Evaluation of Libraries and Typical Embedded Systems for ECDSA Signature Verification for Car2X Communication

Over the last decades, cars have become more and more prevalent and play an important role in our modern society. With the continuously growing number of vehicles, also the probability for road accidents and traffic congestions increases. Car2X communication in traffic infrastructure is a key enabler of many technologies yet to come, such as autonomous driving. Allowing and enabling the exchange of data from various cars and their respective environment provides amongst other possibilities - increased road safety and congestion avoidance. Several standards already exist which define the structure of messages and how they have to be signed - with elliptic curve based signatures. This signature is to be verified, ensuring authenticity and integrity so no “malicious” car can i.e. impersonate an emergency vehicle or sham an accident. However, validating an elliptic curve signature in such a field of application requires appropriate performance to ensure necessary throughput. In other words, cars and roadside equipment must be up to the task to process messages fast enough to prevent any harm, like traffic lights being switched too late or cars not being informed in time of an accident ahead. This paper shall show typical performance for out of the box embedded hardware, likely to be used for such equipment. Furthermore it will compare OpenSSL and mbedTLS regarding their performance and it will give optimization advices to maximize verification throughput.