Research And Application Of Data Sharing Algorithm Based On Searchable Encryption

With the rapid development of cloud computing,the security search and ciphertext sharing of data have become the focus of attention.However,the search cost is extremely high by decrypting all the ciphertext and then search it.Searchable encryption technology provides cloud servers with secure search of ciphertexts.However,the existing data sharing schemes based on searchable encryption have some problems,such as data tampered on the cloud,difficulty in authorization of decryption permissions,untrustworthy search results,and key leakage.Therefore,this thesis has researched from the aspects of data integrity,access control in multi-user scenarios,and ciphertext authorization.The main research contents of this thesis are as follows:(1)A proxy re-encryption scheme supporting keyword search in Email is proposed.In order to solve the problems of secure storage and efficient sharing of messages in encrypted mail system,the scheme not only realizes ciphertext retrieval and ciphertext authorization,but also resists keyword guessing attacks and tampering attacks.In addition,symmetric encryption algorithm is adopted to improve the encryption efficiency.Searchable encryption technology is used to search encrypted mail.Email authorization is implemented by proxy re-encryption technology.Under the standard model,it is proved that the scheme satisfies the trapdoor security,keyword security,and ciphertext security.Numerical experiments show that the scheme has higher search efficiency.(2)An attribute-based search encryption scheme and support ciphertext verifiable on the blockchain is proposed.In order to solve the problem of data sharing in the multiuser scenario,the scheme achieves fine-grained data access control and ensures the confidentiality and integrity of the data simultaneously.Besides,the secure search of ciphertext is realized through searchable encryption technology and blockchain.Finegrained access control in multi-user scenarios is achieved by attribute-based encryption technology.And data integrity is ensured through ciphertext verification.At the same time,the scheme satisfies the keyword privacy security and ciphertext privacy security.Numerical experiments show that the computational efficiency of the scheme has a comparative advantage.(3)A data sharing scheme of electronic medical record based on proxy re-encryption through blockchain is proposed.In order to solve the problems of secure storage with large files and the difficulty of third-party data users sharing electronic medical record data on blockchain,the scheme not only ensures the privacy of patients,but also realizes the availability and confidentiality of data.The scheme improves encryption efficiency by symmetric encryption algorithm;and realizes the secure search of ciphertext by searchable encryption;and also realizes the ciphertext transformation by proxy reencryption technology.In addition,the patient authorizes the hospital to encrypt the electronic medical record,and third-party users to decrypt the ciphertext,thus implemented the access control to the ciphertext.At the same time,the scheme satisfies the security of keyword privacy security and ciphertext privacy security.Numerical experiments show that the scheme has higher retrieval efficiency.