Multi-Authority Ciphertext-Policy Attribute-based Encryption with Hidden Policy for Securing Internet-of-Vehicles

With the rapid development of the Internet-of-Vehicles (IoV) technologies, security and privacy issues associated with IoV data sharing have become increasingly prominent. Although attribute-based encryption (ABE) schemes offer effective solutions to these problems, the prevalent single-point failure vulnerabilities and risks of user privacy leakage in existing ABE schemes must be addressed. To this end, an original hidden policy scheme based on multi-authority ciphertext policy ABE is proposed. This scheme validates users by introducing multiple attribute authorities and generating intermediate attribute keys, effectively dispersing single-point performance pressure. Simultaneously, partial policy-hiding techniques are developed to ensure efficient system operation while protecting user privacy. Furthermore, this scheme introduces a central authority to track potentially malicious attribute authorities, preventing them from continuously generating incorrect attribute intermediate keys, thereby maintaining the overall security of the system. Additionally, by updating and revoking attribute versions, a flexible attribute revocation mechanism is achieved to further enhance system flexibility. Through in-depth security and performance analyses, the scheme is proven to be both secure and efficient for securing IoV.