Research On Location Privacy Protection Technology To Continuous Queries

As a kind of application which is closely related with people's daily life, the location service has developed rapidly in various fields, and has been widely accepted by people. In the practical application, users need to send their precise location information to the location service provider. However, the untrusted location service providers as well as malicious attacker's illegal attacks pose a security threat to the user's location information. At the present stage, the research of location privacy protection is mainly focused on the snapshot query, but the research on privacy protection of continuous query is relatively less. Therefore, how to protect the user's location privacy security is an urgent problem to be solved in the application of continuous query location services. In order to solve the problem of user location privacy for continuous queries, this paper studies and analyzes the privacy preserving technology of continuous query. The details of research works and innovation are as follows:1. Aim at the location privacy leakage problem caused by the anonymous space region intersection attack in the location service of continuous query, this thesis presents a privacy protection algorithm of pseudonym dynamic generation based on location cloaking. The main ideas are as follows: First, we use the data structure of quadtree and Euclidean distance to find the best anonymous spatial region; Secondly, use anonymous set update algorithm to establish the graphic data storage structure for the union of the current anonymity set and historical anonymity set, then create vertex adjacency matrix to determine whether the current anonymity set can be safe to release; Finally, the hash function is used to deal with the anonymous set which cannot be safely released, and generate a pseudonym for the query requester, so as to achieve the purpose of protecting the privacy of the users location.2. Aim at the location privacy leakage problem caused by the maximum speed attack in the location service of continuous query, this thesis presents a privacy protection algorithm of enhanced time cloaking. The main ideas are as follows: First, use the Hausdorff or point to point distance metric method to determine whether the anonymous spatial region can be safe to release, and calculate the maximum delay time that can be released safely; Secondly, create Minkowski sum for the anonymous space region of the previous moment; Eventually, look for the anonymous space region that meets the user's personalize privacy needs by using the four quadrant partition method in Minkowski sum, and loop the last two steps in the maximum delay time until finding the area, and then it can reduce the time error and space error effectively under the premise of the realization of the user's location privacy security.