Cryptanalysis and Improvement on an Image Encryption Algorithm Design Using a Novel Chaos Based S-Box

Abstract

This article performs the cryptanalysis of an image encryption algorithm using an S-box generated by chaos. The algorithm has the advantages of simple structure, high encryption efficiency, and good encryption performance. However, an attentive investigation reveals that it has some undiscovered security flaws. The image cryptosystem is totally breakable under proposed chosen-plaintext attack, and only two chosen plain-images are required. An array equivalent to the S-box is constructed by an elaborately designed chosen-plaintext image, and the cipher-image is deciphered without having to know the S-box itself. Both mathematical deduction and experimental results validate the feasibility of the attacking scheme. Furthermore, an improved encryption scheme is proposed, in which a feedback mechanism is introduced, a bidirectional diffusion scheme is designed, and values of the ciphertext are associated with more parameters in each diffusion process. Testing results and security analysis verify that the improved cryptographic system can achieve a higher security level and has a better performance than some of the latest encryption algorithms.

A Multidimensional Hyperjerk Oscillator: Dynamics Analysis, Analogue and Embedded Systems Implementation, and Its Application as a Cryptosystem

“…An image histogram is the representation of each pixel in the image with respect to its intensity value [55][56][57]. This analysis is very useful in deciding the statistical strength of an encryption algorithm.…”

“…An efficient and robust encryption algorithm must show sensitivity to even the slightest changes in the composition of its secret key [38][39][40][41][55][56][57]. This is especially important in resisting brute force attacks.…”

“…Step 8: (h*w) steps are required for number of exclusive-XOR operations in the final step Therefore, the complexity of the algorithm proposed to execute the encryption procedure is O(max(h 2 , w 2 , h*w) which is an improvement over the complexity reported in [55].…”

When an attacker meets a cipher-image in 2018: A year in review

“…permutation vector W = {w(i)} is a bijective map on D, the supporting domain of the plain-image, i ∈ D; value ⊞ denotes an arithmetic operation, g is a fixed nonlinear function, and H = {h(i)} is a pseudo-random number sequence (PRNS). Only small number of chaotic image encryption schemes use S-box [6,7,8]. There are some papers focusing on designing S-box with chaotic maps [9,10,11,12].…”

“…There are some papers focusing on designing S-box with chaotic maps [9,10,11,12]. In [6,13,14,15,16,17,18,19,20], the analyzed image encryption schemes are fixed to withstand the proposed attacking methods. Due to the seemingly similar properties of a chaotic system and a secure pseudo-random number generator (PRNG), a large number of image encryption schemes use various chaotic maps to generate PRNS, which is used to control combination of some basic encryption operations, e.g.…”