Chaos-Based Synchronized Dynamic Keys and Their Application to Image Encryption with an Improved AES Algorithm

Chih-Hsueh Lin,Jun-Juh Yan,Guo-Hsin Hu,Che-Yu Chan

doi:10.3390/app11031329

Abstract

This study aimed to design chaos-based synchronized dynamic keys and develop an improved chaos-based advanced encryption standard (AES) algorithm with the proposed synchronized random keys. First, based on sliding mode control (SMC) technology, a rippling control scheme was introduced to guarantee the synchronization between master–slave discrete chaotic systems. Under the synchronization, the same dynamic random chaos signals could be simultaneously obtained at the transmitter and receiver in communication systems. Then, a novel modified AES cryptosystem with dynamic random keys based on chaos synchronization was presented. In a traditional AES cryptosystem, a static key is used, and it must be exchanged in advance and confirmed to be safely kept. However, in the proposed design, by introducing the synchronization technology of chaotic systems, the static key becomes dynamic and random, and it does not need to be kept or transmitted in open channels. Consequently, the disadvantage of key storage could be eliminated and the security of encryption could be improved. Finally, the developed chaos-based AES (CAES) algorithm has been applied to construct a novel image encryption algorithm. The statistical analysis, histogram, information entropy, and correlation indexes have been calculated and analyzed through simulation experiments in order to demonstrate the capability and improvement of this presented CAES cryptosystem.

Highlights

Since the high-speed growth and wide application in the field of the multimedia information and internet technology, the security demands for data communication and image information confidentiality have continually increased [1]
A hybrid approach combined with a fast chaotic algorithm and advanced encryption standard (AES) image encryption was proposed in the literature [6]
The initial conditions play the role of secure keys, and their encryption algorithms are quite secure if the assumption is valid

Summary

Introduction

Since the high-speed growth and wide application in the field of the multimedia information and internet technology, the security demands for data communication and image information confidentiality have continually increased [1]. Only some mixed information, that is not related to system parameters and initial values, needs to be transmitted to the receiving end, and a synchronization controller can be constructed so that the transmitting and receiving ends can simultaneously generate the same chaotic random sequence. In this way, it could be applied to design a new encryption system with high security. In [10], a simple synchronization controller subjected to uncertain chaotic parameters was proposed, and extended the chaos synchronization to construct secure communication systems This method was is applicable for encrypting a large amount of data. Among these proposed approaches for control design, the sliding mode control method is frequently used because it has an inherently good robustness, especially for matched disturbances

Objectives

Methods

Conclusion