Research On Location Privacy Protection Algorithm For Social Relations

With the combination of social networking and location-based services(LBS),location based social network(LBSN)is formed and a series of LBSN services are derived,where location sharing service and check-in service are important services in LBSN.In these services,users have to provide their own real location information to the service provider.As a result,users enjoy the convenience provided by LBSN server,but also face the threat that their location information may expose to LBSN server.For users,location information is extremely sensitive information,which can lead to some serious privacy issues,including identity,health,and so on.The difference with LBS is that LBSN also involves other privacy issues,such as social identity privacy,social network privacy and other privacy issues.In LBSN,exposure of other privacy may lead to exposure of users' location privacy.First,the author studied location privacy issues in location sharing services.In the existing research,location sharing services,such as the nearby friends' location query service,does not take the issue of friends attack into account.In fact,users are likely not trust all of his friends,so thesis allows users to share location information with a part of specified friends.In addition,users' social identity privacy,location privacy and social network privacy should be safeguarded.Therefore,author proposes a new location query algorithm.Algorithm of thesis is mainly to blur users' query results to all pseudonyms and its corresponding location in the specified query range.Author has a security analysis of our query algorithm.The datas show that query algorithm of thesis is more secure than the existing query algorithm.At the same time,author also conducted extensive simulation experiment for query time.And the simulation results show that the proposed query algorithm in thesis is more efficient than the existing query algorithm.Secondly,the author also studies the location privacy problem of “check-in” service in LBSN,and puts forward the dummy location selection protocol,check-in protocol,search protocol,join protocol,and revocation protocol.Scheme in this thesis allows users to obtain check-in rewards and presents a location privacy preserving algorithm based on the method of k-anonymity.When users check in,the algorithm would take users' side information into account to carefully select dummy locations.At the same time,author improved the index structure.Thus,the scheme proposed in the thesis allows users to fast search by specified location and friends' social networks identity.Author has a security analysis of scheme in the thesis,and analytical data shows that scheme proposed in the thesis has a well protection of location privacy throughout the process of check-in,store check-in record and search check-in record.Finally,author did a large simulation experiments.The simulation results show that the performance of protocol proposed in the thesis is great advantage in terms of security.