Research On Identity Privacy And Data Privacy Protection Technology In Fabric

Blockchain technology has characteristics of distributed processing,blockchain storage and network-wide consensus confirmation,and provides a good solution to the problems of data storage insecurity and sharing difficulties in traditional centralized systems.The blockchain system uses a multi-party consensus validation model in decentralized mode to ensure the transparency of transaction data in the public ledger.However,since there is no single central organization in the blockchain system,if there are any questions in the privacy protection mechanisum,the consequence is disclosing user identity and transaction data to all participants,which could greatly affect the user's identity privacy and data privacy.This paper focuses on the privacy protection in the blockchain,designing and implementing a privacy protection scheme based on the Hyperledger Fabric platform from two aspects:identity privacy and data privacy.Firstly,this paper improves and implentments the identity privacy protection mechanism based on the two-level certificate security system in Hyperledaer Fabric.The improved scheme solves the low efficiency problem and the large key storage space problem of the transaction certificate key derivation scheme;It realizes the decentralized supervision mechanism between the transaction certificate authority and the regulator,which provides a more reasonable and flexible identity privacy protection program for the fabric platform.Secondly,this paper designs and implements a privacy protection mechanism of broadcast encrypted data based on hierarchical identity.According to the characteristics of Fabric's own member management structure,combined with the subset coverage framework and the hierarchical identity based encryption method,a public broadcast encrypted data based on hierarchical identity for the consortium blockchain fabric is designed.The solution realizes that only authorized nodes can see sensitive data and achieve flexible protection of private data.Thirdly,this paper designs and implements a data privacy protection mechanism based on symmetric encryption.On the core network side of the fabric,the paper designs the system smart contract that is responsible for key management and key distribution.The system smart constract achieves the goal of flexible protection of sensitive datas by using the symmetric encryption scheme to encrypt sensitive datas that are stored in the public ledger and are in the form of ciphertext.The above solutions are implemented on the Hyperledger Fabric platform.These test results show that improved schemes in identity privacy not only satisfy the non-correlation,anonymity and supervisability,but also improve the efficiency of the algorithm,reduce the key storage space,and provide a better implementation scheme while ensuring security.In the aspect of data privacy,both the broadcast encryption scheme based on hierarchical identity and the symmetric encryption scheme realize flexible data privacy protection in the same channel,so that sensitive data is stored in the public ledger in cipher text,which satisfies the requirements of high security application scenarios.