Research On Watermark-based Data Integrity Protection In WSN

Wireless sensor networks (WSNs) are self-organizing network systems, which have a broad application prospects in the military, medical, the public safety and so on. The sensor nodes are deployed in the monitoring area, collecting the real-time monitoring data for the analysis of the situation. The accuracy and security of the data will affect the users'judgments directly. However, because of WSNs'inherent constraints, such as the resources and computing ability, a number of traditional data protection technologies can not be directly applied into the current wireless sensor networks. And the data in the WSNs is facing to a variety of threats, such as forgery or tampering attacks. Therefore, ensure data integrity in the sensor networks becomes very urgent.The paper, which is based on part of the national 973 projects undertaken by our lab——"Research on basic theory and key technologies of Wireless Sensor Network", considers the security issues in the wireless sensor network. And mainly applies the digital watermarking technology to resolve data integrity protection in the WSNs. The main contributions are as follows:1) A data integrity protection scheme based on the association watermarking technology is proposed in the WSNs. The collected data is divided into a number of successive fixed-size sets decided by the size of the buffer. Without influencing the use of the data, the watermarking information generated by the associated relationship among the data is embedded into it, using the embedding rules. When the SINK node receives the set of the data, then re-calculates the associated relationship between the data while extracting the watermarking information. The SINK verifies the integrity of the data by comparing that the two values are equal or not. In this algorithm, the watermark is hidden in the protected data, so the protection has a strong disguise. At the same time, according to the strong collision-free hash function properties, we could find any small changes of the data in the transmission. And the experimental results show that this method can fully ensure the data integrity.2) A data integrity protection scheme based on the digital watermark during the data fusion is proposed in the WSNs. The cluster heads process multiple copies of the data or information by using the temporal-spatial correlation of data, combining with the data fusion technology. The fused data becomes more effective and more closely to the one which the users need, and drop the unnecessary data to extend the life of the WSNs. After the data fusion, cluster heads complete the watermark embedding algorithm, instead of transferring the data immediately. The watermark information is embedded into the fusion data to protect the integrity of the sensor data.3) Setting up the network simulation platforms. The simulation results in the OMNET++environment show:the two kinds'of scheme can effectively achieve the integrity protection of the data with low energy consumption in the wireless sensor network. The first fragile watermarking scheme is more suitable for high precision data in the traditional network model of integrity protection; the second semi-fragile digital watermarking scheme is more suitable for the data fusion in the distributed network model of data integrity protection.