Research On Privacy Protection Method Based On Continuous Queries Of Location-based Services

With the continuous development of Internet technology and the popularity of smart mobile phone, location-based service has become indispensable query helper in daily life. Compared to the traditional web service privacy problem, LBS privacy could cause more attention to the researchers for LBS requiring the users to provide accurate, real-time and continuous position information to the service provider to ensure the quality of service. However, exposing location information could bring serious privacy concerns to users. At first, as special identification information with regional characteristics, location information may expose the identity of the users to the attacker under the multiple tracks to the location information. Then, the tracks of the attacker to multiple adjacent location point forming the moving trajectory of the user may expose the trajectory of the user which also led to more exposure of privacy. How to giving effective methods for the problem of trading off between location privacy protection and quality of service is an important content in the research of location privacy. In order to solve the two kind issues of privacy protection for LBS, this paper proposes the methods of location privacy protection and trajectory privacy protection, respectively, on the basis of the analysis of methods of privacy protection for LBS. The major work is listed as follows.Firstly, the multiple queries of the user may make the attacker eliminates other users based on the comparison, and lead to the exposure of the location information for the static continuous query. This paper proposes the method of location privacy protection based on the spatio-temporal cloaking which generalizing the same location to different cloaking areas at different times based on the privacy requirement of the user. This paper also expounds the processing method of query process, and the analysis of experimental results verifies the effectiveness of the proposed method.Secondly, the attacker may construct the moving trajectory of the user based on the multiple queries at different location for the dynamic continuous query. This paper proposes the method of trajectory privacy protection based on the road-network Mix-zones which giving the typical attack models, and giving the road-network Mix-zones model based on the typical attack models. This paper also expounds the construction method of the mix-zones and verifies the feasibility of the proposed method through experimental analysis.Finally, according to the proposed methods of location privacy protection and trajectory privacy protection, respectively, this paper designs and implements the location service privacy client tool. According to the above proposed method of privacy protection, the tool protects privacy information of users while returning the candidate results met the user's requirements based on the privacy requirements. At last, a case study demonstrates the process of the system, and the feasibility and effectiveness of the method proposed in this paper.