Analysis of Security Overhead in Broadcast V2V Communications

This paper concerns security issues for broadcast vehicle to vehicle (V2V) messages carrying vehicle status information (location, heading, speed, etc.). These are often consumed by safety-related applications that e.g. augment situational awareness, issue alerts, recommend courses of action, and even trigger autonomous action. Consequently, the messages need to be both trustworthy and timely. We explore the impact of authenticity and integrity protection mechanisms on message latency using a model based on queuing theory. In conditions of high traffic density such as found in busy city centres, even the latency requirement of 100 ms for first generation V2V applications was found to be challenging. Our main objective was to compare the performance overhead of the standard, PKC-based, message authenticity and integrity protection mechanism with that of an alternative scheme, TESLA, which uses symmetric-key cryptography combine with hash chains. This type of scheme has been dismissed in the past due to supposed high latency, but we found that in high traffic density conditions it outperformed the PKC-based scheme. without invoking congestion management measures. Perhaps the most significant observation from a security perspective is that denial of service attacks appear very easy to carry out and hard to defend against. This merits attention from the research and practitioner communities and is a topic we intend to address in the future.