| Information superiority in future network centric warfare requires bandwidth efficient data dissemination to the right person at the right time. Using multicast for data dissemination in tactical mobile ad hoc networks poses security challenges. In particular, since an encryption key is needed for sending and receiving packets to and from each multicast group, the number of keys available to the communication module of a node (typically within the radio) for multicast communications limits the number of multicast groups the node can participate. Moreover, since dynamic key distribution is a complicated process, a more realistic key management approach is for each node to secure keys for a set of planned multicast groups prior to mission deployment, which hinders the flexibility of forming adhoc (unplanned) multicast groups during mission execution.
This paper presents a secure content based routing approach for information dissemination in tactical networks. In this approach, subscription is expressed in terms of data contents, which is more general and flexible than a single multicast address, and eliminates the complex multicast address planning problem that is present in current-day tactical networks. Secure dissemination is founded on a novel grouping concept that differentiates nodes participating in information dissemination from those sharing same data interest at a certain time. This differentiated grouping concept enables the use of a static key management approach for secure communication among trusted nodes, and at the same time facilitates nodes to subscribe to contents selectively. To be bandwidth efficient, the proposed approach establishes routing paths taking into account overlapping information needs of different users. Instead of examining packet contents, which could be a security threat, intermediate forwarding nodes can employ efficient bandwidth utilization techniques based on content markup in packet headers.
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