# A Lightweight Image Cryptosystem for Cloud-Assisted Internet of Things
## 3 Materials and Methods
### Proposed Lightweight Image Cryptography Algorithm
* Correlation Coefficient Analysis and Results Each of the figures in Figures 9-13 show the plain image, the graphs of the horizontal correlation coefficient (HCC), the vertical correlation coefficient (VCC), and the diagonal correlation coefficient of the adjacent pixels of the plain image in the first row, and the encrypted image, the graphs of the HCC, VCC, and DCC of the en \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline
**Image** & **PSNR** & **SC** & **SSIM** & **NCC** & **DCC** & **MSE** & **MAE** & **NAE** & **MD** & **AD** & **NPCR** & **UACI** \\ \hline airplane.tiff & 7.7561 & 0.9993 & 0.0075 & 0.0019 & 0.0019 & 10.901.08 & 85.2592 & 0.6679 & 255 & 42.6426 & 99.6025 & 33.435 \\ baboon.tiff & 7.7637 & 1.0024 & 0.0081 & 0.0028 & 0.0028 & 10.882.12 & 85.1354 & 0.667 & 255 & 42.6557 & 99.593 & 33.3864 \\ boat.tiff & 7.7586 & 0.9979 & 0.0078 & 0.0024 & 0.0024 & 10.894.76 & 85.1562 & 0.668 & 255 & 42.5446 & 99.5953 & 33.3946 \\ lena.tiff & 7.7697 & 0.9987 & 0.0094 & 0.0041 & 0.0041 & 10.867.12 & 84.9817 & 0.6671 & 255 & 42.4845 & 99.6162 & 33.3262 \\ pepper.tiff & 7.7388 & \(1\) & 0.0037 & \(-\)0.0016 & \(-\)0.0016 & 10,944.68 & 85.4524 & 0.6706 & 255 & 42.6269 & 99.6231 & 33.5107 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Plain image sensitivity analysis results. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline
**Image** & **PSNR** & **SC** & **SSIM** & **NCC** & **DCC** & **MSE** & **MAE** & **NAE** & **MD** & **AD** & **NPCR** & **UACI** \\ \hline airplane.tiff & inf & 1 & 1 & 1 & 1 & 0 & 0 & 0 & 0 & 0 & 0.0004 & 0 \\ baboon.tiff & inf & 1 & 1 & 1 & 1 & 1 & 0 & 0 & 0 & 0 & 0 & 0.0004 & 0 \\ boat.tiff & inf & 1 & 1 & 1 & 1 & 0 & 0 & 0 & 0 & 0 & 0.0008 & 0 \\ lena.tiff & inf & 1 & 1 & 1 & 1 & 0 & 0 & 0 & 0 & 0 & 0.0008 & 0 \\ pepper.tiff & inf & 1 & 1 & 1 & 1 & 0 & 0 & 0 & 0 & 0 & 0.0008 & 0 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Cipher image sensitivity analysis results. Figure 8: Histogram analysis of the plan and encrypted pepper.tiff. Figure 7: Histogram analysis of the plan and encrypted lena.tiff. Figure 9: Correlation analysis of the plain and encrypted airplane.tiff. Figure 11: Correlation analysis of the plain and encrypted boat.tiff. Figure 10: Correlation analysis of the plain and encrypted baboon.tiff. Figure 12: Correlation analysis of the plain and encrypted lena.tiff. Figure 13: Correlation analysis of the plain and encrypted pepper.tiff. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Image** & **Plain image** & **Encrypted image** \\ \hline airplane.tiff & 6.66391 & 7.99934 \\ baboon.tiff & 7.76244 & 7.99941 \\ boat.tiff & 7.19137 & 7.99932 \\ lena.tiff & 7.7502 & 7.99941 \\ pepper.tiff & 7.66983 & 7.99927 \\ \hline \hline \end{tabular} Analysis of Memory Utilization during the Encryption and Decryption Processes of the HXP

Tables 11 and 12 show the memory utilization by each line in the code when the encryption and decryption modules were implemented in python, respectively.

\end{table} 
Table 10: Entropies of the plain images in Figure 3f-j and the encrypted images in Figure 3k\(-\)o. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Plain image**} & \multicolumn{3}{c}{**Encrypted image**} \\ \hline
**Image** & **Chi-square** & \(p\)**-Value** & **Remark** & **Chi-square** & \(p\)**-Value** & **Remark** \\ \hline airplane.tiff & 564,672.6 & 0 & not uniform & 216.5977 & 0.961 & Uniform \\ baboon.tiff & 134,688.4 & 0 & not uniform & 225.127 & 0.911 & Uniform \\ boat.tiff & 381,445.8 & 0 & not uniform & 280.6582 & 0.129 & Uniform \\ lena.tiff & 91,011.39 & 0 & not uniform & 209.1113 & 0.984 & Uniform \\ pepper.tiff & 79,851.4 & 0 & not uniform & 289.3418 & 0.069 & Uniform \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Results of Chi-square analysis for Figures 4–8.