Fine-grained data access control with attribute-hiding policy for cloud-based IoT

Ciphertext-policy attribute-based encryption (CP-ABE) is a promising approach to achieve fine-grained access control over the outsourced data in Internet of Things (IoT). However, in the existing CP-ABE schemes, the access policy is either appended to the ciphertext explicitly or only partially hidden against public visibility, which results in privacy leakage of the underlying ciphertext and potential recipients. In this paper, we propose a fine-grained data access control scheme supporting expressive access policy with fully attribute hidden for cloud-based IoT. Specifically, the attribute information is fully hidden in access policy by using randomizable technique, and a fuzzy attribute positioning mechanism based on garbled Bloom filter is developed to help the authorized recipients locate their attributes efficiently and decrypt the ciphertext successfully. Security analysis and performance evaluation demonstrate that the proposed scheme achieves effective policy privacy preservation with low storage and computation overhead. As a result, no valuable attribute information in the access policy will be disclosed to the unauthorized recipients. (C) 2019 Elsevier B.V. All rights reserved.