## 3 System Model
### Join the Network
Typically, V2X applications share information with neighbors, for example, traffic information and road conditions using message broadcast. In addition, V2X multi-hop routing protocols use the broadcast message to discover its one-hop neighbors. These messages are generated regularly and need to be delivered and consumed quickly. Therefore, we propose that broadcast messages be encrypted with a partial share received from the local TA with ElGalmal encryption. The receiving node can then compute the corresponding decryption key and decrypt the message with ElGalmal decryption. According to Figure 8,

Figure 4:1 Comparison of encryption and decryption time. using only one TA reduces the calculation time to 10 ms. We also propose for the node to cache the calculated public key so that subsequential broadcast messages from the same source can be decrypted quickly. ## 6 Conclusions and Future Work

The performance evaluations presented in this research demonstrate that the proposed V2X communication system achieves efficient and secure communication with optimal parameter settings. Specifically, larger private key sizes, higher threshold values, server verification, and computational optimization techniques can significantly reduce the time required for vehicles to join the V2X network. Additionally, improvements to the network infrastructure, such as adding high transmission power RSUs near the edge of the V2X network and optimizing the multi-hop routing protocol, can help reduce V2X network delays. In the future, we suggest enhancing the proposed solution by utilizing parallel and graphics processing units (GPUs) commonly available in modern devices. This would significantly reduce the computational overhead, allowing V2X network operators to use high-strength cryptographic information, leading to a more secure network. Additionally, using system-on-a-chip (SoC) hardware solutions can help reduce computational overhead while increasing security. Our proposed security scheme can be applied to different V2X scenarios which need to be further studied. One such scenario is V2C: messages can be sent to cloud servers, where vehicles and RSU will collect information about road conditions, traffic patterns, weather information, driver and vehicle performance, and other data required by AI and ML algorithms. Usually, they are collected at vehicles and RSU and transferred to cloud servers for processing. These kinds of data can be encrypted using the full public key of an entity with ElGalmal encryption. Then, cloud servers can decrypt the data later. Another potential scenario is direct messages to vehicles. In AI and ML-based V2X, applications might need to send messages to vehicles, for example, change routes or request lane change. These kinds of data can be encrypted using the full public key of an entity with ElGalmal encryption. Then, the receiving vehicle can decrypt the message with its private key. A key challenge in implementing this protocol on a large scale is deploying V2X infrastructure in the real world, ensuring most vehicles are connected to the V2X network via 5G or Wi-Fi, and ensuring an adequate number of RSUs are installed in road infrastructure. While this challenge is outside the scope of this research, it is an essential consideration for the practical implementation of the proposed protocol. Furthermore, provided that the V2X infrastructure is in place, implementing and scaling the proposed protocol in cloud infrastructure are expected to be easy. The proposed protocol focuses on establishing a public/private key pair for each connected device, allowing any connected node to compute and validate the public key of any other connected device. This key pair can be used to secure decentralized or centralized awareness and warning messages, either for message encryption or adding a digital signature. However, integrating decentralized or centralized awareness and warning messages into the proposed protocol requires further evaluation in future research to determine its feasibility and effectiveness.