## 4 Proposed Test Simulation
### Configuration of Environment Linked to Virtual Machine  
Since each node implemented in a typical commercial V2X communication simulation exists only within the simulation, it is not connected to the external ITS infrastructure network, unlike the ITS components in the real-world environment [34; 35]. Furthermore, it can implement only virtual software nodes that do not include operating systems (OS) and security systems and do not have the characteristics of the hardware. In this section, we \begin{table}
\begin{tabular}{c c c c c c} \hline  & **[PERSON] et al.**[28] & \begin{tabular}{c} **Veins** \\ **(with VeReMi)**[32] \\ \end{tabular} & \begin{tabular}{c} **Sprient** \\ **V2X Test [33]** \\ \end{tabular} & \
\begin{tabular}{c} **Keysight** \\ **Call Simulator**[34] \\ \end{tabular} &
\begin{tabular}{c} **Vector** \\ **CANoe**[35] \\ \end{tabular} \\ \hline
**Target** & \begin{tabular}{c} V2X simulation research \\ Validation of \\ message \\ interoperability \\ \end{tabular} & \begin{tabular}{c} Commercial evaluation tool \\ Simulation \\ traffic and message \\ validation \\ \end{tabular} & Validation test & Device test & Device test \\  & \begin{tabular}{c} \(\triangle\) \\ (Only \\ V2X message) \\ \end{tabular} & \begin{tabular}{c} O \\ (Provided \\ as a module) \\ \end{tabular} & \
\begin{tabular}{c} O \\ (Call simulator) \\ \end{tabular} &
\begin{tabular}{c} O \\ (V2X messages \\ full stack) \\ \end{tabular} \\
**Security** & \begin{tabular}{c} \(\triangle\) \\ (Only message \\ conformance) \\ \end{tabular} & \begin{tabular}{c} \(\triangle\) \\ (Only for \\ specified data) \\ \end{tabular} & \
\begin{tabular}{c} \(\triangle\) \\ (Only standard) \\ conformance) \\ \end{tabular} &
\begin{tabular}{c} N \\ (Feature \\ implementation \\ required) \\ \end{tabular} \\
\begin{tabular}{c} O \\ (Can receive \\ external device \\ message) \\ \end{tabular} \\
**Application** & \begin{tabular}{c} N \\ (Only check \\ message \\ \end{tabular} & \begin{tabular}{c} \(\triangle\) \\ (Only handle \\ ITS application) \\ \end{tabular} & \
\begin{tabular}{c} \(\triangle\) \\ (Only handle \\ message for test) \\ \end{tabular} &
\begin{tabular}{c} N \\ (Can implement \\ send/receive \\ messages) \\ \end{tabular} \\
**Creation** &
\begin{tabular}{c} \\ (Provide \\ implementation \\ environment \\ only) \\ \end{tabular} \\ \hline \end{tabular}
\end{table} 
Table 2: Comparison of requirements for V2X simulation and testing tools for security evaluation scenario development. will configure a simulation environment closer to the real-world environment by linking the virtual machine to the software nodes implemented within the simulation to assign the OS and hardware characteristics to the nodes and connect them to the external network. Through this, the performance of the security functions, such as an intrusion detection system (IDS), can be tested regardless of the programming language of the simulation equipment by sending and receiving data. As shown in Figure 7, by linking the simulation nodes and the virtual machine, we can create an environment to test attack scenarios in which attacks started at vulnerabilities in the OS, network, and protocols of actual ITS components reaching and affecting the V2X network. Since the simulation test environment proposed in this paper uses a virtual machine, the OS used by each part and system can be freely configured. Moreover, the virtual machine can be linked to multiple simulation nodes according to the tested environment configuration and scenario to configure them as 1:n or n:n, instead of 1:1. The virtual machine-linked security testing method proposed in this study must use a simulation to implement a handler of transmitted/received messages of the nodes and virtual machine. The simulation used for implementation in this paper used Vector CANoe Pro Option.Car2X, which can directly implement the handler of the transmitted/received messages of the simulation nodes. Figure 8 shows the vehicle and RSU nodes implemented by CANoe Pro Option.Car2X.