# Blockchain-Based Authentication in Internet of Vehicles: A Survey
## 1 Introduction
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \multirow{2}{*}{**Ref.**} & \multirow{2}{*}{**Year**} & \multirow{2}{*}{**Target Area**} & **VANETs** & **Security** & **Blockchain-** & \multirow{2}{*}{**Features**} \\  & & & **to IoV** & **Attacks and/or** & **Based** & & \\  & & & **Transition** & **Requirements** & **Authentication** & & \\ \hline \multirow{9}{*}{[47]} & \multirow{9}{*}{2017} & \multirow{9}{*}{IoT} & \multirow{9}{*}{X} & \multirow{9}{*}{\(\surd\)} & \multirow{9}{*}{X} & \(\bullet\) & Discusses symmetric and \\  & & & & & & & asymmetric cryptographic-based \\  & & & & & & authentication protocols. \\ \cline{1-1}  & & & & & & \(\bullet\) & Covers authentication protocols \\ \cline{1-1}  & & & & & & in a wide range of IoT \\ \cline{1-1}  & & & & & & environments, namely, IoV, IoS, \\ \cline{1-1}  & & & & & & & IoE, and M2M. \\ \cline{1-1}  & & & & & & \(\bullet\) & Presents threat models, \\ \cline{1-1}  & & & & & & & securely verification techniques \\ \cline{1-1}  & & & & & & & \(\bullet\) & Surveys a range of \\ \cline{1-1}  & & & & & & & authentication schemes that are \\ \cline{1-1}  & & & & & & & based on cryptography, digital \\ \cline{1-1}  & & & & & & \(\bullet\) & Provides a performance \\ \cline{1-1}  & & & & & & \(\bullet\) & Comparison in terms of \\ \cline{1-1}  & & & & & & communication and \\ \cline{1-1}  & & & & & & computation overheads. \\ \hline \end{tabular}
\end{table} 
Table 1: Comparison of recent surveys on authentication in IoV and VANETs networks. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Ref. **} & \multirow{2}{*}{**Year**} & \multirow{2}{*}{**Target Area**} & \multicolumn{2}{c}{**VANETs**} & \multicolumn{2}{c}{**Security**} & \multicolumn{2}{c}{**Blockchain-**} & \multirow{2}{*}{**Features**} \\  & & & **to IoV** & **Attacks and/or** & & **Based** & & \\  & & & **Transition** & **Requirements** & **Authentication** & & & \\ \hline \hline \multirow{10}{*}{[49]} & \multirow{10}{*}{2019} & \multirow{10}{*}{IoT} & \multirow{10}{*}{X} & \multirow{10}{*}{\(\surd\)} & \multirow{10}{*}{X} & \multirow{10}{*}{\(\bullet\)} & Provides a multi-criteria & \\  &  
In order to highlight the contribution of this paper, a number of recent state-of-art surveys are summarized and compared in Table 1. In [47], the cryptographic-based authentication protocols have been discussed in a wide range of IoT environments, namely, IoV, Internet of Sensors (IoS), Internet of Energy (IoE), and Machine to Machine Communication (M2M). In [48], a range of authentication schemes that are based on cryptography, digital signature, and message verification in the context of VANETs have been presented. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Ref. **} & \multirow{2}{*}{**Year**} & \multirow{2}{*}{**Target Area**} & \multicolumn{2}{c}{**VANETs**} & \multicolumn{2}{c}{**Security**} & \multicolumn{2}{c}{**Blockchain-**} & \multirow{2}{*}{**Features**} \\  & & & & **to IoV** & **Attacks and/or** & **Based** & & \\  & & & & **Transition** & **Requirements** & **Authentication** & & & \\ \hline \multirow{9}{*}{[54]} & \multirow{9}{*}{2021} & \multirow{9}{*}{IoV} & \multirow{9}{*}{X} & \multirow{9}{*}{X} & \multirow{9}{*}{X} & \multirow{9}{*}{X} & \multirow{9}{*}{Provides seven different aspects for combining the blockchain technology with IoV while briefly surveying some schemes for each of these aspects.} \\  & & & & & & & & & \\  & & & & & & & & & \\  & & & & & & & & & \\  & & & & & & & & & \\  & & & & & & & & & \\  & & & & & & & & & & \\  & & & & & &  
IoV authentication has been implicitly reviewed in [49] by introducing a multi-criteria classification for the authentication schemes in the IoT environment in general. A broad range of crypto-based authentication schemes in VANETs environments [50; 51] and IoV networks [52] have also been reviewed.