Clock synchronization is a necessary feature in in-vehicle time- and safety-critical networks. The reason is that exact timing information has to be maintained in nodes, for instance for time stamps of messages that are important for safety-critical functions. A common time base has to be established at start-up time before time-sensitive data handling can begin. In vehicular applications, this clock initialization phase is only one part of tasks that have to be finished before the vehicle is fully functional. To avoid lengthy delays after vehicle ignition, this start-up phase has to be very short depending on the requirements of functions. Advanced driver assistance systems require high-bandwidth communication such as Ethernet Audio Video Bridging (AVB). Its corresponding IEEE 802.1 AS time synchronization protocol is, however, not able to guarantee fast synchronization start-up in conformance with automotive applications. This paper thus proposes and analyzes several variants of the time synchronization protocol to achieve a shorter start-up time. Simulation-based performance analysis shows that start-up times can be reduced by a factor of 40 compared to the standard IEEE 802.1 AS with the proposal, without considerably affecting synchronization error.

Nowadays embedded systems in many application areas such as automotive, medical and industrial automation are designed with well-defined hardware and software components which are not meant to be exposed for user modifications. Adding or removing components to/from such systems is not permitted and sometimes not even possible since the systems often have to be up and running in a 24/7 manner. However due to the well-known nature of these types of embedded platform configuration the effort an attacker has to invest usually is reduced. The proposed publication presents a defense in depth strategy for application specific embedded devices by combining hardware-based security enhancements of modern processors with hardware security modules.