPHET and outperforms it in most cases. ! 2012 Elsevier B.V. All rights reserved.