Security-Aware Mapping and Scheduling with Hardware Co-Processors for FlexRay-Based Distributed Embedded Systems

Automotive in-vehicle systems are distributed systems consisting of multiple ECUs (Electronic Control Units) interconnected with a broadcast network such as FlexRay. Message authentication is an effective mechanism to prevent attackers from injecting malicious messages into the network. In order to reduce timing interference of message authentication operations on application tasks, hardware coprocessors in the form of either FPGA or ASIC are adopted to offload computation-intensive cryptographic algorithms from the ECU. However, it may not be feasible or desirable to equip every ECU with a hardware coprocessor, as modern vehicles can contain more than one hundred ECUs, and the automotive industry is cost-sensitive. In this paper, we consider the problem of mapping an application task graph onto a FlexRay-based distributed hardware platform, to meet security and deadline requirements while minimizing the number of hardware coprocessors needed in the system. We present a Mixed Integer Linear Programming (MILP) formulation, a divide-and-conquer heuristic algorithm, and a Simulated Annealing algorithm. We evaluate the algorithms with industrial case studies.