Privacy Sustaining Constant Length Ciphertext-Policy Attribute-Based Broadcast Encryption

Abstract

Cryptography-based data distribution is an advanced technique used to control the access of broadcasting data over cloud storage environment. A ciphertext-policy attribute-based encryption (CP-ABE) technique encrypts the data in the cloud scenario, and the data is accessed only when the decryptor satisfies the encrypted access scheme. In this technique, each user is assigned with attributes in the recovering key, and the authorized user is allowed to process the data when their attributes match the keywords embedded in the access policy. Existing techniques used for providing privacy partially hides the access policy in the ciphertext. Therefore, it may leak private information about the user; also, the size of ciphertext is linear with respect to the sum of attributes. In this paper, an efficient privacy sustaining ciphertext-policy attribute-based broadcast encryption technique with AND gate and wildcard access scheme is proposed. The proposed technique provides security proof to sensitive data broadcasted over unsecured channel with hidden access policy. Further, this technique will achieve constant length ciphertext for any number of attributes. Moreover, the communication overhead and the computation complexity are significantly reduced in the proposed method.