# Blockchain Application in Internet of Vehicles: Challenges, Contributions and Current Limitations
## 6 Conclusions  
This article explored challenges and opportunities in the blockchain-enabled IoV domain, extracted from papers between 2017 and 2021. The authors acquired a number of articles by utilizing a rigorous search filtration method; however, some were deemed to be irrelevant. Initially, the authors investigated the current challenges in the area of IoV-assisted smart grids, concluding that the major concerns are related to high mobility, the complexity of the interconnected EVs and other IoV objects (e.g., RSUs), and demand response. Then, the authors explored the blockchain applications in IoV-assisted smart grids in various fields including, among others, P2P energy trading among EVs, IoV management, data protection and blockchain performance. In addition to reviewing diverse blockchain contributions in the IoV, the authors suggested several potential avenues for beginner researchers to pursue. Those directions mainly include blockchain performance and scalability, resource constraints, privacy and security issues, IoV-specific consensus algorithms, incentive mechanisms, legal and regulatory aspects, as well as efficient demand response management. The current review revealed that blockchain provides disinterme \begin{table}
\begin{tabular}{c c} \hline \hline
**Observation** & **Description** \\ \hline OB.1 & IoV needs decentralization in terms of energy management \\ OB.2 & Real-time monitoring of the connected objects in the IoV is critical \\ OB.3 & Energy generation and consumption in the IoV may affect the demand and \\  & response in smart grids \\ OB.4 & EV energy trading and charging procedures must effectively represent \\ OB.5 & Private information of the EVs are exposed resulting in privacy and \\ OB.6 & EVs with surplus energy are not motivated to participate as energy sellers \\ OB.7 &
\begin{tabular}{c} due to the lack of incentive mechanisms \\ \end{tabular} \\ OB.8 & Blockchain can be used for fair payments during energy trading without \\ OB.8 & Blockchain can provide security and privacy through EV identity \\  & management and data encryption \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Observations derived from the systematic literature review findings. diation, confidentiality and tamper-proof transfers, and it also provides innovative ways for EV drivers to participate more actively in the IoV concept and to benefit from their properties. Based on the findings of the conducted systematic literature review, the authors highlighted a set of observations as the basis for further research. Based on the authors' observations, the main limitation that needs to be addressed is the centralized management of the IoV, and the need for real-time monitoring of all the connected objects (i.e., vehicles, charging stations, road-side units, parking lots, etc.) in the network. Moreover, it was observed that energy generation and consumption in the IoV may affect the demand and response in smart grids. Therefore, EVs' energy trading and charging procedures should effectively represent demand-supply balance in the grid, and consequently in all parts of a smart city. As derived from the current review, there are several research studies that provide solutions to manage demand by trading energy in a V2V and/or V2G manner. However, it was noticed that objects in the IoV (i.e., especially EV and charging stations) face various limitations, such as security and privacy issues and a lack of incentives. Finally, it was confirmed by all the studies included in this review that blockchain technology has a great potential in the area of IoV. Specifically, the findings of the current review stated that blockchain can be used, among other applications, for fair payments during energy trading without relying on untrusted third-parties, as well as to provide security and privacy through EV identity management and data encryption.