Privacy-preserving decentralized ciphertext-policy attribute-based encryption with fully hidden access structure

Abstract

To make multi-authority ABE schemes collusion-resistant, a user in the system must be tied with a globally verifiable identifier GID. The drawback of this approach is that it compromises the user's privacy. Malicious authorities can collect user's attributes by tracing the user GID, thus compromises the privacy of the user. The other privacy concern is access structures that sent along with ciphertext in traditional CP-ABE schemes may have sensitive information. In this paper, we propose a multi-authority ABE scheme with fully hidden access structure that authorities can get nothing about user GID when generating and issuing user private keys and access structures are hidden to receivers. We prove the security of our scheme under a standard complexity assumption of decisional bilinear Diffie-Hellman (DBDH) assumption. The access structure we used in our scheme is AND, OR gates on multi-valued attributes. © Springer International Publishing 2013.