Analytic Study of a Novel Color Image Encryption Method Based on the Chaos System and Color Codes

Algorithm 4

(Image decryption).

	Input. Encrypted image, secret keys , PWLCM (1), CLM (2).
Output. Plain color image
Step 1. The encrypted image matrix is placed in an array of size
Step 2. As in step 1 and step 2 in Algorithm 3, the receiver generates a sequence R of size L by secret key and CLM (2)
Step 3. Each element of in step 2 is passing through the following formula:
,
Step 4. By using key K2, receiver generates matrix Kp as in Algorithm 2, which is self-invertible matrix
Step 5.Convert one-dimensional array into submatrices of order
Step 6. Key mixing is reversed by using the formula
Step 7. Rewrite all ’s in the form of one-dimensional array
Step 8. By iterating the PWLCM and using the shared secret key , get a sequence and get by sorting in ascending order
Step 9. The permutation array is computed by inverse transform position
Step 10. Use on to get
Step 11. Reshape in a matrix form of order and converted to image