An Image Encryption Scheme Based on Chaotic Map

Recently, the chaos based cryptographic algorithms have suggested some meaningful techniques to develop efficient image encryption schemes. In this paper, we propose a new digital image encryption scheme based on the piecewise linear chaotic map (PWLCM) in order to meet the requirements of the secure encryption. The proposed scheme is described in detail, along with the security analyses including key space analysis, sensitivity analysis, information entropy analysis and differential attack analysis. The results show that the suggested image encryption scheme has some properties desirable in a good security cryptosystem.

The current information age demands enormous opportunities, where, the sensitive data and information is being exchanged, analyzed and made use of. It has led to several concerns and challenges, mainly in the areas of information privacy, authentication and integrity. This concern, attracted cryptographers to device more effective methodologies and algorithms to ensure better protection to sensitive information. In this context, the application of chaotic based systems is considered to design a pseudorandom sequence generator, which is used as a key stream generator in the additive Stream Cipher system. Chaotic map is a mathematic function that generates highly nonlinear and random real sequence which is very sensitive to initial conditions. In this view, this work focusses on the study of Logistic map, considered from a bunch of various Chaotic functions available [1], [2]. Chaotic real sequence is binarized using a new binarization algorithm using Linear Feedback Shift Register (LFSR), which is designed in such a way that the randomness of Chaotic real sequence is not affected as far as possible. Using Logistic map, about 50 sequences are generated each of length ≥ 106. To ensure the randomness of binary sequences, NIST(National Institute of Standards and Technology) test is used. It is observed that, all the sequences have strictly passed most of the NIST tests with an average passing proportion ≥ 0.87. These sequences are used as key sequences in image encryption and decryption. It is interesting to observe that, encrypted image does not contain any residual information. This result is cross verified by plotting the Histogram, computing the Correlation coefficient and Entropy of the output images. It is observed that, Histograms are almost flat indicating the equiprobable distribution of pixels. Also, Entropy of the encrypted image is close to 8 and Correlation coefficient value is very negligible indicating that neighboring pixels are heavily uncorrelated. As the key sequence based on Chaotic functions is sensitive to initial conditions, the sequence generated will be highly nonlinear and random which encourages one to use in cryptographic applications.

An image encryption scheme based on new spatiotemporal chaos

Chaos and compressive sensing based novel image encryption scheme

Image encryption scheme based on 3D baker with dynamical compound chaotic sequence cipher generator

In this paper, we present a novel approach to create the new chaotic map and propose an improved image encryption scheme based on it. Compared with traditional classic one-dimensional chaotic maps like Logistic Map and Tent Map, this newly created chaotic map demonstrates many better chaotic properties for encryption, implied by a much larger maximal Lyapunov exponent. Furthermore, the new chaotic map and Arnold's Cat Map based image encryption method is designed and proved to be of solid robustness. The simulation results and security analysis indicate that such method not only can meet the requirement of imagine encryption, but also can result in a preferable effectiveness and security, which is usable for general applications.

A robust and secure chaotic standard map based pseudorandom permutation-substitution scheme for image encryption

This paper proposes a novel image block encryption algorithm based on three-dimensional Chen chaotic dynamical system. The algorithm works on 32-bit image blocks with a 192-bit secret key. The idea is that the key is employed to drive the Chen’s system to generate a chaotic sequence that is inputted to a specially designed function G, in which we use new 8x8 S-boxes generated by chaotic maps (Tang, 2005). In order to improve the robustness against differental cryptanalysis and produce desirable avalanche effect, the function G is iteratively performed several times and its last outputs serve as the keystreams to encrypt the original image block. The design of the encryption algorithm is described along with security analyses. The results from key space analysis, differential attack analysis, and information entropy analysis, correlation analysis of two adjacent pixels prove that the proposed algorithm can resist cryptanalytic, statistical and brute force attacks, and achieve a higher level of security. The algorithm can be employed to realize the security cryptosystems over the Internet.

