Image Scrambling Algorithms Based on Knight-tour Transform and its Applications

The scrambling algorithm based on knight-tour transform is a hot topic because the number of its secret key is large and its security is high. But the classical knight-tour based on the movement of (1,2) can only scramble the details of digital image. This paper discusses the improved scrambling algorithms based on knight-tour transform to overcome the shortage. They include (1) Improved scrambling algorithms based on producing matrix. (2) A block multilayer scrambling algorithm (3) A composite scrambling algorithm which is made of knight-tour transform and Arnold transform. The results of experiment indicate that the image which are scrambled by these three methods can not only hide the large contour and edge but also enlarge the number of the secret keys.