Research On Blockchain-based Electronic Evidence Storage And Sharing

Electronic evidence is electronic data capable of proving relevant facts,and as a type of legal evidence,its manifestations in judicial practice are increasingly diverse,with the frequency of storage and the volume of data growing significantly.Traditional electronic evidence is usually managed centrally and is vulnerable to attacks and tampering during storage,transmission and sharing,reducing the credibility of the evidence.Blockchain,as a distributed technology,addresses issues such as data trust and security,and is suitable for the storage and transmission of electronic evidence for sharing.However,most existing models directly store evidence on the blockchain and use only the blockchain’s own asymmetric encryption in transmission,which is difficult to balance the cost and efficiency,is unable to satisfy the more complex access control requirements,and cannot well achieve the purpose of secure sharing.In view of this,this thesis combines blockchain and cryptography to carry out research in electronic evidence storage,access control and evidence sharing,as follows.（1）Aiming at the problems that conventional electronic evidence storage methods cannot ensure the security of electronic evidence easily and it is difficulty to balance storage overhead and efficiency,the research constructs a blockchain-based electronic evidence storage model,combines the Inter Planetary File System to store electronic evidence,optimizes the electronic evidence storage process based on directed acyclic graph,and improves storage efficiency.The experimental results show that the proposed model is better at improving the transaction throughput.（2）In order to effectively control the access rights of electronic evidence on the chain and meet the more complex access control requirements.A blockchain model for the whole process of access control from encrypted storage,request,acquisition to verification of electronic evidence is constructed under the dual-blockchain architecture,the data structure and organization of evidence storage is determined,and an access control protocol is proposed.The experiments verify the feasibility of the proposed model.（3）To solve the problem of secure sharing of electronic evidence,an electronic evidence sharing scheme is proposed in the blockchain environment based on distributed key generation technology and ciphertext policy attribute based proxy reencryption,and a multicenter model of evidence sharing combined with Inter Planetary File System is constructed.The analysis shows that the proposed scheme can meet the demand for secure evidence sharing and can achieve the purpose of fine-grained access control.This thesis proposes a solution of "evidence storage-access control-evidence sharing" in the whole life cycle of electronic evidence,which accumulates experience for further exploration of blockchain technology in the judicial field and provides feasible ideas for blockchain application in electronic evidence storage and sharing.