Threshold Cryptography-Based Secure Vehicle-to-Everything (V2X) Communication in 5G-Enabled Intelligent Transportation Systems  
[PERSON]  
1 Faculty of Science, Engineering and Computing, Kingston University London, London KT1 2 EE, UK;  
1 [EMAIL_ADDRESS] (N.W.) [PERSON]  
1 Faculty of Science, Engineering and Computing, Kingston University London, London KT1 2 EE, UK;  
1 [EMAIL_ADDRESS] (N.W.) [PERSON]  
2 Cybersecurity and Information Networks Centre (CINC), Cardiff School of Technologies,  
A V2X network consists of vehicles fitted with wireless communication devices called onboard units (OBUs). Each OBU contains a hardware security module, a tamper-proof device for storing security information. The OBU on a vehicle communicates with a roadside unit (RSU), roadside users (RU) such as pedestrians and cyclists, as well as other vehicles (OBUs) [3]. Earlier VANET networks were proposed ad hoc Wi-Fi networks and were standardized in IEEE 802.11p [4]. This standard enables mobile nodes to communicate in a dynamic topology with intermittent connection, supporting non-line of sight. Although this technology can be deployed with the minimum investment, it lacks scalability, quality of service (QoS), and has limited coverage due to short radio changes [5]. Fifth generation network-based V2X is promised to provide low latency, high reliability, and high bandwidth. Moreover, 5G-based V2X can operate as a cellular-based communication [6] where V2X devices acting as user equipment (UE) communicate with the 5G Next Generation NodeB (gNB) for uplink and downlink connectivity. Furthermore, 5G Core can provide authentication and network resource management, while cloud hosted V2X applications can provide V2X specific functionality. On the other hand, Device-to-Device communication (D2D), defined in 3 GPP side-link [7], allows two UE's (two vehicles or vehicle to RSU) to communicate without passing data through the 5G core network. Security is a critical challenge in V2X communication. The data are transmitted over insecure wireless channels. They can be readily intercepted or tampered with by an attacker, thereby resulting in severe threats to the safety and privacy of vehicles, e.g., illegal tracking or remote hijacking. Further, they are susceptible to unauthorized vehicles sending falsified data to disrupt the standard transmission of data and providing incorrect messages to cause traffic mismanagement or even a severe traffic accident. Thus, improving the security and integrity of vehicle data sharing has become a primary focus for researchers. The IEEE 802.11p-based network can use IEEE P1609.2 [8], which defines a certificate-based cryptographic algorithm to secure transaction messages between two entities and broadcast messages that do not direct to a particular entity. On the other hand, the 5G-based V2X can use the existing authentication mechanism of the 5G network [9; 10; 11]. This generally addresses physical layer to network-layer security. However, there is still a gap in V2X application layer security and privacy requirements. At any given time, a V2X network can have vehicles manufactured by different manufacturers and even registered in different countries or jurisdictions. While the RSU part of V2X remains static, vehicles are continuously joining and leaving the network. Especially in V2V communication, depending on their speed and direction of travel, they may be in the communication range for a few seconds. Therefore, it is required to create a trusting relationship between vehicles quickly. Data privacy is of utmost importance in V2X data sharing, as vehicles must share accurate information about vehicle and road conditions while maintaining anonymity. Additionally, different countries may have varying data privacy laws.