An Efficient Privacy-Preserving Attribute-Based Encryption with Hidden Policy for Cloud Storage

Abstract

Cloud storage is one of the most widely-used storage services, because it can provide users with unlimited, scalable, low-cost and convenient resource services. When data is outsourced to cloud for storage, data security and access control are the two essential issues that need to be addressed. Attribute-based encryption (ABE) scheme can provide sufficient data security and fine-grained access control for cloud data. As more and more attention is drawn to privacy protection, privacy preservation becomes another urgent issue for cloud storage. In ABE, since the access policies are generally stored in clear text, it will lead to the disclosure of users’ privacy. Some works sacrifice computational efficiency, key length or ciphertext size for privacy concerns. To solve these problems, this paper proposes an efficient privacy-preserving attribute-based encryption scheme with hidden policy for outsourced data. Using the idea of Boolean equivalent transformation, the proposed scheme achieves fast encryption and privacy protection for both data owner and legitimate visitors. In addition, the proposed scheme can satisfy constant secret key length and reasonable size of ciphertext requirements. We also conduct theoretical security analysis, and carry out experiments to prove that the proposed scheme has good performance in terms of computation, communication and storage overheads.