A symmetric image encryption scheme based on a simple novel two-dimensional map

This paper proposes a new two-dimensional map. It can encrypt images by processing image stretch-and-fold. Firstly each pixel of the first column of a square image is inserted into adjacent two pixels of the first row one by one. Then each pixel of the last column is inserted into adjacent two pixels of the last row. Repeating the process for the rest of the image, it is stretched and joins a line of pixels. Secondly the line is fold over to a new square image with the same size to the plain-image. The map is divided into the left-map permutations and the right-map permutations. The numbers of the left-map permutations and the right-map permutations can be used as the secret key in encryption. The process shuffles the positions of image pixels. Compared with the prevalent two-dimensional map, Baker map, the new map has a simpler formulation, larger key space which is more adequate for image encryption. A new image encryption scheme based on the map is developed which is composed with a simple diffusion mechanism. The deciphering process is an invertible Process using the same keys. The simulation results validate the proposed image encryption scheme.