Algorithm 2 The diffusion on a single eight-base DNA-level cube

Input: an eight-base DNA-level cube C after the permutation, an auxiliary hyperchaotic eight-base DNA-level cube G, the same prism length E of the cube C and G, and three hyperchaotic subsequences $H_j^d$ (j = 1, 2, 3)

Output: the eight-base DNA-level cube C after the diffusion

1: function CubeDiffusion($C,G,E,H_j^d$)

2:     $C(1,:,:)=\left(C\right(1,:,:)\oplus G(E,:,:\left)\right)\otimes \left(C\right(E,:,:)\oplus G(1,:,:\left)\right)$ with Rule $H_1^d\left(1\right)$;

3:     $C(:,1,:)=\left(C\right(:,1,:)\oplus G(:,E,:\left)\right)\otimes \left(C\right(:,E,:)\oplus G(:,1,:\left)\right)$ with Rule $H_2^d\left(1\right)$;

4:     $C(:,:,1)=\left(C\right(:,:,1)\oplus G(:,:,E\left)\right)\otimes \left(C\right(:,:,E)\oplus G(:,:,1\left)\right)$ with Rule $H_3^d\left(1\right)$;

5:     for i = 2 : E do

6:            $C(i,:,:)=\left(C\right(i,:,:)\oplus G(i-1,:,:\left)\right)\otimes \left(C\right(i-1,:,:)\oplus G(i,:,:\left)\right)$ with Rule $H_1^d\left(i\right)$;

7:            $C(:,i,:)=\left(C\right(:,i,:)\oplus G(:,i-1,:\left)\right)\otimes \left(C\right(:,i-1,:)\oplus G(:,i,:\left)\right)$ with Rule $H_2^d\left(i\right)$;

8:            $C(:,:,i)=\left(C\right(:,:,i)\oplus G(:,:,i-1\left)\right)\otimes \left(C\right(:,:,i-1)\oplus G(:,:,i\left)\right)$ with Rule $H_3^d\left(i\right)$;

9:     end for

10:   return C;

11: end function