## 5 Results and Discussion
Figure 10 summarizes the overall performance results to evaluate the efficiency of the proposed system. We can see that, in  
Figure 9: AV access rates per session key via the cloud: session key = 2 s; time periods: 10, 20, and 30 min. each scenario, edge-to-fog, fog-to-cloud, fog-to-fog, and cloud-to-cloud communication was initiated and successfully carried out by applying a session key of 2 s. However, the performance results as per each scenario are varied, but they are still under the limits of the session key. For communication scenarios such as edge-to-fog and fog-to-fog, all the associate responses from clouds are observed to evaluate the status of each cloud (either active or inactive). To the best of our knowledge, for each transaction (\(T\)), each cloud status was observed as an active status; therefore, from Figure 11, we can assume that each cloud response was always linear, or in order. Therefore, as per the study design and its overall measured results in each communication, we can conclude that this study is an extension of the existing available works [12; 16; 17; 33; 36], and of others that employ the emerging fog and blockchain technologies as add-ons to manage overall parking operations and security for the existing IoT-cloud-based SP systems [5; 7; 9; 34]. In reality, IoT-cloud systems come with the heterogeneity of resource constraint that necessitates having a friendly and secure architecture to enable an efficient SP system. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Scenario**} & \multicolumn{5}{c}{**FN**; CS} \\ \cline{2-6}  & \(\mathbf{H}\), 256 Bits & \(\mathbf{(FN)}_{\text{n+2}}\) (\(\mathbf{CS}_{\text{n+1}}\)) & \(\mathbf{(FN)}_{\text{n+2}}\) (\(\mathbf{CS}_{\text{n+1}}\) & \(\mathbf{(FN)}_{\text{n+1}}\) (\(\mathbf{CS}_{\text{n+1-1}}\)) \\ \hline \multirow{6}{*}{Fog-to-Fog} & bs43c2 fc386f12 ab0 fee54b8e34e8e1e5e58c58b8 dc8 bdd0e35c28d0597 aa & \(\approx 1\) & \(\approx 1\) & \(\approx 1\) \\ \cline{2-6}  & sd843c2 fc386f12 ab0 fee54b8e34e8e1e5e58c58b8 dc8 bdd0e35c28d0597 aa & \(\approx 1\) & \(\approx 1\) & \(\approx 1\) \\ \cline{2-6}  & sd71644 dc06b38d44f6 ad5b40b5 db435 ef7 bba5 da6 ea511c27e642a39017d & \(\approx 1\) & \(\approx 1\) & \(\approx 1\) \\ \cline{2-6}  & 096e52882 fd4 ba23b5364413d57c28 aa9 ee60c4a71766452b5 aeaf05 eld & \(\approx 1\) & \(\approx 1\) & \(\approx 1\) \\ \cline{2-6}  & dd63 fd9427389 sa6 da9a580d7a3f1534c1 ce76e90 ac751c1030e1b9d54d & \(\approx 1\) & \(\approx 1\) & \(\approx 1\) \\ \hline \multirow{6}{*}{Cloud-to-Cloud} & 14b562 da8e915 ac5 de2 bc45613e374 cb9f6 da6 eeee56 cdf484d080979c6 & \(\approx 1\) & \(\approx 1\) & \(\approx 1\) \\ \cline{2-6}  & 3 df505746963c16983 dc2442 db3c139e10385b40a0f08729169e3c7a25a30 & \(\approx 1\) & \(\approx 1\) & \(\approx 1\) \\ \cline{2-6}  & fab4905c26 aeccf538b1 cd1e547566980c2d4244721 ea6b0383 ab349 ab1780 & \(\approx 1\) & \(\approx 1\) & \(\approx 1\) \\ \cline{2-6}  & 5054a90 dbca80a72660a098 abd7d2b5b6 cea9d9398b0 dc44 dce29272879 ae511 & \(\approx 1\) & \(\approx 1\) & \(\approx 1\) \\ \cline{2-6}  & bbcd939 cc548 ac1 dd5581 ba142623477 dd6b22d46e6a8 cd58d4 df90c182d8 & \(\approx 1\) & \(\approx 1\) & \(\approx 1\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Proof of Transaction. Figure 10: Performance results per communication scenario: session key = 2 s; time periods: 10, 20, and 30 min.