|dc.description.abstract||Vehicular ad hoc networks (VANETs) are gaining growing interest from both industry and academia. Driven by road safety requirements, the car manufacturers, transportation authorities and communications standards organizations are working together to make a quantum step in terms of vehicular information technology (IT) by equipping the vehicles with sensors, on-board processing and wireless communication modules. VANETs are composed of OBUs (On Board Units) and RSUs (Road Side Units). The communication standard used in VANETs is called DSRC (Dedicated Short Range Communication). With many essential vehicle components (radios, spectrum, standards, etc) coming into place, a lot of new applications are emerging beside road safety, which support not only safety related services, but also entertainment and mobile Internet access services.
In this study, we propose a promising commercial application for file purchasing in VANETs, where a legitimate vehicle can purchase digital files/data through a roadside unit (RSU). Due to the high mobility of the vehicles, the contact period between an RSU and a vehicle could be insufficient to download the complete file. To purchase a digital file, a vehicle purchases a permission key from a fixed RSU and then begins to download the file from the RSU via vehicle-to-RSU communications (V2R) when it is in the transmission range of the RSU. Once the vehicle in the process of downloading a file leaves the transmission range of the RSU, its neighboring vehicles with a piece of the file cooperatively help to complete the file transfer via vehicle-to-vehicle (V2V) communications. Such a commercial file purchasing system can obviously initiate a new application scenario. However, it cannot be put into practice unless the security issues, such as the user privacy, incentives for inter-vehicle cooperation, and the copyright protection for the file content are well addressed. In order to deal with these security issues, we develop a secure business framework for the file purchasing system in this study. In this framework, we preserve the user privacy by using the pseudo identity for each vehicle. We stimulate the cooperation between vehicles through micro-payment incentive mechanism and guarantee the secure payment at the same time. To protect the digital file content from unauthorized distribution, we encrypt the file content before delivery to an end user and use digital fingerprint technology to generate a unique copy for each vehicle after delivery. In a word, we propose a file purchasing application in VANETs and also develop a secure framework for this application.||en