• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.155-158
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• 2008

In this paper, we propose a novel blind watermarking Method using 2D CAT (Two dimensional cellular automata transform). In our scheme, firstly, we obtain the gateway values to generate a dual-state, dual-coefficients basis function. Secondly, the basis function transforms images into cellular automata space. Lastly, we use the cellular automata transform coefficients to embed random noise watermark in the cover images. The proposed scheme allows only one 2D CAT basis function per gateway value. Since there are $2^{96}$ possible gateway values, better security is guaranteed. Moreover, the new method not only verifies higher fidelity than the existing method but also stronger stability on JPEG lossy compression, filtering, sharpening and noise through tests for robustness.

• Journal of information and communication convergence engineering
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• v.9 no.6
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• pp.689-694
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• 2011

Cellular automata are discrete dynamical systems, which provide the basis for the synthesis of complex emergent behavior. This paper proposes a new algorithm of digital watermarking based on cellular automata transform (CAT). The idea of two-dimensional CAT is introduced into the algorithm. After the original image is disassembled with 2D CAT, the watermark information is embedded into the Middle-frequency of the carrier picture. Cellular automata have a huge number of combinations, such as gateway values, rule numbers, initial configuration, boundary condition, etc. Using CAT, the robustness of the watermark will be tremendous strengthened as well as its imperceptibility. Experimental results show that this algorithm can resist some usual attacks such as compression, sharpening and so on. The proposed method is robust to different attacks and is more security.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.4
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• pp.34-41
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• 2009

In this paper we propose a new image encryption method which utilizes Complemented MLCA(Complemented Maximum Length Cellular Automata) based on IBCA(Intermediate Boundary CA) and 2D CAT(Cellular Automata Transform). The encryption method is processed in the following order. First, Complemented MLCA is used to create a PN (pseudo noise) sequence, which matches the size of the original image. And, the original image goes through a XOR operation with the created sequence to convert the image into Complemented MLCA image. Then, the gateway value is set to produce a 2D CAT basis function. The produced basis function is multiplied by the encrypted MLCA image that has been converted to process the encipherment. Lastly, the stability analysis and PSNR(Peak Signal to Noise Ratio) verifies that the proposed method holds a high encryption quality status.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.10
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• pp.2171-2179
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• 2009

In this paper, we propose a novel Image Encryption using MLCA (Maximum Length Cellular Automata) and CAT (Cellular Automata Transform). Firstly, we use the Wolfram rule matrix to generate MLCA state transition matrix T. Then the state transition matrix T changes pixel value of original image according to pixel position. Next, we obtain Gateway Values to generate 2D CAT basis function. Lastly, the basis function encrypts the MLCA encrypted image into cellular automata space. The experimental results and security analysis show that the proposed method guarantees better security and non-lossy encryption.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6C
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• pp.361-367
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• 2011

In this paper, we propose encryption method to using complemented MLCA(Maximum Length Cellular Automata) based on NBCA(Null Boundary CA) and 2D CAT (Two-Dimensional Cellular Automata Transform) for efficient image encryption. The encryption method is processed in the following order. First, a transition matrix T is created using the Wolfram Rule matrix. Then, the transition matrix T is multiplied to the original image that is intended to be encrypted, which transfers the pixel values of the original image. Furthermore, the converted original image goes through a XOR operation with complemented vector F to convert into a complemented MLCA applied image. Then, the gateway value is set and 2D CAT basis function is created. Also, the 2D CAT is encrypted by multiplying the created basis function to the complemented MLCA applied image. Lastly, the stability analysis verifies that proposed method holds a high encryption quality status.

• Proceedings of the Korea Multimedia Society Conference
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• 2012.05a
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• pp.332-335
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• 2012

본 논문에서는 CAT(Cellular Automata Transform) 성질을 이용하여 의료 영상의 단계적 변환을 제안한다. 적용 방법은 먼저, CAT 초기 값과 다양한 규칙에 따라 단계적으로 Gateway Values와 rule matrix에 대한 전이행렬 T를 이용하여 CAT 기저함수를 생성한다. 그런 다음, 생성된 CAT 기저함수를 의료 영상에 곱하여 영상을 다양한 방법으로 변환한다. 마지막으로, 키 공간 분석을 통하여 제안한 방법이 높은 영상 변환 및 보안의 성질을 가졌음을 검증한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.6
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• pp.1150-1156
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• 2009

In this paper, we propose the gradual encryption method of image using LFSR(Linear Feedback Shift Register) and 2D CAT(Two-Dimensional Cellular Automata Transform). First, an LFSR is used to create a PN(pseudo noise) sequence, which is identical to the size of the original image. Then the created sequence goes through an XOR operation with the original image resulting to the first encrypted image. Next, the gateway value is set to produce a 2D CAT basis function.The created basis function multiplied with the first encrypted image produces the 2D CAT encrypted image which is the final output. Lastly, the stability analysis verifies that the proposed method holds a high encryption quality status.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.164-167
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• 2009

In this paper, we propose the image encryption using LFSR(Linear Feedback Shift Register) and 2D CAT(Two-Dimensional Cellular Automata Transform). First, a LFSR is used to create a PN(pseudo noise) sequence, which is identical to the size of the original image. Then, the created sequence goes through a XOR operation with the original image to convert the original image. Next, the gateway value is set to produce a 2D CAT basis function. Using the created basis function, multiplication is done with the converted original image to process 2D CAT image encipherment. Lastly, the stability analysis verifies that the proposed method holds a high encryption quality status.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1C
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• pp.105-112
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• 2009

In this paper, we propose a digital watermarking method using Multi-resolution Characteristic of 2D CAT (2D cellular automata transform). Firstly, we select the gateway values to generate a basis function and the basis function transforms images into cellular automata space. Then, we embed the random bit sequence as watermark in specific parts of cellular automata transform coefficients. The proposed method not only verifies higher fidelity than the existing method but also stronger stability on JPEG lossy compression, filtering, sharpening and noise through tests for robustness. Moreover, the proposed scheme allows only one 2D CAT basis function per gateway value. Since there are $2^{96}$ possible gateway values.

• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.92-100
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• 2011

In this paper, we propose a novel blind digital watermarking method based on a cellular automata transform (CAT). CAT is based on dynamic systems known as cellular automata(CA) and uses transform bases which are differently defined by a rule number, the number of neighbors, the number of cells, and an initial state, etc. The proposed CAT based method is compared with a blind watermarking method based on DWT which is commonly used for a domain transform in signal processing. We analyse properties on changes of DWT coefficients and CAT coefficients under various attacks and determine optimal parameters for a watermarking method robust to attacks. The simulations show that the watermarked images with high PSNR and MSSIM look visually identical to originals and are robust against most of typical image processing attacks. Moreover, the proposed CAT based watermarking method is superior to the DWT based one in robustness to most of typical image processing attacks including JPEG compression, median and average filtering, scaling, cropping, and histogram equalization.