Research On Node Secure Localization Algorithm Against Wormhole Attacks In WSN

The localization algorithm of Wireless sensor networks holds more and more attention of researchers, and has become one of the hot research areas. When deployed in the bad environment, the wireless sensor network is vulnerable to the external attacks. For the range-free algorithms, they may be severely affected by some attacks which can disorder network topology, such as wormhole attacks. Thus, a safe, effective and precise localization algorithm plays a vital role for wireless sensor network applications.First of all, this paper designs a safe localization algorithm based on a mobile beacon node. In the algorithm, a reasonable reference position is selected firstly for the unknown nodes through sorting ascending those messages received from the beacon node, and then compared with the other positions so as to find out those valid messages, and reduce the impact of wormhole attacks. Simulation experiment proves that the algorithm can resist effectively wormhole attacks. But in practical applications, this algorithm may not show ideal effect in the environment where human can not reach, because the starting position and move trajectory of mobile anchor node both need elaborate design.Secondly, considering the DV-Hop algorithm can be used in the random- deployed network, but is susceptible to the wormhole attack, this paper then devises an algorithm against wormhole attacks through improving the DV-Hop algorithm from three aspects:1) It puts forward a new method which is used to calculate and replace the hop between two beacon nodes when the wormhole attack is discovered. Nonlinear formula is designed to calculate the hop, so that the hop is more close to the real value;2) It presents a method to determine the position of wormhole link. Using this method, we not only can confirm the position of the wormhole link, but also count up the number of nodes affected directly by wormhole attacks;3) It determines whether to reposition according to the statistical node number. If necessary, the data got during the first positioning is used to bypass wormhole links.Finally, the algorithm above is improved further and applied to the secure localization in three-dimensional environment. Theoretical analysis and simulation results show that the proposed algorithm does not need auxiliary and expensive hardware, can resist wormhole attacks effectively only through calculation, so the algorithm is not only easy to implement, but also has low traffic and relatively small localization error, therefore it is suitable for the large-scale network applications.