Elsevier

Journal of Systems and Software

Volume 97, November 2014, Pages 118-127
Journal of Systems and Software

Efficient implementation of chaotic image encryption in transform domains

https://doi.org/10.1016/j.jss.2014.07.026Get rights and content

Highlights

  • Investigation of transform domain encryption.

  • IWT encryption study.

  • Study of chaotic Baker map permutation.

Abstract

The primary goal of this paper is security management in data image transmission and storage. Because of the increased use of images in industrial operations, it is necessary to protect the secret data of the image against unauthorized access. In this paper, we introduce a novel approach for image encryption based on employing a cyclic shift and the 2-D chaotic Baker map in different transform domains. The Integer Wavelet Transform (IWT), the Discrete Wavelet Transform (DWT), and the Discrete Cosine Transform (DCT) are exploited in the proposed encryption approach. The characteristics of the transform domains are studied and used to carry out the chaotic encryption. A comparison study between the transform-domain encryption approaches in the presence of attacks shows the superiority of encryption in the DWT domain.

Introduction

The increasing demand for digital imaging applications, such as secure video conferences, military image communication and in general all confidential data transmission applications, has increased the need for reliable and effective security tools to protect important information in the images from attackers. Advantages of chaotic maps drew the attention of cryptographers to design robust encryption techniques. Sensitivity to initial conditions, mixing property, and ergodicity are the main properties of chaotic maps. These properties are similar to some of the cryptographic properties of ideal ciphers (for example, balance and confusion).

This paper presents an efficient cryptosystem, which is based on encrypting digital images in transform domains. The sophisticated advantage gained from the transform domains is the ability to transform correlated data patterns into transform domains to carry out the substitution or diffusion in these domains. This process can achieve a large degree of randomization, when returning back to the spatial domain.

The rest of this paper is organized as follows. Section 2 presents a review of the chaotic Baker map encryption algorithm. In Section 3, the design of the proposed chaos-based image cryptosystem is introduced. The visual inspection of the encryption results is given in Section 4. The security analysis of the proposed cryptosystem including the differential analysis, the statistical analysis, and the key-space analysis is presented in Section 5. Section 6 studies the effect of noise on the decryption process. In the last section, the concluding remarks are given.

Section snippets

Chaotic encryption

Chaotic cryptosystems rely on chaotic maps to encrypt images. They are extremely affected by the initial conditions. By using alternative parameters, the system works in different orbits that are hard to be computed and analyzed. The resulting sequences of these systems are characterized by low correlation, unpredictable, and good randomness.

The Baker map is a chaotic map, which randomizes a unit square using a 2-D mapping process. Its operation is breaking the square in half, and the two

The proposed encryption algorithm

The proposed encryption scheme contains two main stages; a cyclic shift and 2-D chaotic Baker map encryption in a transform domain. The cyclic shift is accomplished with a secret key, which can be generated using a Pseudo-Number PN sequence generator. The secret key is used at the transmitter and the receiver. The generated key controls the permutation process. Firstly, row permutation takes place in the original image. If a key bit equals 1, the whole corresponding row is circularly shifted to

Visual inspection of the proposed chaotic image cryptosystem

Several experiments have been carried out in different transform domains in order to investigate the efficiency of the proposed chaotic image cryptosystem. The proposed chaotic image cryptosystem has been implemented using the 2-D Baker map with a cyclic shift on the transformed image with a single key for the DCT, and multiple similar or different keys for the IDWT and DWT. The original Lena image is shown in Fig. 4a, and the encrypted images resulting from the proposed chaotic image

Experimental analysis

The encryption technique should survive attacks such as various brute-force attacks, ciphertext only attack, plaintext attack, differential attack, and statistical attacks (Li et al., 2002). Here, we will examine the proposed cryptosystem in transform domains in the presence of statistical attacks, differential attacks, and brute-force attack (Zhai et al., 2008). Some results of the security analysis for each attack process are presented.

Effect of noise

We have tested the robustness of the proposed chaotic cryptosystem to the presence of noise in the decryption process. To judge the quality of the decrypted image at the detector, the Peak Signal-to-Noise Ratio (PSNR) is used. It is calculated as follows:PSNR=10logW×H(255)2i=0H1j=0W1(f1(i,j)f2(i,j))2where f1(i, j) is the pixel value of the original image at position (i, j), and f2(i, j) is the pixel value of the received image at position (i, j). Of course, the higher value of the PSNR

Conclusion

The importance of securing digital images has become a necessity since images are frequently transmitted via open networks. In this paper, an efficient chaotic image cryptosystem in transform domains has been presented. This algorithm is based on implementing cyclic shifts in the transform domains prior to the application of the 2-D chaotic Baker map. Both the cyclic shifts and the 2-D Baker map achieve a large degree of permutation prior to the inverse transform, which achieves a diffusion

Ensherah A. Naeem graduated from the Faculty of Engineering, Tanta University, Egypt in 2006. She is now a web developer and M.Sc. student. Her interest is in security over wired and wireless networks and image processing.

