A B S T R A C TVehicular Ad Hoc Networking (VANET) technology is, at it's core, the simple idea of outfitting vehicles with wireless data communication equipment for automatic information exchange. This technology is expected to serve as a foundation for a set of novel safety, automation, and infotainment applications. The most prominent among these applications are expected to be driver assistance systems which also support advanced levels of automated driving. These applications stand to benefit from enhanced situational awareness, which is made possible through the cooperative exchange of information about environmental influences and the presence and condition of surrounding vehicles.Wireless networking technology and networking in general are well understood domains in computer science. However, the context of connected vehicles and the associated requirements and communication patterns imposes a set of unique challenges, which require solutions that differ from established networking practices. The susceptibility of wireless communication to packet loss and the very high mobility of vehicular communication nodes make VANET technology extremely volatile. At the same time the usage in safety critical applications demands very low latency and high availability of the communication infrastructure for frequent information exchange. And on top of these challenges security and privacy need taken into account in the design of the overall communication infrastructure. Classic solutions for stable networks cannot provide optimal performance characteristics under these conditions. The focus of this work is specifically on vehicle-to-vehicle technology (V2V), which is a subset of the more general vehicle-to-anything (V2X) topic. This subset of VANET is concerned with the direct information exchange among vehicles without the involvement of additional infrastructure, which may or may not be available to vehicles which driving. Direct V2V communication is expected to always be available between vehicle within a safety critical range. Therefore, this communication path is expected to be used to enable the most safety critical applications.The scalability of security solutions for vehicular communication remains an untested aspect of ongoing efforts to bring VANET technology to the market on a larger scale. Filed operational test projects have started to trial VANET deployments to investigate, but penetration rates are too low to allow for realistic extrapolations of future scalability problems. This dissertations contributes to the research efforts that support the development of secure vehicular communication techv nology through investigations of attributes and solutions for scalable security for V2V broadcast communication.Part II reviews security requirements and provides detailed quantifications of performance requirements for security in V2V broadcast communication. These requirements define the solution space for applicable broadcast authentication techniques. Additionally, the review of achievable security and pr...