# Virtual Pseudonym-Changing and Dynamic Grouping Policy for Privacy Preservation in VANETs
## 2 Related Work
\begin{table}
\begin{tabular}{l l l l l l l l} \hline \hline
**Ref:** & **Execution Mode** & **Evaluation Metric** & **Procedure** & **Adversary Model** & **Accountability** & **Cost of** & **Impact on** \\  & & & & & & & & **Applications** \\ \hline
[13] & Infrastructure less & Anonymity & \
\begin{tabular}{l} Using dummy \\ data \\ \end{tabular} &
\begin{tabular}{l} External global \\ adversary \\ Global passive \\ adversary \\ \end{tabular} & No & Reduced & Yes \\
[17] & Infrastructure less & \begin{tabular}{l} ASS, entropy, \\ traceability \\ \end{tabular} & \
\begin{tabular}{l} Silent mode \\ \end{tabular} &
\begin{tabular}{l} Global passive \\ adversary \\ \end{tabular} & No & Not calculated & Reduced \\
[43] & Infrastructure less & Protection rate & \begin{tabular}{l} Cooperative \\ \end{tabular} & \
\begin{tabular}{l} General adversary \\ Identity \\ \end{tabular} &
\begin{tabular}{l} No \\ GPA \\ \end{tabular} & No & Not given & Yes \\
[21] & Infrastructure-based & \begin{tabular}{l} Sain \\ Anonymity, entropy, \\ tracking percentage \\ \end{tabular} & \
\begin{tabular}{l} Triggerged- \\ based \\ \end{tabular} &
\begin{tabular}{l} External passive \\ adversary \\ \end{tabular} & Yes & Not calculated & No \\
[33] & Infrastructure less & \begin{tabular}{l} Anonymity, \\ traceability \\ \end{tabular} & \
\begin{tabular}{l} Silent mode \\ \end{tabular} &
\begin{tabular}{l} Global passive \\ adversary \\ \end{tabular} & No & Not mentioned & No \\
[36] & Infrastructure-based & \begin{tabular}{l} ASS, entropy, \\ traceability \\ \end{tabular} & \
\begin{tabular}{l} Route \\ confusion \\ \end{tabular} &
\begin{tabular}{l} General attacker \\ \end{tabular} & No & Not mentioned & Yes \\
[44] & Infrastructure-based & \
\begin{tabular}{l} ASS, entropy, \\ selection \\ \end{tabular} &
\begin{tabular}{l} Passive adversary \\ \end{tabular} & No & Increased & Yes \\
[45] & Infrastructure less & \begin{tabular}{l} ASS, entropy, \\ tracking probability \\ \end{tabular} & \
\begin{tabular}{l} Silent mode \\ \end{tabular} &
\begin{tabular}{l} Global passive \\ adversary \\ \end{tabular} & No & Reduced & Yes \\
[18] & Infrastructure less & \begin{tabular}{l} ASS, entropy, \\ confusion, \\ traceability \\ \end{tabular} & \
\begin{tabular}{l} Scheme \\ permutation \\ \end{tabular} &
\begin{tabular}{l} Global passive \\ adversary \\ \end{tabular} & Yes & Not computed & No \\
[46] & Infrastructure-based & \begin{tabular}{l} ASS, entropy, \\ tracking probability \\ \end{tabular} & \
\begin{tabular}{l} Cheating \\ detection \\ \end{tabular} &
\begin{tabular}{l} Global passive \\ adversary \\ \end{tabular} & No & Not mentioned & Yes \\
[47] & Infrastructure less & \begin{tabular}{l} ASS, entropy, \\ tracking probability \\ \end{tabular} & \
\begin{tabular}{l} Use dummy \\ data \\ \end{tabular} &
\begin{tabular}{l} Global passive \\ adversary \\ \end{tabular} & No & Not computed & Yes \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparative analysis of existing location privacy schemes. with the new one. There are some areas on the road network in which vehicles are moving at high speed and with lower traffic density such as highways or main roads affecting location privacy. Therefore, we propose a new dynamic grouping and virtual pseudonym-changing scheme that can be applied in such a road network scenario.