Cooperative Authentication in Underwater Acoustic Sensor Networks
With the growing use of underwater acoustic communication (UWAC) for both industrial and military operations, there is a need to ensure communication security. A particular challenge is represented by underwater acoustic networks (UWANs), which are often left unattended over long periods of time. Currently, due to physical and performance limitations, UWAC packets rarely include encryption; thus, the UWAN is exposed to external attacks faking legitimate messages. We propose a new algorithm for message authentication in an UWAN setting. We begin by observing that, due to the strong spatial dependency of the underwater acoustic channel, an attacker can mimic the channel associated with the legitimate transmitter only for a single or a small set of receivers. Taking this into account, our scheme is based on the cooperative operation of a set of trusted nodes reporting to a sink node. For each incoming packet, the sink fuses beliefs evaluated by the trusted nodes to reach an authentication decision. These beliefs are based on estimated statistical channel parameters, chosen to be the most sensitive to the transmitter-receiver displacement. Our simulation results show accurate identification of an attacker's packet. We also report results from a sea experiment demonstrating the effectiveness of our approach.
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