| After obtaining legal status in our country,electronic evidence began to be used on a large scale in judicial cases.However,traditional electronic evidence is stored in a centralized system.Once the system is attacked by hackers,it will face the risk of data loss,and the data is easy to be tampered with,and it is difficult to guarantee the data and user privacy.Thus,this paper proposes a judicial electronic evidence system based on the Fabric consortium blockchain and homomorphic encryption to solve the problems above.The main research contents are as follows:(1)To solve the problem that the data is easily lost and tampered after the traditional centralized judicial electronic evidence system is attacked by hackers,this paper proposes to build a distributed judicial electronic evidence system based on the Fabric consortium blockchain and Interplanetary File System(IPFS).And the system is mainly divided into node management layer,blockchain service layer and application layer.First of all,in the node management layer,authorized Internet courts at all levels,judicial notaries and other institutions can participate in the blockchain network in the manner of nodes,and all nodes joining the network are synchronized through data to avoid data being single node tampering,and a single node will not cause data loss after being hacked.Secondly,the blockchain service layer contains functions such as identity authentication,trusted timestamp,data storage,etc.Among them,the identity authentication function can assign corresponding permissions to users who use the system,realize access control,and avoid unrelated personnel modification judicial electronic data.Trusted timestamps can implement unified time services for the system,avoiding consensus problems caused by time inconsistencies.Moreover,the hash value of electronic evidence files on IPFS can be stored in the blockchain to achieve electronic evidence files can not be tampered with.Finally,in the application layer of the system,the functions of electronic deposit,electronic forensics,and judicial notarization in the judicial electronic evidence system are realized through smart contracts,and the process automation control is realized.(2)In order to solve the problem of poor privacy protection of data and user information in the judicial electronic evidence system,this paper proposes a data privacy protection scheme based on homomorphic encryption.Through this scheme,the electronic evidence files,electronic evidence information,and user information are encrypted and uploaded to the judicial electronic evidence system,and encryption technology converts data into cipher text that cannot be read without permission.However,in judicial notarization,notaries and depository users will often need to query multiple different notarization affairs or electronic evidence.Therefore,this paper proposes a confidential data query protocol that supports single/connection keyword query,multi-dimensional range query,subset query,boolean query and mixed boolean query and other expression search query modes.This paper mainly designs and implements the judicial electronic evidence system based on blockchain technology and homomorphic encryption technology.It not only protects electronic evidence from tampering,but also enhances the privacy and credibility of electronic evidence in judicial practice(electronic deposit,electronic forensics and judicial notarization). |
