Permutation techniques based on discrete chaos and their utilization in image encryption

To achieve the Shannon's confusion and diffusion properties, an image encryption algorithm should include permutations and substitutions. This paper presents three different permutation techniques based on discrete chaotic maps. The permutation techniques are, then, evaluated using two measures: the average distance one pixel moved and the average distance between two adjacent pixels. The evaluation is performed for different matrix sizes and considers the scrambling efficiency and the execution time ratios. Furthermore, each of the permutation techniques is used in a simple encryption system and the encrypted images are evaluated using correlation coefficients, differential attack measures, the NIST statistical test suite and sensitivity analysis where promising encryption results are obtained.