Research On Key Technologies Of High Privacy Agricultural Traceability Based On Blockchain

With the rapid development of agricultural informatization,the quality and safety of agricultural products have been concerned,and the Internet of Things(Io T)has gradually become a necessary technology for agriculture.In order to solve the problems of data isolation,easy to modify and difficult to trace in the process of agricultural products from planting to sales,this thesis establishes a traceability model to improve transparency on the premise of protecting privacy.Furthermore,to avoid the problem of privacy disclosure in the process of traceability,database auditing technology based on blockchain technology is used to ensure database security and achieve high privacy of the system.Finally,a high privacy agricultural traceability system based on blockchain is proposed.The main researches and contributions of this thesis are as follows:(1)Aiming at the problem that the privacy of the agricultural traceability system is not high enough,this thesis studies the relevant contents of database audit.Based on searchable encryption technology,a ciphertext audit scheme on blockchain is designed,which reduces the risk of interception in the audit process and solves the problem that bypass monitoring cannot be used in the audit process.Furthermore,the proposed scheme can realize the supervision and audit of operation of data while ensuring the privacy of data among blockchain users.It has been proved that the scheme can meet the security requirements while maintaining high efficiency and improve the privacy of the system.(2)Aiming at the difficulty in balancing privacy protection and high transparency in agricultural traceability system,this thesis considers traceability consisting of the following three properties: trade privacy,preservation and noninvolvement.According to the above properties,we model traceability based on the hidden Markov model,and then the encryption algorithm based on Ring learning with error(RLWE)is used to encrypt the model.Subsequently,the model is verifiable by applying the noninteractive zero-knowledge proof of the knowledge that the plaintext is equal to zero.The transparency of consortium blockchain is improved on the premise of privacy protection.(3)Aiming at the problems of data isolation,easy to modify and difficult to trace in agricultural traceability,a high privacy agricultural traceability system based on blockchain is implemented based on Hyperledger Fabric and Inter Planetary File System(IPFS)storage.Furthermore,The local data is analyzed and visualized by the mode of on-chain storage and off-chain calculation.Io T devices periodically upload text data to smart contracts,remove redundant data and save it to blockchain.Images and videos are stored through IPFS distributed network,and the unique content index hash is obtained and saved to blockchain.Subsequently,it has been verified that the scheme is superior to the traditional traceability scheme in terms of stability and security,and can meet the requirements of Io T devices to upload data to blockchain concurrently in terms of performance.