Research And Implementation Of Privacy-preserving Spatial Crowdsourcing Platform

With the rapid development of the mobile Internet technology and improvement of computing ability of GPS-equipped devices,the concept and pattern of spatial crowdsourcing play an important role in social service,intelligent transportation,environment monitoring and so on,receiving widespread concern from industry and academia.In a typical spatial crowdsourcing application,the user needs to send their private location information to the platform for a global optimal task assignment schema.However,the untrustworthy platform and potential external attackers inevitably brings about a threat to workers location privacy.In this paper,we propose a novel privacy-preserving spatial crowdsourcing model based on existing technology.In addition,we design and implement the corresponding prototype system called PP-SC-Sys.Specifically,our work covers the following several aspects:(1)We thoroughly study the existing technology and method of spatial crowdsourcing and privacy protection,elaborate the development track and research status of privacy-preserving spatial crowdsourcing in detail,and summarize the advantages and disadvantages of different categorized privacy-preserving model,laying a solid foundation for our work.(2)We propose a novel anonymity based privacy-preserving model.In the model,the private location data of workers will be generalized to travel cost,then the travel cost data will be encrypted by bitwise XOR homomorphic cipher and be transmitted to platform safely by anonymity based data aggregation protocol.After receiving data,the platform will generate task assignment and payment schema via reverse auction based task assignment algorithm.At the moment,the algorithm will guarantee the truthfulness of submitted data.Theoretical analysis and experimental results both show that our approach is secure and efficient.(3)Based on proposed privacy-preserving spatial crowdsourcing model,we design and implement the corresponding prototype system called PP-SC-Sys,which is a Web app.The Web app shows how to protect location privacy in spatial crowdsourcing,further validating the validity of our model and demonstrating the value of our work.