Research On Techniques Of Energy-efficient Data Aggregation And Its Security In WSN

Wireless Sensor Networks (WSN) is currently one of the frontier and hot research fields in the world which has got much attention and possessed high integrative technology and multidisciplinary speciality. WSN expands the information acquisition ability of humans, and has a promising application prospect in many aspects such as national defense security and national economy. To protect the comprehensiveness of sensed data, numerous and dense-distributed sensor nodes will be deployed in the sensor networks, and all nodes will send the collected data which carry a mount of redundant information to the base station. As the power of sensor nodes is strictly limited and it is difficult to change the battery, studies aiming at the energy efficiency of WSN have always been the key and difficult problems in this research field. Data aggregation has become one of the important technologies about saving energy for wireless sensor networks. It can not only eliminate the redundant information of collected data and reduce data transfer volume, but also improve data accuracy and lower the energy consumption, thus prolonging the network lifetime effectively. Simultaneously, energy-efficient data aggregation algorithm becomes the key point of data aggregation investigation.With continuous operation of wireless sensor networks, the network communication cost is reduced greatly. However, new security problems will occur during the aggregation at the same time, such as privacy preservation of aggregated results, tampering with or forging aggregation data, capture of sensor nodes and information disclosure of aggregation nodes. Those nodes which have been attacked by malicious nodes can copy and then forward amount of fault or false information to other nodes in the network. These suspect and non-secure aggregation data will mislead the base station to make inappropriate response decisions, and plenty of captured sensor nodes will interfere or even stop the normal operation of the whole network, which will squander all the endeavors for data sensing. If the sensitive information is obtained by malicious nodes, the damage will be immeasurable. Therefore, it is significantly important to research on the security problems of data aggregation.On the basis of data aggregation in wireless sensor networks, we make an analysis on the design of efficient and energy-balanced aggregation strategies, and especially focus on the secure data aggregation algorithms based on node verification, privacy preservation, intrusion detection and homomorphic encryption. Main contributions of the dissertation are as follows:1. An energy-efficient data aggregation protocol in clustered WSN is proposed. Data aggregation schemes of clustered wireless sensor networks are investigated to solve the unbalanced energy consumption problem for nodes in the whole network. The situation of unbalanced load distribution of cluster heads under the multi-hop communication mode is analyzed, and a calculation method of cluster radius is proposed, which operates depending on the network topology and energy consumption of each cluster. As to the problem of rapid energy consumption of critical nodes in the network, a new cluster-leader election algorithm is proposed. Cross-level data transmission is introduced to reduce the total energy consumption of the network, and the efficiency of the algorithm is shown by an illustration and simulation.2. An energy-efficient anonymous aggregator election protocol in WSN is proposed. Security of cluster heads in clustered wireless sensor networks is investigated and an anonymous aggregator election protocol is proposed. The decision rules and cluster construction mode for anonymous aggregator election are presented. To ensure the successful election of cluster heads, an anonymous veto protocol based on bilinear pairings is adopted to verify the election results. For resisting some malicious behavior such as eavesdropping, node compromise and collusion attacks effectively, a corresponding data aggregation scheme is designed. Data aggregation can be accomplished through it without revealing their identities, providing high security for the aggregation procedure.3. An energy-efficient privacy-preserving data aggregation algorithm in WSN is proposed. Privacy-preserving data aggregation schemes in wireless sensor networks are investigated, and an energy-efficient, data loss resilient and privacy-preserving data aggregation approach is proposed. Two different forms of perturbation data are adopted to protect the data privacy of each node from being disclosed to the sink and any other nodes in the network. Firstly, from the point of view of sink intrusion, we describe the initial perturbation data scheme. On the basis of it, we present the second data perturbation with the index construction method. To resist various external attacks efficiently, the technique of message authentication code is introduced, and operation procedures of aggregation validation for intermediate aggregators and the sink are presented.4. An energy-efficient privacy-preserving aggregation scheme for multi-dimensional data is proposed. Privacy-preserving data aggregation algorithms for multidimensional data are investigated, and a privacy-preserving multidimensional data aggregation scheme which is suitable for smart grid communications in digital communities is proposed. A smart grid communication model in digital communities is established. The privacy homomorphism encryption technique and aggregation signature scheme are analyzed, based on the integration of which, the aggregation validation and integrity verification scheme are presented. To resist random errors, a construction method of member list is given, and the security, high-efficiency and feasibility of this scheme in smart grid communication are analyzed emphatically.