• 한국멀티미디어학회논문지
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• 제18권4호
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• pp.483-491
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• 2015

Data hiding is one of protective methods that can authenticate the completeness of digital information and protect intelligent property rights and copyright through secret communications. In this paper, we propose a data hiding method using pixel-value modular operation that has a high capacity while maintaining a good visual quality. The proposed method can embed secret data on the every pixel of a cover image by modular operation. The experiment results demonstrate that the proposed method has a high capacity and good visual quality where the embedding capacity is 91,138 bytes, the PSNR is 47.94dB, and the Q index is 0.968.

• 한국멀티미디어학회:학술대회논문집
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• 한국멀티미디어학회 2002년도 춘계학술발표논문집(하)
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• pp.877-881
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• 2002

이미지와 같은 디지털 컨텐츠에 대한 저작권 보호 기능을 제공하기 위해서는 삽입된 워터마크에 대한 안전한 증명과 소유권에 대한 공개적인 검증 기술이 필요하다. 특히 워터마크된 컨텐츠에 비밀스럽게 은닉된 워터마크 정보에 대한 완전한 노출 없이도 증명하고자 하는 컨텐츠에 대한 소유권을 공개적으로 증명해 줄 수 있는 검증 기법이 필요하다. 본 연구에서는 기존의 영지식 증명 기법과 워터마킹 기법을 분석하였으며, 영지식 증명 기법을 디지털 워터마크 검증 구조에 적용하여, 워터마크에 대한 비밀정보 유출 없이도 소유권 및 저작권을 검증할 수 있는 영지식 기반 워터마크 검증 기법을 제시한다.

• 한국인터넷방송통신학회논문지
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• 제14권2호
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• pp.11-16
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• 2014

BTC는 단색 이미지 데이터의 압축을 위해서 사용되는 최근의 기술이다. BTC의 알고리즘은 평균과 표준편차를 사용하여 구현한다. 데이터 은닉을 위해, 이미지의 비트-구조를 변경하는 과정이 요구된다. 이러한 변경은 BTC 이미지의 질의 성능을 나쁘게 만든다. 따라서, 우리는 데이터 은닉의 성능 개선을 위해서 BTC를 개선한 IODBTC를 제한하였다. 실험 결과 복원한 비밀 메시지가 원본 비밀 메시지와 같음을 증명하였고 제안한 방법이 이전의 스킴에 비해서 좋은 BTC 이미지임을 증명하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권5호
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• pp.2258-2274
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• 2020

In this paper we first propose a new cryptosystem based on our data hiding scheme (2,9,8) introduced in 2019 with high security, where encrypting and hiding are done at once, the ciphertext does not depend on the input image size as existing hybrid techniques of cryptography and steganography. We then exploit our automata approach presented in 2019 to design two algorithms for exact and approximate pattern matching on secret data encrypted by our cryptosystem. Theoretical analyses remark that these algorithms both have O(n) time complexity in the worst case, where for the approximate algorithm, we assume that it uses ⌈(1-ε)m)⌉ processors, where ε, m and n are the error of our string similarity measure and lengths of the pattern and secret data, respectively. In searchable encryption, our cryptosystem is used by users and our pattern matching algorithms are performed by cloud providers.

• 한국산업정보학회논문지
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• 제17권5호
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• pp.37-42
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• 2012

오디오 스테가노그래피는 오디오 매체(신호)에 암호화된 비밀 메시지를 은닉하여 전송하는 일반적이고, 폭넓게 이용되는 통신기법이다. 인간은 청각시스템의 지각능력의 한계 때문에 커버 오디오 파일과 스테고 오디오 파일의 지각품질(perceptual quality) 차이는 없다. 또한 공격자로부터의 안전성과 견고성 측면에서 LSB 기법은 디지털화된 오디오 신호에 메시지를 삽입하는 효율적이고, 경제적인 방법으로 널리 이용되고 있다. 이 논문에서는 LSB 기법을 기반으로 하고, 디지털화된 비밀 메시지의 비트별 위치를 변경하고, 암호화한 후 커버 오디오 매체에 은닉하는 개선된 방법을 제시한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권2호
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• pp.945-958
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• 2017

