Distortion-Free Watermarking Scheme for Wireless Sensor Networks

Wireless sensor networks have spread widely in the recent years. They have a very wide range of applications such as environment monitoring and military applications like battlefield monitoring. Sensors and their data are vulnerable to various attacks, like data injection, deletion, modification or even node replacement. Because of the resource limitation, security mechanisms that are based on traditional security techniques like public key cryptography and digital signatures are too heavy for wireless sensor networks. Watermarking is considered an attractive alternative because of its light resource requirements. This paper proposes a new technique for providing data integrity for wireless sensor network. The proposed scheme is based on distortion free watermarking. Most of the prior works embed the watermark by replacing the least significant bits of the data. While some applications can tolerate small errors in the data readings, other applications are sensitive to errors. The proposed watermarking technique embeds the watermark in the order of the data elements, and thus, does not cause distortion to the data items. We provide a detailed security analysis to show the robustness of the proposed techniques against various types of attacks. The proposed technique is implemented and the performance, in terms of the attack detection rate and the ability to identify the victim element is evaluated. In case of single attack the proposed technique can identify the victim data reading with high probability (up to 95%). The cost in terms of the execution time of the watermark calculation and embedding is also measured.