摘要：In order to improve the efficiency of attribute based encryption, according to the work of Li etal. [17] , a new technique is adopted to implement the revocation of attribute-based encryption. Based on the work of Green etal.[16], a ciphertext attribute based encryption (CP-ABE) scheme with outsourced revocation and decryption simultaneously is proposed. After outsourcing complex computation in decryption and key update operation to decryption cloud service provider (D-CSP) and key update cloud service provider (KU-CSP), the proposed construction not only decreases the decryption computation of users, but also not requires the attribute authority to online all the time to provide key update operation for users, which greatly relieves the burden of users and attribute authority.
