Peyman Ayubi

Bio: Peyman Ayubi is an academic researcher from Islamic Azad University. The author has contributed to research in topics: Digital watermarking & Key space. The author has an hindex of 13, co-authored 27 publications receiving 382 citations.

A new transform domain steganography based on modified logistic chaotic map for color images

Abstract: The art and science of hiding information by embedding messages in various type of digital media is called steganography. This method performs by replacing bits of multimedia files (such as graphics, sounds and texts) with bits of secret message. The information that embeds in the cover media can be plain text, cipher text and even images. Steganography sometimes is used when encryption is not permitted or more commonly, steganography is supplement for encryption. By using steganography, if the encrypted file is deciphered, the encrypted file may still hide information. This paper is proposed a new transform domain steganography method based on integer wavelet transform (IWT) for digital images and also it used a chaotic map. This map is a modified logistic map which it increases the key length and security of proposed method. Experimental results shows that the proposed method has high capability in hiding information in any images which used as a cover media. Visual quality of image after embedding process is desirable due to Peak Signal-to-Noise Ratio (PSNR) measures. Also the NIST, DIEHARD and ENT tests suite show the proposed chaotic map randomness and sensitivity to smallest changes.

An integer wavelet transform image steganography method based on 3D sine chaotic map

Abstract: Steganography is one of the well-known data hiding methods, which is used in many security companies and government communications. In this technique, the various types of digital media can be used as a cover to hide secret information without impress the general form of them. Generally, key space and security are two important matters in most steganography methods, and they have the direct impact in proposed method’s security. Moreover, Chaotic maps have been used in many data hiding algorithms to increase the security and key space of proposed schemes. The main reasons of using chaotic maps in steganography methods are sensitivity to initial conditions and control parameters. This paper proposes a new steganography technique based on new 3d sine chaotic map. This map is used in embedding and extracting processes to increase the security of the proposed algorithm. Satisfactory performance, acceptable image distortion and stronger robustness against some attacks are the main features of proposed method, and they are shown in experimental results. Comparison with some existing method shows that the quality and performance of the proposed algorithm are good, and it has high security and acceptable robustness against cropping and salt & pepper attacks.

Digital image scrambling based on a new one-dimensional coupled Sine map

Abstract: This paper proposes a new one-dimensional chaotic map, called chaotic coupled Sine map (CCSM), for the scrambling and encryption processes. The purpose of the CCSM design is to increase the security of the key space relative to the basic maps, such as Logistic map and Sine map. Bifurcation diagram and Lyapunov exponent analysis showed that the proposed map is fully chaotic and can be used as a secure pseudo-random number generator in encryption systems. Furthermore, to increase the flexibility of the proposed method, a dynamic algorithm based on the size of blocks is used in the scrambling process. To compare the proposed method and some similar schemes, a simple encryption process is used. The simulation results of this algorithm are evaluated based on security and performance analysis criteria. The comparison results show that the suggested technique has better performance in terms of security and visual quality measure.

Deterministic chaos game: A new fractal based pseudo-random number generator and its cryptographic application

Abstract: In this paper, a digital image encryption algorithm is proposed based on the generalized model of the chaos game. The chaos game is a well-known fractal, which acts as a pseudo-random number generator (PRNG) in the proposed encryption algorithm. The foundation of the chaos game is based on basic points and its distance ratio that determine the basis of how they distribute random values in 2D or 3D space. These basic points are entered by the user interface and are the result of an encrypted image with a fractal structure. The use of the bifurcation diagram and Lyapunov exponent analysis showed that the proposed chaos game has the dynamical behavior, and fully chaotic characteristic, and can be used as a secure PRNG in cryptography systems. In the proposed method, the region of interest is determined by a number of Bases, and the fractal mechanism of chaos game for the encryption process is performed on the image. This process is very sensitive to any changes in keys and refers to confusion. The evaluation results of security and performance analysis on standard images confirm the efficiency of the proposed method and demonstrate that the proposed method is robust against attacks.

An Introduction to Chaos in Nonequilibrium Statistical Mechanics

Abstract: Preface 1. Non-equilibrium statistical mechanics 2. The Boltzmann equation 3. Liouville's equation 4. Poincare recurrence theorem 5. Boltzmann's ergodic hypothesis 6. Gibbs' picture-mixing systems 7. The Green-Kubo formulae 8. The Baker's transformation 9. Lyapunov exponents for a map 10. The Baker's transformation is ergodic 11. Kolmogorov-Sinai entropy 12. The Frobenius-Perron equation 13. Open systems and escape-rates 14. Transport coefficients and chaos 15. SRB and Gibbs measures 16. Fractal forms in Green-Kubo relations 17. Unstable periodic orbits 18. Lorentz lattice gases 19. Dynamical foundations of the Boltzmann equation 20. The Boltzmann equation returns 21. What's next Appendices Bibliography.

Dynamic Analysis of Digital Chaotic Maps via State-Mapping Networks

Abstract: Chaotic dynamics is widely used to design pseudo-random number generators and for other applications such as secure communications and encryption. This paper aims to study the dynamics of discrete-time chaotic maps in the digital (i.e., finite-precision) domain. Differing from the traditional approaches treating a digital chaotic map as a black box with different explanations according to the test results of the output, the dynamical properties of such chaotic maps are first explored with a fixed-point arithmetic, using the Logistic map and the Tent map as two representative examples, from a new perspective with the corresponding state-mapping networks (SMNs). In an SMN, every possible value in the digital domain is considered as a node and the mapping relationship between any pair of nodes is a directed edge. The scale-free properties of the Logistic map's SMN are proved. The analytic results are further extended to the scenario of floating-point arithmetic and for other chaotic maps. Understanding the network structure of a chaotic map's SMN in digital computers can facilitate counteracting the undesirable degeneration of chaotic dynamics in finite-precision domains, helping also classify and improve the randomness of pseudo-random number sequences generated by iterating chaotic maps.

A novel chaos-based fragile watermarking for image tampering detection and self-recovery

Abstract: In this paper, a novel watermarking approach is proposed to provide enhanced tampering localization and self-recovery. A cross chaotic map is used to confuse the blocks generated by the original image. A sister block embedding scheme is proposed to improve the recovery effect after tampering. Flags and a combination of the most significant bit (MSB) and the least significant bit (LSB) mechanism are applied to improve the tampering detection rate and the defense of attacks. And an optimization scheme is given to make the recovered image have advanced visual effects. Experiment results show that the proposed schemes are more secure and have better effect on tampering detection and recovery even though the tampered area is relatively large.

An image fragile watermark scheme based on chaotic image pattern and pixel-pairs

Abstract: Fragile watermarking techniques for digital content have been studied in the past few years. Fragile watermarks are used to determine if a piece of watermarked digital content has been tampered, and distinguish tampered areas from non-tampered areas without referring to the original digital content. In this paper, a general framework for fragile watermark is proposed, and then a novel fragile watermarking scheme for image authentication is presented. The embedding process of fragile watermark starts from computing the difference image between the host image and its chaotic pattern. followed by mapping the difference image into a binary image. The binary image is then inserted into the least significant bit (LSB) bitplane of the host image. In addition, chaotic map is used to generate the chaotic pattern image, which can be used as secret key to improve the security of watermark algorithm. Due to employing permutation transform and chaotic image pattern, the corresponding position relation is broken between pixels in the watermarked image and the watermark. Simulation results and performance analysis show that the presented method is fast, secure and capable of detecting and localizing modification.