Research On Cloud Data Security Sharing Encryption Scheme Based Blockchain And Attribute Based Encryption

With the development of network technology and the popularity of terminal devices,massive resources have a great demand for storage space.In order to save local storage space,more and more data are outsourced to ECS for storage and sharing.However,ECS is a semi trusted entity,which will always spy on data information intentionally or unintentionally,and data management is facing severe challenges.In order to ensure the security of data,it is necessary to encrypt the data before storage,and ensure the integrity and accuracy of data during data sharing.The existing solutions still have the following problems:first,due to the limited computing power and resource processing capacity of ECs,the processing and storage of massive data will reduce the storage efficiency of the system.Second,the sharing of encrypted data will also cause transmission delay,low efficiency and poor service quality of end data users.Thirdly,ECS is a centralized entity.Once a single ECS is unavailable,the whole cloud storage system will have security risks,resulting in data loss.Based on the above problems,this paper proposes a decentralized data storage and secure sharing scheme based on attribute based encryption in combination with blockchain and IPFS technology.The main work of this paper is as follows:(1)An attribute based searchable encryption scheme supporting multiple keywords on the blockchain is proposed.The scheme uses multi keyword searchable encryption technology to realize the effective search of encrypted data,uses attribute based encryption technology to realize the fine-grained access control of encrypted data,and combines the blockchain to maintain the fairness between users and data owners,so as to reduce the storage cost of IPFS system.Under the security model,it is proved that the scheme can ensure keyword security and trap door security.Numerical experiments show that the scheme has high efficiency in keyword ciphertext generation stage and keyword search stage.(2)An efficient attribute revocable attribute based encryption scheme is proposed.The revocation of user attributes is realized by proxy re encryption technology.The and gate,or gate and threshold operation of the expression of access structure are realized by using Chinese Remainder Theorem and tree access structure.At the same time,the length of key and ciphertext is shortened.The revocation request is processed by intelligent contract,which improves the efficiency of the scheme.Under the security model,the proof scheme can ensure keyword security and revocation security.Numerical experiments show that the scheme has high efficiency in the attribute revocation stage.To sum up,the cloud data security sharing scheme based on blockchain and attribute based encryption designed in this paper combines data management,blockchain data protection and IPFS technology,which has the advantages of strong tamper resistance,high security and low cost.The security and efficiency of the resource data sharing system are enhanced through blockchain technology and IPFS technology,which is expected to promote the further development of resource data sharing.