Preventing Unauthorized Messages in DTN Based Mobile Ad Hoc Networks

Maintaining user connectivity over heterogeneous wireless networks will be a necessity with the wide spread of wireless networks and limited network coverage. In, we propose a super node system architecture based on the concept of delay tolerant networks (DTN) to overcome roaming user intermittent connection over interconnected heterogeneous wireless networks. Mobile ad hoc network plays a key role in the super node system as it can provide a coverage for areas that lack a network infrastructure to bridge the gaps between wireless networks within the system. Long delays combined with the lack of continuous communication with a network manager introduce new security challenges for mobile nodes in a DTN environment. One of the major open challenges is to prevent unauthorized traffic from entering the network. This paper addresses this problem within the super node system. Two schemes are proposed: one is based on asymmetric key cryptography by authenticating a message sender, and the other is based on the idea of separating message authorization checking at intermediate nodes from message sender authentication. Consequently, the second scheme uses symmetric key cryptography in order to reduce the computation overhead imposed on intermediate network nodes, where one-way key chains are used. A simulation study is conducted to demonstrate the effectiveness of each scheme and compare the performance with and without using an authorization scheme.