• Journal of Computing Science and Engineering
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• v.8 no.4
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• pp.187-198
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• 2014

In this paper an efficient image encryption scheme based on cyclic rotations and multiple blockwise diffusions with two chaotic maps is proposed. A Sin map is used to generate round keys for the encryption/decryption process. A Pomeau-Manneville map is used to generate chaotic values for permutation, pixel value rotation and diffusion operations. The encryption scheme is composed of three stages: permutation, pixel value rotation and diffusion. The permutation stage performs four operations on the image: row shuffling, column shuffling, cyclic rotation of all the rows and cyclic rotation of all the columns. This stage reduces the correlation significantly among neighboring pixels. The second stage performs circular rotation of pixel values twice by scanning the image horizontally and vertically. The amount of rotation is based on $M{\times}N$ chaotic values. The last stage performs the diffusion four times by scanning the image in four different ways: block of $8{\times}8$ pixels, block of $16{\times}16$ pixels, principal diagonally, and secondary diagonally. Each of the above four diffusions performs the diffusion in two directions (forwards and backwards) with two previously diffused pixels and two chaotic values. This stage makes the scheme resistant to differential attacks. The security and performance of the proposed method is analyzed systematically by using the key space, entropy, statistical, differential and performance analysis. The experimental results confirm that the proposed method is computationally efficient with high security.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.6
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• pp.1469-1475
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• 2010

This paper presents a problem of existing encryption methods using pseudo-random numbers based on MLCA or complemented MLCA and proposes a method to resolve this problem. The existing encryption methods have a problem which the edge of original image appear on encrypted image because the image have color similarity of adjacent pixels. In this proposed method, we transform the value and spatial coordinates of all pixels by using pseudo-random numbers based on MLCA. This method can resolve the problem of existing methods and improve the level of encryption by encrypting pixel coordinates and pixel values of original image. The effectiveness of the proposed method is proved by conducting histogram and key space analysis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1C
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• pp.51-58
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• 2007

The purpose of this paper is to find an efficient encryption scheme for digital holograms (fringe patterns) with low encryption cost. Therefore, we introduced several encryption attempts in both hologram-domain and frequency-domain (both DCT-domain and DWT-domain) on the bases of the results from analyzing the properties of the coefficients in each domain. To effectively hide the image information, 25%, 1.5625%, and 0.0244% of the original fringe pattern need to be encrypted for hologram-domain scheme, DWT-domain scheme, and DCT-domain scheme, respectively. Consequently the DCT-domain scheme was the most efficient and it is caused by the fact that the ability for DCT to concentrate the energy of a given 2-dimensional image into a small area is the best. The encryption schemes and the analyses in this paper are expected to be used effectively on the researches on encryption and others for digital holograms.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.4
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• pp.9-21
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• 2004

In this paper, we proposed the image hiding method which decreases calculation amount by encrypt partial data using discrete wavelet transform and linear scale quantization which were adopted as the main technique for frequency transform in JPEG2000 standard. Also we used the chaotic system which has smaller calculation amount than other encryption algorithms and then dramatically decreased calculation amount. This method operates encryption process between quantization and entropy coding for preserving compression ratio of images and uses the subband selection method and the random changing method using the chaotic system. For ciphering the quantization index we use a novel image encryption algerian of cyclically shifted in the right or left direction and encrypts two quantization assignment method (Top-down/Reflection code), made change of data less. Also, suggested encryption method to JPEG2000 progressive transmission. The experiments have been performed with the proposed methods implemented in software for about 500 images. consequently, we are sure that the proposed are efficient image encryption methods to acquire the high encryption effect with small amount of encryption. It has been shown that there exits a relation of trade-off between the execution time and the effect of the encryption. It means that the proposed methods can be selectively used according to the application areas. Also, because the proposed methods are performed in the application layer, they are expected to be a good solution for the end-to-end security problem, which is appearing as one of the important problems in the networks with both wired and wireless sections.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.152-155
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• 2009

