Image Encryption using Double Layer Chaos with Dynamic Iteration and Rotation Pattern

Abstract

This research proposes an encryption method for images based on dual chaos systems and dual hash functions. SHA-256 and SHA-512 are hash functions chosen to process plain images and private keys. The purpose of using hash functions on plain and key images is to increase encryption resistance against differential attacks and perform local encryption in each image zone. The proposed method consists of two stages of encryption, the first involves dual hash functions and confusion with a chaotic system by performing encryption based on zoning and rotation of the image. The second stage is a diffuse process using a logistic map. The proposed method is proven to be strong against various attacks that have been tested with various measuring tools such as entropy, histogram analysis, chi-square, number of changing pixel rate (NPCR), unified averaged changed intensity (UACI), and the avalanche effect (AE). This method also proved to work better than the state-of-the-art method in this research, significantly based on entropy, UACI, and NPCR