An Automotive Signal-Layer Security and Trust-Boundary Identification Approach

:An important trend in the automotive domain is to adapt established functional safety processes and methods for security engi- neering. Although functional safety and cyber-security engineering have a considerable overlap, the trend of adapting methods from one domain to the other is often challenged by non-domain experts. Just as safety became a critical part of the development in the late 20th century, modern vehicles are now required to become resilient against cyber-attacks. As vehicle providers gear up for this challenge, they can capitalize on experiences from many other domains, but must also face several unique challenges. Such as, that cyber-security engineering will now join reliability and safety as a cornerstone for success in the automotive industry and approaches need to be integrated into the mainly safety oriented development lifecycle of the domain. The recently released SAE J3061 guidebook for cyber-physical vehicle systems focus on designing cyber-security aware systems in close relation to the automotive safety standard ISO 26262.The key contribution of this paper is to analyse a method to identify attack vectors on complex automotive systems via signal interfaces and propose a security classification scheme and protection mechanisms on signal layer. To that aim, the hardware- software interface (HSI), a central development artefact of the ISO 26262 functional safety development process, is used and extended to support the cyber-security engineering process and provide cyber-security countermeasures on signal layer.