An efficient signcryption for data access control in cloud computing

Data storage is one of main services in cloud computing. How to ensure the confidentiality and authorized access of data is the central issue of data storage. In this paper, we propose a novel data access control scheme that can simultaneously achieve confidentiality and authentication for cloud computing. In this scheme, users store encrypted data in the cloud. When a user wants to access the data, the data owner delegates the cloud to re-encrypt the data and only the authorized user can decrypt the data. The cloud can not get any plaintext information about the data. In addition, the authorized user can verify the integrity and authentication of the data. We realize the data access control scheme by proposing an identity-based signcryption (IBSC) scheme with proxy re-encryption. We prove that the IBSC scheme has the indistinguishability against adaptive chosen ciphertext attack under the decisional bilinear Diffie-Hellman problem and existential unforgeability against adaptive chosen message attack under the computational Diffie-Hellman problem in the random oracle model.