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A Privacy-Preserving and Verifiable Querying Scheme in Vehicular Fog Data Dissemination

Vehicular fog has attracted considerable attention recently, as the densely deployed fog devices are in proximity to vehicular end-users, and they are particularly suitable for the latency-sensitive and location-aware vehicular services. In this paper, we propose a secure querying scheme in vehicular fog data dissemination, in which the roadside units (RSUs) act as fog storage devices to cache data at network edge and disseminate data upon querying. To disrupt the association between a specific data request and its origin vehicle, the proposed scheme exploits an invertible matrix to structure multiple data requests from different vehicles, and aggregates the ciphertexts of data requests at the RSU side with the homomorphic Paillier cryptosystem. Meanwhile, given the invertible matrix and decryption result, the RSU can recover each individual data request without identifying its origin vehicle. In addition, the RSU can verify the correctness of the recovered data requests with an identity-based batch verification scheme. Through security analysis, we demonstrate that the proposed scheme can achieve the security goals of unlinkability, confidentiality, and verifiability. Performance evaluations are also conducted, in which the obtained results show that the proposed scheme can be adaptive to the fluctuating number of the data querying vehicles, and significantly reduce the computation complexity and communication overhead.