Research On Blockchain-based Secure And Efficient Traceability Scheme

Data tracing is the tracing of the original data and the evolution process.Users can understand the change process of the whole life cycle of data through the data traceability system.With the emergence of blockchain technology,it provides a new technical solution for secure storage and trusted computing in data traceability systems.The characteristics of decentralization,data sharing and non-tampering of this technology are very suitable for data traceability systems.However,there are many problems in blockchain-based traceability systems.Firstly,the performance of searching and querying historical data in the blockchain is low.At present,the mainstream blockchain systems usually have poor ability to search data,which will become the key performance bottleneck of data provenance systems.Secondly,the data in the blockchain system is disclosure and transparency,and any user in the system can access the original data.However,most blockchain-based data traceability systems do not consider protecting the security of stored data,or are not designed perfectly in data security storage,which will seriously threaten the data security of users.Finally,fine-grained access control is one of the essential functions of data traceability systems,but most of the existing works do not have this function.Therefore,how to ensure high search query performance while realizing data storage security and fine-grained access control function is an urgent issue to be solved.This thesis focuses on the search performance,secure storage and access control in the data traceability scenario.Firstly,the problems of blockchain-based traceability system are analyzed.Secondly,the relevant domestic and international research is collated.Finally,our solution is proposed.The main contributions of this thesis are as follows:(1)Considering the large data storage capacity and high query frequency of data traceable systems,existing blockchain systems suffer from significant search data performance bottlenecks.This thesis proposes an efficient blockchain-based query scheme.In order to prevent the potential risk of data leakage,the proposed scheme does not synchronize the data to a third-party database,and instead directly optimizes it in the blockchain.Specifically,this thesis predefines the on-chain data format,optimizes the inter-block search through new fields,and designs a new resource-friendly and Merkle tree independent index structure to optimize the intra-block search.In particular,compared with other schemes,the proposed index structure requires the least storage overhead.Finally,the search scheme proposed in this thesis is simulated and tested.The simulation results show that the search performance of the scheme is significantly improved compared with the baseline.(2)Considering the security storage and access control functions required by the data tracing system,this thesis proposes a security tracing system with efficient search performance based on block chain.Specifically,on the basis of optimizing the search performance of blockchain based on the previous work,the security traceability system is further deeply integrated with cloud outsourcing technology,aiming to optimize the search response time of the whole system.By using searchable encryption and attribute-based encryption algorithm,secure data storage and fine-grained access control function can be realized.Finally,the system was simulated and evaluated in Hyperledger Fabric.The simulation results show that the system can realize the traceability and query function on the premise of ensuring the data security,and has good execution efficiency.