A Delegable Inner Product Predicate Encryption Scheme for Secure Data Sharing in the Internet of Vehicles

With the rapid development of the Internet of Vehicles (IoV), data exchange among vehicles, roadside units, and cloud platforms has become increasingly frequent. Achieving efficient and real-time cross-domain data sharing while ensuring data security and privacy has emerged as a critical challenge. Traditional encryption schemes often suffer from low efficiency and high computational overhead in ciphertext sharing and key management, making them unsuitable for resource-constrained environments such as IoV. To address these issues, this paper presents an inner product predicate encryption scheme with identity delegation functionality. By incorporating an identity delegation mechanism, the proposed scheme offloads complex key generation and partial decryption computations to the cloud, thereby significantly reducing the computational burden on end devices. Moreover, a constant ciphertext size encryption process is designed to avoid the ciphertext expansion that typically occurs with increasing identity levels or vector dimensions. In addition, a hash-based address tracking and revocation mechanism is employed to achieve efficient and dynamic permission management. Both theoretical security analysis and computational efficiency evaluations indicate that the proposed scheme outperforms existing schemes in the key generation, encryption, and decryption phases while ensuring security and privacy, particularly when processing high-dimensional data. Experimental results further demonstrate the practical application potential of the scheme in real-time, resource-constrained environments such as IoV.