In this paper, we propose the image encryption method using complemented MLCA based on 90/150 NBCA(Null Boundary Cellular Automata). The encryption method is processed in the following order. First, complemented MLCA, which is derived from linear LFSR, is used to produce a PN(pseudo noise) sequence, which matches the size of the original image. Then, the created complemented MLCA sequence goes through a XOR operation with the original image to become encrypted. Lastly, an experiment is processed to verify the effectiveness of this method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.4
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• pp.1307-1329
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• 2022

This paper proposes an improved Pseudorandom Sequence Generator (PRSG) based on the concept of modular arithmetic systems with non-integral numbers. The generated random sequence use in various cryptographic applications due to its unpredictability. Here the mathematical model is designed to solve the problem of the non-uniform distribution of the sequences. In addition, PRSG has passed the standard statistical and empirical tests, which shows that the proposed generator has good statistical characteristics. Finally, image encryption has been performed based on the sort-index method and diffusion processing to obtain the encrypted image. After a thorough evaluation of encryption performance, there has been no direct association between the original and encrypted images. The results show that the proposed PRSG has good statistical characteristics and security performance in cryptographic applications.

• Computers and Concrete
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• v.34 no.1
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• pp.79-91
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• 2024

In symmetric cryptography, a cryptographically secure Substitution-Box (S-Box) is a key component of a block cipher. S-Box adds a confusion layer in block ciphers that provide resistance against well-known attacks. The generation of a cryptographically secure S-Box depends upon its generation mechanism. In this paper, we propose a novel framework for the construction of cryptographically secure S-Boxes. This framework uses a combination of linear fractional transformation and permutation functions. S-Boxes security is analyzed against well-known security criteria that include nonlinearity, bijectiveness, strict avalanche and bits independence criteria, linear and differential approximation probability. The S-Boxes can be used in the encryption of any grayscale digital images. The encrypted images are analyzed against well-known image analysis criteria that include pixel changing rates, correlation, entropy, and average change of intensity. The analysis of the encrypted image shows that our image encryption scheme is secure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5C
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• pp.497-502
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• 2006

In this paper, we propose a digital image encryption method using adaptive interleaving and multiple random shuffling table to improve the existing encryption methods which use a fixed random shuffling table. In order to withstand the plaintext attack, at first, we propose a interleaving method that is adaptive to the local feature of image. Secondly, using the proposed interleaving only shuffling method and multiple shuffling method that is combined interleaving with existing random shuffling method, we encrypted image by shuffled the DPCM processed $8^*8$ blocks. Experimental results show that, the proposed algorithm is very robust to plaintext attack and there is no overhead bit.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1117-1124
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• 2023

The security of information, including image content, is an essential part of today's communications technology and is critical to secure transmission. In this paper, a new ROI-based image encryption algorithm is proposed that can quickly encrypt images with a security level suitable for environments that require real-time data transmission for images containing sensitive information such as ID cards. The proposed algorithm is based on one dimensional 5-neighbor cellular automata, which can be implemented in hardware and performed hardware-friendly operations. Various experiments and analyses are performed to verify whether the proposed encryption algorithm is safe from various brute-force attacks.

• Journal of the Optical Society of Korea
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• v.6 no.4
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• pp.156-160
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• 2002

In this paper, we propose an improved optical security system using three phase-encoded images and the principle of interference. This optical system based on a Mach-Zehnder interferometer consists of one phase-encoded virtual image to be encrypted and two phase-encoded images, en-crypting image and decrypting image, where every pixel in the three images has a phase value of '0'and'$\pi$'. The proposed encryption is performed by the multiplication of an encrypting image and a phase-encoded virtual image which dose not contain any information from the decrypted im-age. Therefore, even if the unauthorized users steal and analyze the encrypted image, they cannot reconstruct the required image. This virtual image protects the original image from counterfeiting and unauthorized access. The decryption of the original image is simply performed by interfering between a reference wave and a direct pixel-to-pixel mapping image of the en crypted image with a decrypting image. Computer simulations confirmed the effectiveness of the proposed optical technique for optical security applications.