Attribute-based encryption scheme supporting decryption outsourcing and attribute revocation in cloud storage

Aiming to reduce the user's computational overhead and tackle the attribute revocation issue, an attribute-based encryption scheme supporting decryption outsourcing and attribute revocation is proposed in this paper. The proposed scheme outsources some decryption computational tasks to a cloud server such that the computational overhead on the user is simple and constant. We also propose an efficient attribute revocation method which concentrates on the update of the ciphertexts and users' secret keys associated with the corresponding revoked attributes. Moreover, the security analysis indicates that the proposed scheme can resist collusion attacks, and ensure forward and backward secrecy. Experiment results show that our scheme is more efficient compared with other scheme in the literature.