Page 13 - 2024-Vol20-Issue2

9| Yousif, Hameed & Al-Zuhairi

(a) (b)
Fig. 4. (a)The Ciphered Image (b) The Deciphered Image

(a) (b) (c)

Fig. 5. Images Histograms (a) Plain Image (b) Cipher Image (c) Decipher Image

5000 couples of neighboring pixels are randomly chosen in 4) Mean Square Error (MSE) and Peak Signal to Noise
the three directions: vertical, horizontal and diagonal from Ratio (PSNR) Analysis:
the same position of the original and its ciphered images for
computing the correlation coefficient values. The outcomes of For assessing the security and efficiency of TIC, two com-
correlation coefficients between neighboring pixels for the six mon metrics are utilized: MSE and PSNR. These metrics are
test images and their ciphered versions are displayed in Table described as [24, 25]:
III. It can be noticed from Table III that the values of correla-
tion coefficients at the three directions of the input image are = 1 NN (11)
almost one, whereas these values are approximately zero in ×N
the output ciphered images. The diagrams of pixel distribu- [X(i, j) -Y (i, j)]2
tion over horizontal, vertical and diagonal directions from the
input and its corresponding cipher images for Lena image are i=1 j=1
shown in Fig. 6. The results manifest that most pixel couples ? ?MSE
in the plain image are grouped about the main diagonal, while N
these couples are almost equally distributed over the entire
level in the ciphered image. It can be concluded from Table PSNR = 10 × log10 255 × 255 (12)
III and Fig. 6, that the TIC scheme can effectively remove MSE
the correlation among the adjoin pixels in the original image
and therefore it possesses a sturdy capability of tolerating the where X(i, j)and Y (i, j) represent the pixels values of the plain
statistical analysis. and ciphered/deciphered images, respectively. N represents
the image size. Higher MSE and lower PSNR values indicate
lesser similarity between the original and the ciphered images,
while lower MSE and higher PSNR values imply higher simi-
larity between the original and deciphered images. The values
of MSE and PSNR between the original and the encrypted
images are listed in Table II. The outcomes in this table sug-
gest that the values of MSE are extremely high and the PSNR