# An Innovative Information Hiding Scheme Based on Block-Wise Pixel Reordering
## 3 Proposed Scheme
### Data Hiding
An information entropy value closer to 8 means that the encrypted image has higher randomness. In Section 4.1, we evaluate the performance of our proposed scheme under different test images. We give some execution results and security analysis in Section 4.2. Section 4.3 gives comparisons with other SOTA schemes. ### Performances of Our Proposed Scheme

The embedding capacity of the proposed scheme is contingent upon the pixel-block size and the codeword table size. Therefore, we initially conducted performance tests on different test images by varying the pixel-block sizes in a codeword table. The group size in Tables 1 and 2 is what we call the codebook table size. \begin{table}
\begin{tabular}{l c c c c c} \hline \hline
**Image Name** & **Block Size** & **Group Size** & **EC** & **PSNR** & **SSIM** \\ \hline \multirow{8}{*}{Airplane} & \(1\times 8\) & 256 & 197,888 & 51.1497 & 0.9956 \\  & \(2\times 4\) & 256 & 197,888 & 51.1327 & 0.9956 \\  & \(4\times 2\) & 256 & 197,888 & 51.1491 & 0.9956 \\  & \(2\times 8\) & 256 & 98,944 & 54.1349 & 0.9978 \\  & \(3\times 8\) & 256 & 64,932 & 55.9329 & 0.9985 \\ \hline \multirow{8}{*}{Baboon} & \(1\times 8\) & 256 & 197,888 & 51.1499 & 0.9987 \\  & \(2\times 4\) & 256 & 197,888 & 51.1469 & 0.9987 \\  & \(4\times 2\) & 256 & 197,888 & 51.1329 & 0.9987 \\  & \(2\times 8\) & 256 & 98,944 & 54.1787 & 0.9994 \\  & \(3\times 8\) & 256 & 64,932 & 55.9347 & 0.9996 \\ \hline \multirow{8}{*}{Barbara} & \(1\times 8\) & 256 & 197,888 & 51.1360 & 0.9972 \\  & \(2\times 4\) & 256 & 197,888 & 51.1542 & 0.9972 \\  & \(4\times 2\) & 256 & 197,888 & 51.1450 & 0.9972 \\  & \(2\times 8\) & 256 & 68,944 & 54.1392 & 0.9986 \\  & \(3\times 8\) & 256 & 64,932 & 55.9208 & 0.9991 \\ \hline \multirow{8}{*}{Boat} & \(1\times 8\) & 256 & 197,888 & 51.1419 & 0.9972 \\  & \(2\times 4\) & 256 & 197,888 & 51.1469 & 0.9972 \\  & \(4\times 2\) & 256 & 197,888 & 51.1410 & 0.9972 \\  & \(2\times 8\) & 256 & 98,944 & 54.1624 & 0.9986 \\  & \(3\times 8\) & 256 & 64,932 & 55.9081 & 0.9991 \\ \hline \multirow{8}{*}{Couple} & \(1\times 8\) & 256 & 197,888 & 51.1399 & 0.9975 \\  & \(2\times 4\) & 256 & 197,888 & 51.1316 & 0.9975 \\ \cline{1-1}  & \(2\times 8\) & 256 & 197,888 & 51.1489 & 0.9975 \\ \cline{1-1}  & \(3\times 8\) & 256 & 98,944 & 54.1454 & 0.9987 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Performance of different block sizes with the same group size of 256. Table 1 lists the results of applying the proposed scheme to the test images for different pixel-block size configurations with the same codebook table size. We observed that when pixel-blocks have an identical number of pixels, the shapes of the pixel-blocks had no effect at all on EC values depicted in Table 1; the shapes also had no significant impact on PSNR and SSIM. Therefore, we could simplify our scheme by converting the encrypted images to a pixel stream first and specifying the size of a pixel-block without the necessity of specifying the width and the height of a pixel-block. However, the number of pixels within a pixel-block had a significant effect on EC, and the larger the size of the pixel-block, the less EC the proposed scheme could provide. Moreover, the larger the pixel-block, the higher the PSNR and SSIM values of the recovered image when the size of the codebook