# The Security Perspectives of Vehicular Networks: A Taxonomical Analysis of Attacks and Solutions
## 4 Security Solutions
### Key-Based Solutions for VANETs  
This approach is more conventional than the ID-based cryptographic solutions. In this approach, public keys are used, which may be symmetric and asymmetric keys. These solutions are known as Public Key Infrastructure (PKI), but they also use private keys and hash functions as well. The main difference between these solutions and ID-based solutions is the use of certificates [102]. An Authenticated Routing protocol (ARAN) is shown in [103]. It uses certificates of authentication. Simplicity of the protocol make it significant to use in VANETs. Ariadne protocol is introduced in [104]. It uses initial route request timeout, maximum route request timeout, cache size, and cache replacement policy for the security purpose. 41.7% lower packet overhead has been achieved by this protocol. SEAD protocol is shown in [105]. Periodic route update interval, maximum packets buffered per node per destination, hash length (\(q\)), periodic updates: these parameters are used for the solution process. It claims to obtain a 95% packet delivery ration, which is very efficient. An explicit VANET oriented protocol is introduced in [44]. It enforces privacy in V2I communication; hence, it is named as Vehicle-to-Infrastructure communication Privacy Enforcement pRotocol (VIPER). It uses \(G\) (the group size), \(n\) (the message batch size), and \(pf\) (the probability of forwarding) for the security solution. VIPER is efficient in terms of low computations, reduced time delays, and less count of initialization messages. Another cryptography solution in this direction is noteworthy [43]. The solution named as Mobile Payment Protocol uses less communication and computation cost, and therefore, it is suitable for VANET applications. The summarization of this research is shown in Table 6.  
\begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**Reference(s)** & **Year** & **Service** & **Attack Type Handling** & **Research Gap** \\ \hline [PERSON] et al. [95] & 2006 & Authentication, Confidentiality, Non-repudiation, Integrity, Confidentiality, Non-repudiation, Integrity & Modification attack, Man-in-the-middle, Replay attack & Validation incomplete \\ \hline [PERSON] et al. [96] & 2010 & Authentication, Non-repudiation, Integrity, Confidentiality & Forgery, Man-in-the-middle, Replay attack & Validation incomplete \\ \hline [PERSON] and [PERSON] [97] & 2010 & Confidentiality, Authenticity & Impersonation attack, Modification attack & More efficiency required in revoking public key certificates \\ \hline [PERSON] et al. [98] & 2015 & Confidentiality, Privacy & Impersonation attack, Modification attack, Man-in-the-middle, Replay attack, token verifier table attack & Validation is not successful in VANETs. \\ \hline [PERSON] et al. [99] & 2019 & Authentication & Forgery attack & Suitable only for V2V communication \\ \hline [PERSON] et al. [100] & 2019 & Authentication, Privacy & Impersonation attack, Modification attack, Man-in-the-middle attack, Replay attack, Session key enclosure & Used only for V2 ehicle to RSU communication \\ \hline [PERSON] et al. [101] & 2020 & Privacy & Impersonation attack, Modification attack, Man-in-the-middle, Replay attack & Validation incomplete \\ \hline \hline \end{tabular}
\end{table}
Table 5: _Cont._