부산대학교 도서관

To ensure that multiple data users can access the data and realize the dynamic change of user authority, this paper proposes a ciphertext updatable attribute-based searchable encryption scheme based on blockchain. Combine the blockchain with the cloud server, keyword ciphertext is stored on the blockchain, symmetric key ciphertext and data ciphertext are stored on the cloud server. When the data user wants to change the access policy or revoke the access rights of some users, this scheme uses the proxy re-encryption technology to realize attribute revocation and ciphertext update of the data requester. At the same time, the access policy is hidden, which realizes the user's privacy protection. The security analysis shows that our scheme is safe and effective. In addition, the performance analysis shows that the proposed scheme is efficient and feasible.