This paper proposes a novel method of reversible data hiding in JPEG images. After analyzing the JPEG features, we provide a new algorithm of selecting appropriate blocks and coefficients to carry secret messages. Instead of embedding data into the histogram of all coefficients, we propose a strategy of ordered embedding to hide data by histogram shifts in several rounds. On the recipient end, secret messages can be exactly extracted, and the original JPEG image can be losslessly recovered. Experimental results show that high embedding rate can be achieved with limited distortions. Most importantly, the marked JPEG file generated by the proposed method requires less storage size than state-of-the-art works.

• Journal of Information Processing Systems
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• 제15권2호
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• pp.261-270
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• 2019

In order to protect secret digital documents against vulnerabilities while communicating, steganography algorithms are applied. It protects a digital file from unauthorized access by hiding the entire content. Pixel-value-difference being a method from spatial domain steganography utilizes the difference gap between neighbor pixels to fulfill the same. The proposed approach is a block-wise embedding process where blocks of variable size are chosen from the cover image, therefore, a stream of secret digital contents is hidden. Least significant bit (LSB) substitution method is applied as an adaptive mechanism and optimal pixel adjustment process (OPAP) is used to minimize the error rate. The proposed application succeeds to maintain good hiding capacity and better signal-to-noise ratio when compared against other existing methods. Any means of digital communication specially e-Governance applications could be highly benefited from this approach.

• International Journal of Computer Science & Network Security
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• 제22권7호
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• pp.383-388
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• 2022

Many methods used for secret data steganography are based on least significant bit method, which is suffering from security and the embedded message can be easily hacked. In this paper research a proposed method of adding security issues will be introduced, a complex private key will be constructed, the contents of this key will depend on the results of secrete message segmentation. The proposed method will be implemented and the obtained experimental results will be compared with least significant method results to prove that the proposed method raises the image quality parameters.

• Journal of Ubiquitous Convergence Technology
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• 제2권1호
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• pp.18-26
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• 2008

The invariance relation existing in the non-negative matrix factorization (NMF) is used for constructing robust image hashes in this work. The image is first re-scaled to a fixed size. Low-pass filtering is performed on the luminance component of the re-sized image to produce a normalized matrix. Entries in the normalized matrix are pseudo-randomly re-arranged under the control of a secret key to generate a secondary image. Non-negative matrix factorization is then performed on the secondary image. As the relation between most pairs of adjacent entries in the NMF's coefficient matrix is basically invariant to ordinary image processing, a coarse quantization scheme is devised to compress the extracted features contained in the coefficient matrix. The obtained binary elements are used to form the image hash after being scrambled based on another key. Similarity between hashes is measured by the Hamming distance. Experimental results show that the proposed scheme is robust against perceptually acceptable modifications to the image such as Gaussian filtering, moderate noise contamination, JPEG compression, re-scaling, and watermark embedding. Hashes of different images have very low collision probability. Tampering to local image areas can be detected by comparing the Hamming distance with a predetermined threshold, indicating the usefulness of the technique in digital forensics.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권11호
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• pp.2941-2956
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• 2013

In this paper, we propose an effective fragile image watermarking scheme for tampering detection and content recovery. Cover image is divided into a series of non-overlapping blocks and a block mapping relationship is constructed by the secret key. Several DCT coefficients with direct current and lower frequencies of the MSBs for each block are used to generate the reference bits, and different coefficients are assigned with different bit numbers for representation according to their importance. To enhance recovery performance, authentication bits are generated by the MSBs and the reference bits, respectively. After LSB substitution hiding, the embedded watermark bits in each block consist of the information of itself and its mapping blocks. On the receiver side, all blocks with tampered MSBs can be detected and recovered using the valid extracted reference bits. Experimental results demonstrate the effectiveness of the proposed scheme.