## 4 Performance
### Quantitative Analysis  
Table 1 shows the performance evaluation of the proposed technique in terms of the PSNR between the actual and decrypted images. The PSNR between the actual and  
Figure 8: (**a**) Palm X-ray; (**b**) brain tumor; (**c**) ultrasound; (**d**) chest X-ray.  
Figure 7: Visual analysis: (**a**) Sanchi spread image, \(512\times 512\), (**b**) watermarked image, \(256\times 256\), (**c**) chaotic calculated planned watermarked image, (**d**) Sanchi watermarked image, (**e**) RSA-encrypted image.  
decrypted images should be a maximum. It is clearly found that the proposed 185 technique achieves remarkably better PSNR values as compared to the existing techniques. The proposed techniques show an average improvement in terms of PSNR of 3.4587%.  
Table 2 demonstrates the performance evaluation of the proposed technique in terms of PSNR between the actual and encrypted images. The PSNR between actual and decrypted images should be a minimum. It is clearly found that the proposed technique achieves remarkably lower PSNR values as compared to the existing techniques. The proposed techniques show an average reduction in terms of PSNR of 1.6478%.  
Table 3 shows the performance evaluation of the proposed technique in terms of the entropy of the encrypted images. It should be at its maximum. It is clearly found that the proposed technique achieves remarkably better entropy values as compared to the existing techniques. The proposed techniques show an average improvement in terms of entropy of 0.8978%.  
Table 4 shows that there is no correlation among the adjacent pixels of the encrypted medical grayscale images. It can be seen that the pixels are loosely correlated to each other. Hence, no attacker can extract the statistical information to recover the encrypted images.  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Technique** & **Palm X-ray** & **Brain Tumor** & **Ultrasound** & **Chest X-ray** \\ \hline CGAN [13] & 56.62 & 47.31 & 40.16 & 51.86 \\ VMKS [15] & 56.52 & 43.77 & 47.51 & 52.99 \\ PEC [4] & 44.37 & 50.18 & 59.02 & 57.04 \\ JIL [16] & 58.21 & 52.55 & 51.12 & 59.32 \\ SET [17] & 57.12 & 56.94 & 43.53 & 57.02 \\ SHE [18] & 56.76 & 48.92 & 45.59 & 59.22 \\ Proposed & 59.41 & 58.14 & 60.22 & 60.52 \\ \hline \end{tabular}
\end{table}
Table 1: Performance evaluation of color images in terms of PSNR between actual and decrypted images.  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Technique** & **Palm X-ray** & **Brain Tumor** & **Ultrasound** & **Chest X-ray** \\ \hline CGAN [13] & 6.18 & 4.25 & 2.44 & 3.73 \\ VMKS [15] & 4.32 & 5.12 & 2.17 & 2.42 \\ PEC [4] & 4.57 & 4.55 & 6.58 & 3.61 \\ JIL [16] & 1.64 & 3.45 & 5.99 & 8.55 \\ SET [17] & 5.05 & 6.92 & 4.61 & 4.32 \\ SHE [18] & 3.29 & 4.94 & 5.31 & 2.08 \\ Proposed & 1.44 & 2.25 & 1.97 & 1.88 \\ \hline \end{tabular}
\end{table}
Table 2: Performance evaluation of color images in terms of PSNR between actual and encrypted images.  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Technique** & **Palm X-ray** & **Brain Tumor** & **Ultrasound** & **Chest X-ray** \\ \hline CGAN [13] & 7.76 & 7.26 & 7.54 & 7.6 \\ VMKS [15] & 7.51 & 7.59 & 7.45 & 7.39 \\ PEC [4] & 7.21 & 7.72 & 7.5 & 7.07 \\ JIL [16] & 7.65 & 7.37 & 7.03 & 7.43 \\ SET [17] & 7.6 & 7.7 & 7.52 & 7.53 \\ SHE [18] & 7.16 & 7.53 & 7.55 & 7.14 \\ Proposed & 7.59 & 7.53 & 7.38 & 7.43 \\ \hline \end{tabular}
\end{table}
Table 3: Performance evaluation of color images in terms of entropy.