Aggregation Supportive Authentication in Wireless Sensor Networks: A Watermark Based Approach

In-network processing presents a critical challenge for data authentication in wireless sensor networks (WSNs). Current schemes relying on message authentication code (MAC) cannot provide natural support for this operation since even a slight modification to the data invalidates the MAC. In this paper, based on digital watermarking, we propose an end-to-end approach for data authentication in WSNs that provides inherent support for in-network processing. In this scheme, authentication information is modulated as watermark and superposed to the sensory data at the sensor nodes. The watermarked data can be aggregated by the intermediate nodes without incurring any en-route checking. Upon reception of the sensory data, possibly distorted by the operations along the route, the data sink is able to authenticate the data by validating the watermark, detecting whether the data has been altered and where it has occurred. In this way, the aggregation-survivable authentication information is only added at the sources and checked by the data sink, without any involvement of intermediate nodes. Furthermore, the simple operation of watermark embedding and complex operation of watermark detection provide a natural solution of function partitioning between the resource limited sensor nodes and resource abundant data sink. The simulation results show that the proposed scheme can successfully authenticate the sensory data with high confidence.