An adaptive color image encryption scheme using chaotic generalized Arnold map is proposed. The three base color components of the plain-image with 256 grayscale levels are decomposed into 6 parts: 3 higher bit-planes parts and 3 lower bit-planes parts. The intensity values of all these 6 parts are summed to get one secrete key used to scramble the resulted 6 matrices by sort-based approach in a cross way. Chaotic sequences produced by one generalized Arnold map are applied to diffuse the scrambled three base color components crossly as well to get more encryption effects. An adaptive strategy is adopted in both the scrambling process and diffusion process, implying that the key streams are all related to the content of the plain-image. Therefore the image encryption scheme shows strong robustness against known/chosen plaintext attacks. Other performances are carried out, such as key sensitivity, histogram, correlation coefficients, information entropy and difference attack analysis. All the experimental results show that the proposed scheme is secure and effective for practical application.

Dynamic 3D scrambled image based RGB image encryption scheme using hyperchaotic system and DNA encoding

High security has always been the ultimate goal of image encryption, and the closer the ciphertext image is to the true random number, the higher the security. Aiming at popular chaotic image encryption methods, particle swarm optimization (PSO) is studied to select the parameters and initial values of chaotic systems so that the chaotic sequence has higher entropy. Different from the other PSO-based image encryption methods, the proposed method takes the parameters and initial values of the chaotic system as particles instead of encrypted images, which makes it have lower complexity and therefore easier to be applied in real-time scenarios. To validate the optimization framework, this paper designs a new image encryption scheme. The algorithm mainly includes key selection, chaotic sequence preprocessing, block scrambling, expansion, confusion, and diffusion. The key is selected by PSO and brought into the chaotic map, and the generated chaotic sequence is preprocessed. Based on block theory, a new intrablock and interblock scrambling method is designed, which is combined with image expansion to encrypt the image. Subsequently, the confusion and diffusion framework is used as the last step of the encryption process, including row confusion diffusion and column confusion diffusion, which makes security go a step further. Several experimental tests manifest that the scenario has good encryption performance and higher security compared with some popular image encryption methods.

A new image encryption scheme is proposed based on a delayed fractional-order chaotic logistic system. In the process of generating a key stream, the time-varying delay and fractional derivative are embedded in the proposed scheme to improve the security. Such a scheme is described in detail with security analyses including correlation analysis, information entropy analysis, run statistic analysis, mean-variance gray value analysis, and key sensitivity analysis. Experimental results show that the newly proposed image encryption scheme possesses high security.

Image encryption has been an attractive research field in recent years. The chaos-based cryptographic algorithms have suggested some new and efficient ways to develop secure image encryption techniques. This paper proposes a novel image encryption scheme, which is based on the chaotic tent map. Image encryption systems based on such map show some better performances. Firstly, the chaotic tent map is modified to generate chaotic key stream that is more suitable for image encryption. Secondly, the chaos-based key stream is generated by a 1-D chaotic tent map, which has a better performance in terms of randomness properties and security level. The performance and security analysis of the proposed image encryption scheme is performed using well-known ways. The results of the fail-safe analysis are inspiring, and it can be concluded that the proposed scheme is efficient and secure.

A novel image encryption scheme comprising of one permutation process and one diffusion process is proposed. In the permutation process, the image sized is expanded to one sized by dividing the plain-image into two parts: one consisting of the higher 4bits and one consisting of the lower 4bits. The permutation operations are done row-by-row and column-by-column to increase the speed. The chaotic generalized Arnold map is utilized to generate chaotic sequence, which is quantized to shuffle the expanded image. The chaotic sequence for permutation process is dependent on plain-image and cipher keys, resulting in good key sensitivity and plain-image sensitivity. To achieve more avalanche effect and larger key space, Chinese Remainder Theorem is applied to diffuse the shuffled image. The key sensitivity and key space of the proposed image encryption have been analyzed as well. The experimental results suggest that the proposed image encryption scheme can be used for secure image and video communication applications.

At present times the topic of Chaos gain a lot of attention for the encryption/decryption methodology, yet we didn’t settled to get a good difference between conventional counterparts. Several chaotic maps can be considered sensitivity dependence to seed values. Taking into consideration for this property, In this paper, the author have presented an image encryption technique employing a 2-dimensional chaotic Henon map, initially it implemented the confusion scheme using chaotic sequence obtained by several iterations using chaotic map approach. In the subsequent stage Edge Maps, generated by edge detection filters and binary bit plane decomposition is applied to perform further confusion using a bit-xor operation to get a cipher image. It is more secure and robust, experimental analysis and simulation is performed to get required results which better revealed that the encrypted images are secured and tolerant to different attacks.