The key idea of our solution is to use the powerful storage and computational capacities of the massive network of smartphones. We assume that the smartphones are registered on the crowdsourcing platform. The platform works as a coordinator between data owners and service requestors (i.e., data users). It shifts most workload to the smartphones of data owners, and thus is light weighted and scalable. For privacy protection, we apply cryptography techniques. We ensure that the service requestors will get
aggregated survey results, but will not learn personal information of any individual data owner, and the crowdsourcing platform will learn neither the information of individuals nor the aggregated survey results. In addition, different from existing work, by which data owners pass their data to survey agency and lose control on their data, our solution stores data at their owners’ smartphones and allow the owners to control how their data will be used