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Ensherah A. Naeem graduated from the Faculty of Engineering, Tanta University, Egypt in 2006. She is now a web developer and M.Sc. student. Her interest is in security over wired and wireless networks and image processing.

Mustafa M. Abd Elnaby is the head of Electronics and communications Engineering Dept., college of Engineering, Tanta University, Egypt. Since 2001, he has been a Professor of electrical engineering at University of Qatar, Qatar. Prof. Mustafa was a visiting Professor at Kyushu University, Japan, working in design and fabrication of MOS devices for flash memory and communication systems applications. He has also served as a Visiting Professor at Aachen University.

Naglaa F. Soliman received the B.Sc., M.Sc., and Ph.D. degrees from the faculty of Engineering, Zagazig University, Egypt in 1999, 2004, and 2011, respectively. She is currently a lecturer at the Department of Electronics and Communications Engineering, Faculty of Engineering, Zagazig University. Her areas of interest are digital communications, signal processing, image processing, and coding.

Alaa M. Abbas is a lecturer at the Department of Electronics and Electrical Communications, Faculty of Electronic Engineering, Menofia University. He received his B.Sc., M.Sc., and Ph.D. degree in electrical engineering from Menofia University, Egypt, in 1996, 2001, and 2008, respectively. His areas of interest include digital signal processing, image processing, motion estimation, pattern recognition, and face detection and recognition.

Osama S. Faragallah received the B.Sc., M.Sc., and Ph.D. degrees in computer science and engineering from Menoufia University, Menouf, Egypt, in 1997, 2002, and 2007, respectively. He is currently with the Department of Computer Science and Engineering, Faculty of Electronic Engineering, Menoufia University, where he was a Demonstrator from 1997 to 2002 and has been a Lecturer in 2007. He is currently an associate professor. His research interests cover computer networks, network security, cryptography, Internet security, multimedia security, image encryption, watermarking, steganography, data hiding, and chaos theory.

Noura Semary is a lecturer at Information Technology Department, Faculty of Computers and Information, Menofia University. She received her B.Sc. degree in computers and information technology, Cairo University, in 2001. She received her M.Sc. and Ph.D. in computers and information technology, Menofia University, in 2007 and 2011 respectively. Her research interests include image and video processing, computer vision, data compression, virtual reality and pattern recognition fields.

Mohiy M. Hadhoud has received the B.Sc. (Hons) and M.Sc. degrees from the Faculty of Electronic Engineering, Menoufia University, Menouf, Egypt, in 1976 and 1981, respectively, and the Ph.D. degree from Southampton University in 1987. He joined the teaching staff of the Department of Electronics and Electrical Communications, Faculty of Electronic Engineering, Menoufia University, Menouf, Egypt from 1981 to 2001. He is currently a professor in the Dept. of Information Technology, Faculty of Computers and Information, Menoufia University, Shiben El-Kom. He has published more than one hundred scientific papers in national and international conferences and journals. His current research areas of interest include adaptive signal and image processing techniques, image enhancement, image restoration, superresolution reconstruction of images, data hiding and image coloring.

Saleh A. Alshebeili is professor and chairman (2001–2005) of Electrical Engineering Department, King Saud University. He has more than 20 years of teaching and research experience in the area of communications and signal processing. Dr Alshebeili is member of the board of directors of Prince Sultan Advanced Technologies Research Institute (PSATRI), the Vice President of PSATRI (2008–2011), the director of Saudi-Telecom Research Chair (2008–2012), and the director (2011–Present) of the Technology Innovation Center, RF and Photonics in the e-Society (RFTONICS), funded by King Abdulaziz City for Science and Technology (KACST). Dr Alshebeili has been in the editorial board of Journal of Engineering Sciences of King Saud University (2009–2012). He has also an active involvement in the review process of a number of research journals, KACST general directorate grants programs, and national and international symposiums and conferences.

Fathi E. Abd El-Samie received the B.Sc. (Hons.), M.Sc., and Ph.D. degrees from Menoufia University, Menouf, Egypt, in 1998, 2001, and 2005, respectively. Since 2005, he has been a Teaching Staff Member with the Department of Electronics and Electrical Communications, Faculty of Electronic Engineering, Menoufia University. He is currently a researcher at KACST-TIC in Radio Frequency and Photonics for the e-Society (RFTONICs). He is a coauthor of about 200 papers in international conference proceedings and journals, and five textbooks. His current research interests include image enhancement, image restoration, image interpolation, super-resolution reconstruction of images, data hiding, multimedia communications, medical image processing, optical signal processing, and digital communications. Dr. Abd El-Samie was a recipient of the Most Cited Paper Award from the Digital Signal Processing journal in 2008.

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