• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.1-8
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• 2002

Digital image watermarking is a technique for the purpose of protecting the ownership of the image by embedding proprietary watermarks in a digital image. It is required for the digital image watermarking scheme to pursue the robustness against water marking attacks and the perceptual Invisibility more than usual in steganography area, to guarantee not a hidden watermarking algorithm but the publicity of water-marking algorithm details and hidden use of key, which can protect the unauthorized user access from detection. In this paper we propose a new copyright watermarking scheme, which is barred on one-way hash functions using ElGamal functions and modular operations. ElGamal functions are widely used in cryptographic systems. Our watermarking scheme is robust against LSB(least significant bit) attacks and gamma correction attack, and also perceptually invisible. We demonstrate the characteristics of our proposed watermarking scheme through experiments. It is necessary to proceed as the future work the algorithm of achieving at the same time both the pseudo-randomness for the steno-key generation and the asymmetric-key generation.

• Journal of Broadcast Engineering
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• v.24 no.2
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• pp.315-328
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• 2019

Image steganalysis is an algorithm that classifies input images into stego images with steganography methods and cover images without steganography methods. Previously, handcrafted feature-based steganalysis methods have been mainly studied. However, CNN-based objects recognition has achieved great successes and CNN-based steganalysis is actively studied recently. Unlike object recognition, CNN-based steganalysis requires preprocessing filters to discriminate the subtle difference between cover images from stego images. Therefore, CNN-based steganalysis studies have focused on developing effective preprocessing filters as well as network structures. In this paper, we compare previous studies in same experimental conditions, and based on the results, we analy ze the performance variation caused by the differences in preprocessing filter and network structure.

• Journal of the Korea Society of Computer and Information
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• v.27 no.7
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• pp.17-25
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• 2022

Hash functions are widely used for fast equality analysis of video files because of their fixed small output sizes regardless of their input sizes. However, the hash function has the possibility of a hash collision in which different inputs derive the same output value, so there is a problem that different video files may be mistaken for the same file. In this paper, we propose an equality analysis scheme in which different video files always derive different output values using identifier information and double hash. The scheme first extracts the identifier information of an original video file, and attaches it into the end of the original file with a steganography method. Next the scheme calculates two hash output values of the original file and the extended file with attached identifier information. Finally the scheme utilizes the identifier information, the hash output value of the original file, and the hash output value of the extended file for the equality analysis of video files. For evaluation, we implement the proposed scheme into a practical software tool and show that the proposed scheme performs well the equality analysis of video files without hash collision problem and increases the resistance against the malicious hash collision attack.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.3
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• pp.1051-1077
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• 2021

The secure communication of information is a major concern over the internet. The information must be protected before transmitting over a communication channel to avoid security violations. In this paper, a new hybrid method called compressed encrypted data embedding (CEDE) is proposed. In CEDE, the secret information is first compressed with Lempel Ziv Welch (LZW) compression algorithm. Then, the compressed secret information is encrypted using the Advanced Encryption Standard (AES) symmetric block cipher. In the last step, the encrypted information is embedded into an image of size 512 × 512 pixels by using image steganography. In the steganographic technique, the compressed and encrypted secret data bits are divided into pairs of two bits and pixels of the cover image are also arranged in four pairs. The four pairs of secret data are compared with the respective four pairs of each cover pixel which leads to sixteen possibilities of matching in between secret data pairs and pairs of cover pixels. The least significant bits (LSBs) of current and imminent pixels are modified according to the matching case number. The proposed technique provides double-folded security and the results show that stego image carries a high capacity of secret data with adequate peak signal to noise ratio (PSNR) and lower mean square error (MSE) when compared with existing methods in the literature.

• The KIPS Transactions:PartC
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• v.15C no.3
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• pp.149-156
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• 2008

JPEG2000 is the upcoming image coding standard that provides better compression rate and image quality compared with JPEG. Lazy-mode steganography guarantees the safe communication under the two information loss stages in JPEG2000. However, it causes the severe changes of the code-block noise variance sequence after embedding and that is detectable under the steganalysis using the Hilbert-Huang transform (HHT) based sequential analysis. In this paper, a JPEG2000 lazy-mode steganography method is presented. The code blocks which produce the sudden variation of the noise variance after embedding are estimated by calculating low precision code-block variance (LPV) and low precision code-block noise variance (LPNV). By avoiding those code-blocks from embedding, our algorithm preserves the sequence and makes stego images secure under the HHT-based steganalytic detection. In addition, it prevents a severe degradation of image quality by using JPEG2000 quality layer information. On various 2048 images, experiments are performed to show the effective reduction of the noise variation after message embedding and the stable performance against HHT-based steganalysis.

