Abstract:Aiming at the problems of high communication overhead between attribute authorization authority and normal users when the key is updated, high computational complexity in cloud center when the ciphertext is updated, an attribute-based ciphertext policy encryption scheme based on XOR operation is proposed to support attribute level revocation. Attribute authorization first sends the attribute name and the user ID to be revoked and the new time parameter to the cloud center. Then the cloud center uses the XOR result of the user ID and the new time parameter to perform the XOR operation with part of the ciphertext to obtain the new ciphertext. The normal user can decrypt the original ciphertext by using his own key, and further obtain the plaintext. The revoked user can decrypt the original ciphertext only by using the new key of the revoked attribute, thereby realizing attribute level revocation. The analysis shows that under the premise of ensuring system security, this scheme reduces the communication overhead between attribute authorization and users, and reduces the computing complexity in cloud center.
