A Lightweight Privacy-Preserving Cache Sharing Scheme With Label Protection for Vehicular Networks

The growing Internet of Vehicles (IoV) requires efficient edge data management, where collaborative cache sharing between Roadside Units (RSU) and vehicles is crucial for reducing latency in applications like real-time navigation and collision avoidance. However, direct sharing of sensitive data such as vehicle locations and requests introduces serious privacy risks. To address this, we propose a lightweight privacy-preserving cache sharing scheme with label protection for vehicular networks. We first design an Oblivious Homomorphic XOR-PRF (Ohx-PRF) that employs key pre-distribution and homomorphic aggregation to eliminate oblivious transfer interactions. Building on this, we construct a non-interactive labeled delegated multi-party private set intersection (LDMPSI) protocol, where each data subset carries a classification label. Finally, we introduce a cache sharing scheme based on LDMPSI that uses efficient multi-point OPRF with only symmetric cryptography. By delegating computations to servers and processing data and labels in ciphertext, RSU can identify and store frequently requested content with minimal overhead. Formal analysis proves the proposed protocol and scheme are secure under the semi-honest model. Experiments show our scheme achieves over 85% cache hit rate, while LDMPSI reduces total runtime by 79% and communication overhead by over 80% compared to existing protocols, enhancing resource utilization and response capabilities in vehicular networks without compromising privacy.