# Evolution of V2X Communication and Integration of Blockchain for Security Enhancements
## 1 Introduction
The decentralized MEC system in vehicular networks offers various advantages, including ubiquitous network connections, increased scalability, and decreased complexity in network operations, and it helps in the development of 5G V2X services. The data computing is vulnerable to malicious attacks in the dynamic edge-computing environment such as jamming attacks, sniffing attacks, denial-of-service attacks (DoS), etc. Furthermore, the edge servers must be reliable and secure, but they can be compromised because of the high dynamicity and accessibility of the MEC-based V2X networks. A further challenge is to protect data privacy and immutability from external modifications or alternations. The rapid and explosive growth in 5G V2X traffic data generated by high-density vehicles has led to strong demands for network defense systems against various cyber-attacks. Blockchain is expected to offer a range of security services for 5G V2X and edge computing with powerful security properties to enhance overall performance of future V2X networks. Blockchain comes as a suitable candidate to resolve such challenges by securing transactions and verifying the user connections. Blockchain systems provide strong data security by storing data in a distributed ledger, where data are signed and appended immutably to blocks. Blockchain can deliver a wide variety of security advantages, such as access control provided by smart contracts, data integrity, and an efficient consensus verification mechanism. Because of the time-varying channels in V2X, unpredictable network traffic, high-performance protocols and stringent requirements for numerous emerging technologies (edge computing, blockchain and 5G networks) cannot achieve their goal independently. Therefore,all of the above technologies should be combined, and linked with each other in order to fulfill the essential requirements and functional criteria of the next-generation of vehicular networks. The 5G-based edge cloud computing provides appropriate services in V2X by collecting, storing, and managing large amount of heterogeneous data. However, new technologies also introduce additional security and privacy issues in integrated 5G and edge based V2X. The outsourcing of huge data to the MEC servers raises serious issues that are linked with the data privacy. Some of the major issues and challenges include data availability, data integrity, data privacy management, confidentiality, heterogeneity, effective wireless resource management, resource scaling, transparency, and immutability. The introduction of blockchain in integrated 5G-based edge computing in vehicular networks provides some advantages, yet, there are issues that are related to scalability and performance based on storage, throughput, incentive, and network resources. Some of the examples of security flaws in integrated blockchain in 5G-based MEC are time-stamping dependency, mismanaged exceptions, re-entry attacks on smart contracts, and privacy leakage due to the involvement of malicious nodes in the network. All of these issues need to be addressed carefully before implementing 5G networks and edge computing in realistic situations in vehicular networks. There is research being carried out using blockchain in V2X communication along with 5G-based edge computing networks [3]. By integrating blockchain in 5G-based edge computing in V2X networks, Road Side Units (RSUs), or 5G Radio Access Networks (RANs) can be equipped with MEC storage servers to incorporate MEC and 5G. A fast and effective consensus mechanism is required for efficient block verification to sustain the permissioned blockchain. The integration of the above technologies include a range of services, including convergence, localization, traffic information gathering, traffic data management, communication, and access to the internet services with edge-cloud service layer support. However, there are some gaps that need to be filled for full convergence.