Efficient and robust attribute-based encryption supporting access policy hiding in Internet of Things

The term of Internet of Things (IoT) remarkably increases the ubiquity of the internet by integrating smart object-based infrastructures. How to achieve efficient fine-grained data access control while preserving data privacy is a challenge task in the scenario of IoT. Despite ciphertext-policy attribute-based encryption (CP-ABE) can provide fine-grained data access control by allowing the specific users whose attributes match the access policy to decrypt ciphertexts. However, existing CP-ABE schemes will leak users' attribute values to the attribute authority (AA) in the phase of key generation, which poses a significant threat to users' privacy. To address this issue, we propose a new CP-ABE scheme which can successfully protect the user's attribute values against the AA based on 1-out-of-n oblivious transfer technique. In addition, we use Attribute Bloom Filter to protect the attribute type of the access policy in the ciphertext. Finally, security and efficiency evaluations show that the proposed scheme can achieve the desired security goals, while keeping comparable computation overhead.