Abstract: The popularity of location-based services(LBS) has brought great convenience to people’s life,but it also brings serious privacy leakage at the same time.Dummy is a popular technology at present,but most existing methods do not take the individual needs of users into account.To address this problem,a improved privacy model was proposed,guided by which we designed a dummy trajectories generation algorithm.The model includes five reasonable parameters,namely short-term disclosure,long-term disclosure,trajectories distance deviation,trajectories local similarity and services request probability.People can customize these metrics through their own needs and generate dummies by dummy trajectories generation algorithm to avoid leakage of privacy.The experiment results show that the algorithm can generate fewer dummy trajectories to satisfy the same privacy-preserving requirement.So it’s more effective than exis-ting works in preserving movement trajectories,especially the probability of services request is discussed.

Key words: Location-based services(LBS),Trajectory privacy,Privacy model,Pseudonyms-based anonymization