• Proceedings of the Korea Multimedia Society Conference
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• 1998.04a
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• pp.210-215
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• 1998

암호 통신의 한 방법으로 표면상의 의미 있는 형태를 유지하지만 실은 그 속에 중요한 기밀 정보를 숨겨놓은 심층암호(steganography)가 주목되고 있으며, 특히 디지털 화상을 이용하는 화상 심층암호는 저작권 보호 수단으로 활용되고 있다. 본 논문은 농담화상을 오차 확산법을 이용하여 흑·백의 2치로 의사적으로 표시하면서 기밀 정보를 합성하는 새로운 방식을 제안한다.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.250-253
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• 2006

In this paper, we proposed a new method of the Adaptive steganography using complexity on bit planes of color image. Applying fixing threshold and variable length, if insert information into all bit plans, all bit plans showed different image quality. Therefore, we first defined the complexity on bit plane and data complexity, similarity insert information into bit plans. As a result, the proposed method increased the insertion capacity and improved the image quality than fixing threshold and variable length method.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2016.06a
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• pp.231-234
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• 2016

본 논문에서는 전송하고자 하는 원영상 대신에 전혀 다른 영상을 전송하여 원영상 정보를 보호하는 스테가노그래피(steganography) 기법을 제안한다. 전송할 영상의 자연스러움을 잃어버리지 않으면서 원영상을 복구할 수 있는 차영상 정보를 LSB(Least Significant Bit)에 담고, 픽셀간의 위치 관계를 무작위로 섞어 줌으로써, 원영상을 보호하는 기법을 제안한다. 본 논문에서는 우선 원영상과 전송할 영상 (cover image)의 차영상을 생성하고, 각 픽셀의 차이값을 큰 범위로 양자화하여 차영상의 데이터 크기를 줄인다. 그리고, 각 픽셀의 차이값을 전송할 영상의 4 픽셀에 걸쳐서 하위 2bit 에 나누어 담는다. 8bit 영상에서 하위 2 bit 를 다루기 때문에, 각 채널 밝기값의 최대 차이값은 3 으로 설정되어 자연스럽게 영상을 생성할 수 있다. 끝으로 신호의 보호를 위하여 차영상의 픽셀과 전송할 영상의 픽셀간의 대응위치를 무작위 순열로 변환하여 외부에서 쉽게 복원할 수 없도록 한다. 이러한 스테가노그래피 제안 기법을 통하여 원영상 대신에 커버 영상을 전송함으로써, 자연스러운 정보전송이 가능하며, 외부의 감시와 복원에 안전한 정보보호 기능이 강화될 수 있다. 여러 영상에 대한 실험을 통한 제안 기법에 의하면, 전송되는 커버 영상이 자연스럽기 때문에 외부에서 정보가 숨겨진 사실을 느끼지 못하며, 송수신 장치에 내장된 무작위 순열을 통하여 외부에서는 원영상 정보를 복구하는 것도 매우 어렵게 되어 있음을 확인하였다. 본 제안 기법은 군사통신이나 중요한 정보를 다루는 기관에서의 정보 전달 및 정보보호 시스템에서 사용될 수 있다.

• The Transactions of the Korea Information Processing Society
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• v.4 no.1
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• pp.11-22
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• 1997

The fractal image compression partitions an original image into blocks of equal size and searches a do-main block having self-similarity. This method of compression achieves high compression ratio because it is unnecessary to transmit the additional codebook to receiver and it provides good quality of reconstructed images. In spite of these advantages, this method has a drawback in which encoding time increase due to a complicated linear transformation for determining a similar-domain block. In this paper, a fast fractal image compression method is proposed by decreasing the number of transformation usings AC(alternating current) coefficients of block. The proposed method also has a good quality as compared with the well-known fractal codings. Furthermore, method also has a good quality as apply the video steganography that can conceal an important secret data.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.4
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• pp.684-690
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• 2009

In this paper, we proposed a new method of the steganography based on bit plane using similarity. Applying a fixed threshold, the insert information into all bit planes showed different image quality. Therefore, we first defined the bit plane of block similarity to solve the fixing threshold problem. We then proposed a new method using the Bit Plane complexity and similarity to insert information into bit planes of block. In the experiment, we inserted information into the standard images with the same image quality and same insertion capacity. Finally analyzed the insertion capacity and image quality. As a result, the proposed method increased the insertion capacity of about 6% and improved the image quality of about 3.3dB than fixing threshold method.