Research On Spatial Location Privacy Protection Mechanism Satisfying Geo-Indistinguishability

Various location-based services can provide location-related information retrieval,traffic navigation,entertainment services,emergency rescue,and other services based on the premise of obtaining the spatial location of users or mobile devices.While providing a new user experience,location-based services may also easily expose the specific location of users or devices,leading to more privacy information leakage such as home address,places of interest,and exercise routes.Therefore,the protection of user and mobile terminal location privacy is one of the key issues that needs to be addressed in location-based services.(1)Considering that the areas where users work and live have different location semantics and sensitivities based on different social functions,although the real location can be protected by perturbation algorithms,attackers can still infer and spy on user privacy based on the semantic information of the perturbed location.To mitigate privacy leakage caused by such semantic inference attacks,a user-side location perturbation and optimization method based on geo-indistinguishability and location semantics is proposed.This method first uses a planar Laplace mechanism to generate a perturbed location area that satisfies geo-indistinguishability;then,the perturbed location area is optimized based on location semantic information and its time characteristics to remove locations with high similarity to the user’s real location semantics;finally,the optimal localized perturbed location is selected from the remaining perturbed location area by using linear programming method,with the lowest loss of location service quality as the objective function,and is sent to the location service provider as a substitute for the user’s real location.Experimental analysis based on actual check-in datasets shows that the proposed method outperforms other existing location perturbation methods in terms of service quality loss,privacy protection strength,and spatial range query accuracy.(2)Existing user-side location privacy protection methods mostly apply to 2D plane locations.With the widespread use of aircraft,space sensing devices,and space information acquisition devices with positioning functions,new methods that can achieve 3D spatial location privacy protection are urgently needed.Therefore,this paper proposes a spatial GPS coordinate perturbation method that satisfies 3D geoindistinguishability.This method first constructs a spherical coordinate system for the perturbed location based on 3D geo-indistinguishability;then,it uses a 3D Laplace mechanism to generate perturbed locations in the spherical coordinate system;finally,with the help of analytical geometry,the perturbed coordinates in the spherical coordinate system are converted into the longitude,latitude,and height of 3D GPS coordinates,realizing point-to-point perturbation and privacy protection of 3D spatial GPS coordinates.The experimental analysis on a real 3D spatial location dataset shows that,under the same privacy budget,the 3D spatial location perturbation method proposed in this paper has better location service quality,data availability,and execution efficiency than other existing methods.