Secure, Robust and Flexible Cooperative Downloading Scheme for Highway VANETs

The increasing popularity of smart vehicles and vehicular ad hoc networks (VANETs) has reinforced the importance of Internet connectivity. However, existing solutions (e.g., those based on cooperative downloading via drive-thru Internet) have a number of limitations, partly due to the challenges in selecting reliable proxy vehicles in a fast moving driving situation, and balancing between flexible data downloading and achieving strong security. Therefore, in this paper we propose a secure, robust and flexible cooperative downloading scheme based on our reputation based selection mechanism and ordered signatures. Using the reputation based selection mechanism, only vehicles with the highest expected downloading capacities will be selected as proxy vehicles. This helps us to avoid selecting less reliable proxy vehicles. The flexible data downloading is achieved by dividing a file into small blocks so that a proxy vehicle can flexibly vary the file / data download, for example based on existing condition. Our scheme also achieves strong security, in the sense that it realizes traditional authentication, privacy preservation and message confidentiality, as well as a newly introduced security requirement (i.e., process authentication: authenticates the order of file blocks and the order of the assisting vehicles using ordered signatures).