Efficient, Verifiable and Privacy Preserving Decentralized Attribute-Based Encryption for Mobile Cloud Computing

In order to realize data sharing in mobile cloud computing, decentralized attribute-based encryption (ABE) has been widely concerned. However, the existing ABE schemes are full of flaws. First, the main drawback of ABE is that the computation cost of encryption and decryption are expensive. Second, the existing ABE schemes are inapplicable due to the inefficiency of user revocation. Besides, in a decentralized ABE scheme, a user's private keys must be tied to the global identifier (GID) to resist collusion attack, however, it will compromise the user's privacy. To deal with these problems, we proposed an efficient decentralized ABE scheme via using the offline/online encryption and the verifiable outsource decryption concepts. Meanwhile, we proposed an anonymous key issuing protocol to achieve privacy preserving. Security analysis and experimental result shows that our scheme is secure and significantly reduce the computation cost for both encryption and decryption.