Research On Trajectory Privacy Protection Mechanism In Location Services

With the rapid development of modern intelligent equipment,wireless communication and positioning technology,Location Based Services(LBS)has become increasingly popular.Although location based services have brought people a new way of life,the extensive use of location-based services will produce a large number of trajectory data,which contain rich spatio-temporal information.Once leaked,the privacy of users will be threatened.Therefore,it is urgent to design an effective trajectory privacy protection scheme.However,most of the existing trajectory privacy protection schemes ignore the attacker’s background knowledge.If the attacker has more background knowledge,the user’s privacy information can still be obtained by analyzing the user’s location trajectory information.Aiming at the existing challenges and problems of mobile terminal users’ trajectory privacy in LBS,this paper focuses on anonymous technology and trajectory privacy protection technology.The main contributions are as follows:(1)In order to prevent the privacy leakage caused by background knowledge attack,a trajectory privacy protection scheme based on differential privacy is proposed based on differential privacy technology.Based on the theory of elliptic curve cryptography,the scheme uses differential privacy technology to add several Laplacian noise to the user ’ s trajectory data set to generate noise trajectory data set,and the pseudo user with noise trajectory data set replaces the real user to perform LBS requests.The security analysis and simulation results show that the scheme meets the security requirements of user privacy protection,and has good data availability.(2)In order to further prevent the trajectory privacy of mobile terminal users from being leaked,a K-anonymous trajectory privacy protection mechanism based on differential privacy is proposed by using the basic ideas of differential privacy and Kanonymous.The scheme uses differential privacy technology to generate a noise trajectory by adding Laplacian noise to the user trajectory repeatedly.Then,according to the trajectory similarity and K-anonymity idea,the noise trajectory with the highest similarity with the user trajectory is selected.The noise trajectory corresponds to a noise user.An anonymous user group is composed of a noise user and a real user,and the LBS request is launched as an anonymous user group.The security analysis and simulation results show that the scheme satisfies various security characteristics,and effectively improves the trajectory similarity of noise trajectory.There are 17 figures,10 tables,70 references in this paper.