Performance of the 2D Coupled Map Lattice Model and Its Application in Image Encryption
Algorithm 1
The proposed image encryption algorithm.
Input: The original image with size
Output: The cipher image
(1)
Use SVD to decompose and get the inverse-transformed image
(2)
Divide the inverse-transformed image into , and to get the new matrix
(3)
Divide into small blocks with size
(4)
whiledo
(5)
(6)
end
(7)
(8)
whiledo
(9)
(10)
end
(11)
Divide the sequence into three 2D matrices ,, with size to form the R, G, B channel of the cipher image ;(i)Step 1: For an original image with size , use SVD to decompose and keep of the singular values. Then, separate the inverse-transformed image into ,, and according to its color channels. Stack the three matrices ,, and to get a new matrix with size .(ii)Step 2: Divide matrix into small blocks with size , and in total there will be blocks. Use the following equation:with and to confuse the blocks of matrix for a few times . The resultant block-shuffled matrix is denoted as .(iii)Step 3: Stack row by row to get a sequence of length and generate a chaotic sequence of length with the method in Section 4, and then diffuse for some times by the following equation:where and .(iv)Step 4: Divide sequence into three 2D matrices ,, and with size to form the R, G, and B channel of the cipher image .
