**3. Image Encryption Algorithm**

In the proposed algorithm, the secret key consists of 16 parameters {*x*1(1), *x*1(2), *n*1, *u*1, *x*2(1), *x*2(2), *n*2, *u*2, *x*3(1), *x*3(2), *n*3, *u*3, *x*4(1), *x*4(2), *n*4, and *u*4}, where *xi*(1), *xi*(2) are the first two values of the chaotic sequence, *ui* is the control parameter of the chaotic map, and *ni* is related to the length of the generated chaotic sequence. As shown in Figure 6, the first step in the encryption algorithm obtaining

chaotic sequences is based on the key. Then, confusion and diffusion are performed simultaneously. The details of the algorithm are introduced below.

**Figure 6.** The image encryption architecture.
