I. Introduction
After centuries of development in the automobile industry, vehicle construction has evolved from pure mechanical-based handmade vehicles to microchip-based intelligent electric vehicles. In particular, in recent years, with the urgency of microchips and various types of sensors, great attention has been paid to software-defined vehicles and the intra-vehicle network (IVN). Universally, in a modern electric vehicle IVN, more than one bus (and perhaps more than one type) are combined by a central gateway to divide and conquer. Different types of IVN bus systems, such as the Controller Area Network (CAN), FlexRay, Local Interconnect Network (LIN), and Media Oriented System Transport (MOST), have been designed to perform specific functions during vehicle operation. For example, several CAN buses are deployed to support essential functions for Engine Control Module, Supplemental Restraint System, Electronic Stability Program, and Anti-lock Brake System (ABS); a LIN bus is deployed to control Front Lights, Air Condition, and Door Locks; a MOST bus is used to provide Navigator and Media Entertainment System. Among the intra-vehicle bus systems, CAN is the most well-known because of its strong robustness and well efficiency with low cost. Generally, in a CAN bus system, Electronic Control Units (ECUs) are connected together and could share CAN frames with each other. To be specific, the ECUs together with sensors or actuators act as basic units to collect or process data such as acceleration, speed, temperature, etc. After being primarily processed, the data is encapsulated into a CAN frame and is broadcasted on the CAN bus. The rest of the ECUs can accept or discard the frames broadcasted on the bus.