Hierarchical scrambling scheme for palette-based images

We present an efficient hierarchical scrambling scheme for palette-based images. The goal of hierarchical scrambling of a bit stream is to make the entire stream somehow difficult to decrypt. We decompose the original palette-based image into its corresponding binary bits then introduce cyclic shifts to scramble the selected entries and change their colors. The significant parameters (i.e. target pixels and target color components) play an important role in evaluating performance analysis. The scrambling scheme for the target pixels and the target color components were measured through a series of tests to measure the effectiveness of the proposed scheme. We also introduce an efficient key assignment scheme in which a recursive hash chain (RHC) is used to make our scheme secure.