## 5 Discussion
### Challenges of Perceived Ease of Use in Cybersecurity Maintenance
Cars are full of individual components that are very different from each other (such as sensors or actuators), and in terms of electronic components, they are controlled by ECUs. Cars have around 100 ECUs (depending on the features and technology that they carry), although now they are changing to more modular and'software-oriented' vehicles and are reducing the ECUs and centralizing the processing and controls of their features. There are many types of ECUs (see Table 9), which are connected to actuators and sensors that will read /actuate depending on the input. ECUs will also be connected to a vehicle bus network (CAN/LIN/FlexRay/Ethernet) (A vehicle bus network is a specialized internal communications network that interconnects components inside the vehicle. Types of buses that can be found on vehicles are CAN (controlled area network), LIN (local interconnected network), FlexRay (faster than CAN but more expensive), Ethernet, etc. (see, for example, [PERSON] et al. [66])) [3; 16]. Therefore, as shown, ECUs are very different, and it also has to be added that ECUs can be in a closed circuit (closed system) or an open connection (open system, interacting with external devices to the vehicle) (see, for example [3]). Thus, thinking about the types of requirements, measures and controls to put in place to secure ECUs is a real problem and challenge for OEMs and suppliers. \begin{table}
\begin{tabular}{c c} \hline \hline
**Name** & **Description** \\ \hline Engine Control Module (ECM) & Controls and monitors a series of actuators and sensors associated with the ICE (Internal Combustion Engine) to ensure optimal engine performance \\ \hline Powertrain Control Module (PCM) & This is a combined engine and transmission control unit that will provide management and correct function of the engine and transmission from one control unit. \\ \hline Telematics Control Module (TCM) & The TCU collects telemetry data from the vehicle (location, speed, engine data, battery data. diagnostics, etc.), and wirelessly reports these data. \\ \hline Electronic Brake Control & Monitors the sensors and actuators of the braking systems and can activate the ABS (Anti-lock Braking System) or traction control system when necessary. \\ \hline Battery Control Module (BCM) & Monitors the state of the battery and measured current, voltage and temperature values to evaluate the state of the battery and to determine actions on the on-board electrical system \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Types of ECUs. Another challenge stemming from the complexity of applying cybersecurity is the vehicle's lifecycle. In the manufacturing of a vehicle, a lot of parties intervene in its development, from suppliers to engineers and designers, making room for cascading cybersecurity requirements very small, as these should not interfere with the requirements of other stakeholders. As mentioned before, the process of developing a vehicle is very long (it may take two or three years) with very well-defined gateways. Studies (see, for example, [4; 61]) have shown how difficult it is to map or include security in those processes, especially in secure software development. The next challenge that complicates cybersecurity in vehicles is the growing connectivity. Increased connectivity in vehicles offers significant advantages, such as traffic management, vehicle software updates, and integration with other devices, such as smartphones, providing a personalized and streamlined experience. In the context of the Internet of Things and smart devices, vehicles are intensifying their connectivity [16; 33; 67]. Thus, concepts such as V2V, V2I, and V2X, which refer to different types of communication systems in the context of connected vehicles, become increasingly important [6]. These communication technologies are fundamental for the development of connected and autonomous vehicles, as they enhance safety, efficiency, and overall driving experience by enabling vehicles to interact with each other and with the surrounding environment [67].