The Security Research Based On Sybil Attack In The Wireless Sensor Network

The Wireless Sensor Network which is for short WSN, is a kind of multiple hops and self-organization network which is composed of a lot of low-cost and resource-constrained sensor nodes which are deployed under some uncontrollable environment, and it achieves data collection and transmission via wireless communication mode. In recent years, with the continuous expanding of WSN network’s application field, there are more and more problems came out in the WSN network, which the security problem is becoming the most seriously challenge in the large-scale application of WSN network. There are various of attacks threating the security of the Wireless Sensor Network, where the Sybil Attack is a basic attack mode which is launched most easily.What’s more, it usually attacks network combined with other attacks and make much serious destruction for the WSN network.On the basic analysis of the disadvantages of some existing detection methods in terms of node energy-consumption and node calculation, and then it putting forward a method which utilizing the digital watermarking to detect the Sybil attack:using the node ID as the watermark, embedding it into the node data during the process of data transmission, and extracting the watermark after the data arrived at the base station. Then calculating the matching ratio between the real node ID and extracted node ID, and comparing it with the setting matching ratio threshold to find the Sybil node that cannot satisfy the matching ratio threshold. After lots of simulation and experiment, we find that this scheme not only can improve the detection rate of Sybil attack node and reduce the error rate of data information, but also can cut down the energy consumption of detection, and prolong the life cycle of the WSN network.The Directed Diffusion routing algorithm is a peculiar protocol in WSN network, and it centralize on data and realize the path selection by the query mechanism. But because of lacking of the secure mechanism of defending the Sybil attack, the application of DD algorithm is restricted seriously.In order to solve this problem, this paper makes a lot of improvement to the DD algorithm, and put forward a method that considering the node trust and Sybil attack parameters as the constraints of path selection, and taking safety inspection about the transmission path. In the modified algorithm, it compares the average value of all nodes’trust of path with the trust threshold that is required by the Sink node and determine the transmission path. Then comparing every node’s Sybil attack parameter with the setting threshold, and the node that cannot satisfy the threshold is the Sybil node, and it can keep away from this node and transmit data to the Sink node safely and integrality during data transmission. After theoretical and simulation analysis, it proves that the modified algorithm can detect the Sybil attack effectively, and guarantees the security of data transmission. Comparing the original DD algorithm, the new algorithm has higher security and be more suitable for the WSN network.