Security Assurance Cases (SAC) are structured arguments and evidence bodies used to reason about security of a certain system. SACs are gaining focus in the automotive domain as the needs for security assurance are growing. In this study, we present an approach for creating SAC. The approach is inspired by the upcoming security standards ISO/SAE-21434 as well as the internal needs of automotive Original Equipment Manufacturers (OEMs). We created the approach by extracting relevant requirements from ISO/SAE-21434 and illustrated it using an example case of the head lamp items provided in the standard. We found that the approach is applicable and helps to satisfy the requirements for security assurance in the standard as well as the internal compliance needs in an automotive OEM.
