Blockchain-based User's Location Information Secure Sharing Scheme

With the rapid development of positioning technology,location-based service(LBS)has become an indispensable part of social life and national economy including transportation,social activities,medical industries,militaries and so on.With the rapid popularization of wireless network technology and continuous enrichment of related applications,LBS has become more comprehensive and convenient,and has broad application prospects.LBS is to provide location-related services to users by means of location sharing.In traditional centralized management mode,privacy disclosure caused by third party poses huge security risks to users.Considering the distributed data storage mode and openness and autonomy of the blockchain,this thesis adopts blockchain to realize the decentralized storage of location information.On this basis,this thesis researches and designs a multi-level privacy preserving location sharing scheme,which eliminates the security problems caused by third party and realizes the secure sharing of user's location information.The main research results of this thesis are as follows:1.The model of blockchain-based location sharing scheme is researched and constructed.This thesis constructs the system model of the scheme by analyzing the application scenario and architecture of the location sharing mechanism.On this basis,according to the members' potential aggressive behaviors,this thesis constructs the threat model and summarizes the security goals of the location sharing scheme in decentralized mode,including unforgeability,confidentiality,multi-level privacy preserving,verifiability and retrievability.2.According to the model of location information sharing mechanism,this thesis studies the blockchain-based interactive multi-level privacy-preserving location sharing scheme(IMPLS).I-MPLS is constructed based on blockchain,order-preserving encryption,Merkle hash tree and other techniques,and the security analysis proves that I-MPLS can satisfy all the security goals.3.According to the model of location information sharing mechanism,this thesis studies the blockchain-based non-interactive multi-level privacy-preserving location sharing scheme(NI-MPLS).To avoid the cost of location information communication outside the blockchain,this thesis adopts attribute-based encryption based on I-MPLS and designs NI-MPLS.Finally,the security analysis proves that NI-MPLS can satisfy all the security goals.4.This thesis tests and analyzes the performance of the proposed schemes.In this thesis,the performance of I-MPLS and NI-MPLS is compared and analyzed,and the differences between I-MPLS and NI-MPLS are mainly reflected in applicable scenario,dynamic control of multi-level privacy preserving and the computation cost.The computational cost in each phase of the schemes is tested and compared.Finally,by comparing with other related schemes,only the proposed schemes in this thesis can satisfy all the security goals.