A New Chaotic Image Encryption Algorithm Based on L-Shaped Method of Dynamic Block

This paper proposes a new L-shaped method based on dynamic block, and combines it with one-dimensional chaotic system (Logistic map) and two-dimensional chaotic system (2D Logistic-adjusted-Sine map, 2D-LASM system) to generate chaotic sequence for image scrambling and diffusion. Firstly, the index of chaotic sequence is used to change the original position of image pixels value. Secondly, the image is dynamically divided into blocks according to the key, and scrambled within and between blocks. Each block is scrambled with L-shaped and Fisher-Yates method. Thirdly, in the diffusion stage, the pixel values are initially diffused at the bit-level based on the L-shaped method. Finally, four XOR diffusion formulas are designed, which are highly related to plaintext, and can be selected dynamically according to chaotic sequences. The image encryption algorithm is tested on grayscale image and color image respectively. The experimental results and security analysis show that the algorithm has good encryption effect, high security and can resist various attacks.

Automated summary

This paper proposes a new L-shaped method based on dynamic block, combined with one-dimensional and two-dimensional chaotic systems, for image scrambling and diffusion. Experimental results show that the algorithm has good encryption effect, high security, and can resist various attacks.