Biblio

The traditional ciphertext-policy attribute-based encryption (CP-ABE) has the problems of poor security of key distribution by a single attribute authorization center and too much calculation on the client in the process of encryption and decryption. A CP-ABE scheme that can outsource encryption and decryption and support multi-authorization centers is introduced to solve the above two problems. In the key generation stage, the user's private key is generated by the attribute authorization center and the key generation center jointly executing the two-party secure computing protocol; In the encryption and decryption stage, the cloud encryption server and cloud storage server are used to handle most of the computing work. Security proof and performance analysis show that the scheme not only can effectively make up for the defect of all key leakage when the attribute authorization center is broken, but also can enhance the security of the system; Moreover, after using the cloud server to process data, users only need to perform a simple calculation on the client to complete encryption or decryption, thus reducing the user's computing workload.