## 3 Vcc-Ssf
### Analysis of VCC-SSF  
In this section, we analyze VCC-SSF to compare with methods that are proposed in previous studies based on security concerns--Confidentiality, Integrity, Availability, and Privacy Protection in the VCC environment. The security comparison is shown in Table 5. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Classification**} & **[PERSON] _et al._** & **[PERSON] _et al._** & **[PERSON] _et al._** & **[PERSON] and [PERSON]** & **[PERSON] _et al._** & \multirow{2}{*}{**VCC-SSF**} \\  & **[12]** & **[17]** & **[18]** & **[21]** & **[22]** & \\ \hline Confidentiality & \(\Delta\) & O & X & O & O & O \\ Integrity & \(\Delta\) & O & X & O & X & O \\ Availability & X & X & X & X & X & \(\Delta\) \\ Privacy & \(\Delta\) & O & X & O & O & \(\Delta\) \\ Protection & & & & & & \\ \hline \hline \end{tabular} (O: strong, \(\Delta\): medium, X: weak).  
\end{table} 
Table 5: Security comparison. **Confidentiality:** Data are generated through many sensors in the vehicle. In addition, private identification information, payment information, location information, _etc._ are provided from or sent to the traffic infrastructure. In this case, only permitted vehicles should be able to receive services, and user access to important information should be separated through access control. In addition, the information should be encrypted to prevent exposure to external users. The VCC-SSF system proposed in this paper can separate users via role-based access control inside and outside the vehicle along with the vehicle authentication to control information usage. In addition, the data sent from inside or outside the vehicle is encrypted to defend against tapping, falsification, or other malicious activities. The framework proposed in [17] comprises context-aware vehicular security mechanisms (CVSMs), and collects data from sensors. The information is protected through encryption, authentication, and access control. The system proposed in [12] protects location or map information, but the protection of other important information is limited. The framework proposed in [21] protects vehicle speed, location, and personal information based on GeoLock. The framework proposed in [22] uses hashed ElGamal encryption to encrypt vehicle location and personal information. The framework in [18] does not mention any technology to provide confidentiality. **Integrity:** Integrity should be provided for private identification information, payment information, and location information. Just as for important information extortion, integrity invasion also causes financial damage to the user. VCC-SSF disables the identification of the vehicle or the user by hashing the unique information or ID of the object. In addition, integrity is provided for important information such as Personal Information, Payment Information, _etc._, through the hash function. However, in the framework in [12], the information for which data integrity is provided is limited. Integrity is applied only to geographical or location information, and details for other information such as personal identification or payment is limited. The framework in [21] uses beacons to provide the integrity. A beacon includes the current time, location, and speed, and it uses HMAC to periodically transmit it. The frameworks in [17,22] are undergoing development for integrity protection. **Availability:** In the VCC environment, it is important to provide services without network disconnection. Because of the characteristics of wireless network environments, attacks that degrade availability such as Denial of Service (DoS), Distributed Denial of Service (DDoS), or black hole attacks may occur. VCC-SSF only provides services between the vehicle and infrastructure and between vehicles to permitted vehicles in order to defend against these attacks. The number of authentication attempts is limited to block access attempts from external malicious users. In cases of the existing frameworks [12,17,18,21,22], studies on attacks against availability are undergoing.