Research On Data Security Sharing System Based On Blockchain

In the existing Internet environment,data sharing relying on third-party information platforms is accompanied by the direct or indirect disclosure of users' privacy.Data is also easy to be stolen or tampered,or the management of role is too poor to cause the problem of data access beyond authority.Blockchain as a decentralized distributed ledger technol-ogy,can effectively guarantee the safe flow of data due to its immutable characteristic.However,although existing data sharing schemes based blockchain guarantee that data cannot be tampered with,the excessive transparency of transaction will still lead to data leakage.And attackers can analyze the correlation between different transactions easily.Secondly,most of the data sharing schemes based on public blockchain generally have the problem of low transaction efficiency and cannot guarantee the honesty of participants.This thesis aims at the problems in the blockchain network,such as the inability to guarantee the honesty of participating nodes,unclear data access rights of participating users and low transaction efficiency in the public blockchain.This thesis is based on the consortium blockchain,attribute encryption method and the trusted execution envi-ronment construction as the main research contents,will be based on Ciphertext-Policy Attribute-Based Encryption and construction of the trusted execution environment based on container technology combined with consortium blockchain.A set of data security sharing scheme of on-chain and off-chain collaboration is proposed.The main research contents are as follows:1.An on-chain data sharing scheme(DSOC)based on consortium blockchain is proposed.In this scheme,the traditional Ciphertext-Policy Attribute-Based Encryption method is improved,the distribution and storage form of key are optimized,and the access control of blockchain users is realized.Meanwhile,a new block structure is designed with this on-chain access control method,the characteristics of the consortium blockchain and the relevant characteristics of the data sharing scenario.This solution solves the problem that the honesty of participating nodes cannot be guaranteed and the users' access rights to data are unclear in the blockchain network.It also enhances the security of data sharing.2.A lightweight trusted execution environment off the chain based on container technology is proposed,and the association mapping between the user identity inside the container and the identity on the blockchain platform is completed based on smart contract.At the same time,the execution process inside the container is recorded by the way of recording screen traceability,and the data and recording screen results are re-chained at the time of container destruction to ensure the synergy between the on-chain and off-chain.The specific operation of the data file is carried out off the chain,which solves the problem of low transaction efficiency caused by direct operation of the data file on the chain.It increases the efficiency of the transaction.Based on the above research contents,the experimental simulation based on the un-derlying consortium blockchain platform has been done.The feasibility is demonstrated through the prototype implement.This thesis interprets the functions of the whole data sharing system in an engineering way,and makes a horizontal comparison with the rele-vant schemes in terms of data trading and data security,in order to illustrate the advantages of the sharing system proposed in this thesis and the other contents that needs to be im-proved.