Design of image cipher using block-based scrambling and image filtering

The operation of image filtering is widely used to deblur digital images. However, using inappropriate masks, it can also blur images. Motivated by this concept, this paper introduces an image cipher using block-based scrambling and image filtering (IC-BSIF). To the best of our knowledge, this is the first time that image filtering has been used for image encryption. IC-BSIF uses the well-known substitution-permutation network and strictly follows the concepts of confusion and diffusion. The block-based scrambling is able to separate neighboring pixels to different rows and columns, and thus can efficiently weaken the strong correlations between adjacent pixels. Using randomly generated masks by the secret key, the image filtering can spread little change of plain-images to the entire pixels of cipher-images. Simulation results show that IC-BSIF can encrypt different kinds of images into noise-like ones, and security evaluations demonstrate that it can achieve better performance than several state-of-the-art encryption schemes.