Location Privacy-preserving Technology Research Based On Blockchain

With the development of science and technology and the improvement of people's living standard,Location Based Service(LBS)has been more widely applied in daily life.it bring convenience to people's lives but are also accompanied with privacy leakages.When users use LBS,they must share location information and query information.Attackers may steal users' privacy through data mining and other technologies or channels,which will bring serious threats to users.To solve this problem,many location privacy protection algorithms have been proposed.However,these algorithms often have difficulty to maintain a balance between service quality and user privacy.Therefore,the focus of this paper is to use the decentralized location privacy protection architecture to better balance the location service quality and user privacy.In this paper,the main research work of location privacy protection technology is as follows:(1)In-depth understanding of the current situation of location privacy protection,research and analysis of location privacy protection technology and its principles at home and abroad.This paper first summarizes the advantages and disadvantages of the two existing location privacy protection architectures and location privacy protection technologies,and proposes a novel location privacy protection architecture based on blockchain technology.Two different location privacy protection schemes are proposed on this architecture.(2)Propose a location privacy protection method based on multi-chain combination.Both user and LSP are registered on the public blockchain,and LSP together creates an alliance blockchain.When users think that the location sensitivity in their query request is low,they can use less currency to obtain the location services on the public blockchain: the system first searches the historical transaction record on the public blockchain,and if there is the same location query,deduct the user's less currency to other users to obtain the historical transaction records;if not,the LSP directly returns the query results and records the new block,generating a new transaction record.When the user thinks that the position sensitivity in the query request is high,the query request is issued on the alliance blockchain,and the LSP directly returns the query result.The published query requests use the k-anonymity technology to construct anonymous area.The advantages of this method is that the blockchain plays the role of a third party,but overcomes the weaknesses of the third party;the blockchain does not require users to provide real identities,users can register as many accounts as they want to post query requests,and the combination of public and alliance chain disperses user's transaction records.Combining with k-anonymity technology,high-quality location services can be obtained.Finally,the simulation experiment proves the feasibility of the system.(3)Propose a location privacy protection method based on private blockchain.User can create private blockchain or join private blockchain created by other user,and then post query requests on the private blockchain as a requester,or as an agent to undertake query services.This method also uses k-anonymity technique to construct the anonymous region.Similar to(2),the combination of multiple private blockchains decentralizes users' transaction records,provides users with stronger location privacy protection,and combines k-anonymity technology to provide users with higher location service quality.Compared with the public blockchain,multiple private blockchain improves the performance of the system,and the scheme uses agents to cut off the direct contact between the user and the LSP,which further improves the privacy protection ability of the system.In addition,the program also proposes an arithmetic reward mechanism to encourage user participation and improve system efficiency.Finally,implement the method in Remix to show efficiency and feasibility.