Research On The Security Problems In Data Aggregation Of Wireless Sensor Networks

Date aggregation has been used extensively in wireless sensor networks (WSNs) as an ideal energy-saving technique. It can effectively reduce redundant data generated in the information-acquisition phase, improve the efficiency of data transmission and the computing load of the sensor nodes, thereby prolonging the service life of the network and shortening the decision-making time. However, with the widespread application and rapid development of the data aggregation technique, many security problems have arisen related to the confidentiality, privacy, and integrity of the data. Attackers can disrupt the security performance of the network by eavesdropping, tampering, forgery, and other kinds of malicious behaviors. Therefore, one of the most important topics in research related to WSNs is developing ways to solve their security problems during the process of data aggregation.The focus in this thesis was to study and analyze the data aggregation techniques for WSNs and to assess network security technology by researching ways to protect the privacy of data, assessing node reputation evaluation mechanisms, and applying homomorphic encryption and the homomorphic MAC technique in WSNs. The research of the dissertation was supported by National Natural Science Foundation of China (No. 61371071), Beijing Natural Science Foundation (No.4132057), and the Academic Discipline and Postgraduate Education Project of Beijing Municipal Commission of Education. The major research results and contributions of this thesis are as follows:(1) In this thesis, a secure data aggregation scheme is proposed based on dynamic data slicing and mixing. The proposed scheme allows the preservation of privacy by the dynamic segmentation of collected data, which makes it difficult for eavesdroppers to acquire or restore any of the data. In addition, the proposed scheme can greatly reduce the communication overhead and computing load of sensor nodes while simultaneously providing good performance in preserving privacy. The simulation results showed that the proposed scheme was superior to similar schemes in saving energy and in the accurate aggregation of data. It is an efficient, secure, data-aggregation scheme that can be used in many practical applications.(2) In this thesis, a reputation-based secure data aggregation scheme for WSNs is presented that can resist internal attacks. The proposed scheme monitors node behaviors by the use of the’ Watch Dog’ mechanism and the local outlier detection mechanism. And according to the behavioral characteristics of the sensor nodes, the proposed scheme provides the corresponding characteristic indexes. In the process of data aggregation, if the behavioral reputation of a node is lower than the preset threshold, the node will be identified as malicious node and isolated from the network. The simulation results indicated that, compared to similar schemes, the proposed scheme effectively detected malicious behaviors with a lower level of energy consumption, and it improved the accuracy of data aggregation.(3) In this thesis, an elliptic-curve, cryptography-based secure data aggregation scheme with integrity protection is proposed. The proposed scheme achieved end-to-end, secure data aggregation due to its additive homomorphic elliptic curve encryption mechanism. The private data of sensor nodes remain encrypted during the process of data aggregation, and the aggregator nodes can perform direct aggregation to the ciphertext, thereby ensuring the confidentiality and privacy of the data. Meanwhile, the proposed scheme provides a mechanism for verifying the integrity of the data by constructing two independent aggregation trees. The results of simulation and security analysis indicated that the proposed scheme has good performance in security, communication overhead, and the accuracy of data aggregation.(4) In this thesis, a secure data aggregation scheme is proposed based on the technique of homomorphic message authentication code. The proposed scheme protects the confidentiality and privacy of the data by using homomorphic encryption. Also, the mechanism of homomorphic message authentication code can verify effectively the integrity of data aggregation results. The simulation results showed that, compared with similar secure data-aggregation schemes, the proposed scheme achieved better performance in the accuracy of aggregation, communication overhead, and computing load.