An Improved Trajectory K- Anonymous Privacy Preserving Algorithm

With the development of wireless network technology and the wide spread of smart phones,mobile terminals,location-based services (LBS) has gradually integrated into people's lives,which is changing people's old mode of action. While people are enjoying the convenience of location services, another problem comes to the surface, which is a threat to the personal and property caused by the user's privacy. From 2003 to now, the researchers of location privacy protection technology was studied a series of fruitful research results.However, some problems occur for research workers .They began to realize that only the moving object location privacy protection is not enough. Malicious attacker use a known background knowledge of inference to attack continuous in location query service .If so ,the user's privacy will be exposed. Such as the user utilizes the time T1 or T2 anonymous box and the maximum speed as background knowledge,which leads the users' position to a higher probability of leakage and the extreme position will directly expose to the attacker.Aiming at the problem of using the maximum speed attack model to infer the user's location privacy .This paper is based on the generalization method. In the first place,the users who are in the same area are divided into an equivalent class by the same mode of travel in the area where the user is located. Secondly, the greedy circular construction method is used to replace the minimum bounding rectangle to divide the user into a circular area. Then analyzes the relationship between the location of the TJ user's location and the anonymous box in Ti, and proposes a MVA-Defence algorithm which can resist the maximum movement speed attack from Ti to TJ. Finally, the algorithm can resist the TJ to TI time of the maximum movement speed attack by means of adjusting to the TJ time of the anonymous space. K-algorithm is improved on the basis of MVA-Defence algorithm. Because a lot of query services to the final can be converted from the current position to the target location of the navigation,so the main purpose of this paper is to protect the trajectory of mobile users when using navigation services.The simulation results show that the performance of MVA-Defence algorithm is significantly improved compared with the maximum speed clique algorithm in terms of anonymous success rate, anonymous cost and anonymous delay. At the same time, it verifies the feasibility and effectiveness of the improved k- algorithm in the trajectory privacy protection.