• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권3호
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• pp.1078-1099
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• 2021

Traditional image steganography hides secret information by embedding, which inevitably leaves modification traces and is easy to be detected by steganography analysis tools. Since coverless steganography can effectively resist steganalysis, it has become a hotspot in information hiding research recently. Most coverless image steganography (CIS) methods are based on mapping rules, which not only exposes the vulnerability to geometric attacks, but also are less secure due to the revelation of mapping rules. To address the above issues, we introduced camouflage images for steganography instead of directly sending stego-image, which further improves the security performance and information hiding ability of steganography scheme. In particular, based on the different sub-features of stego-image and potential camouflage images, we try to find a larger similarity between them so as to achieve the reversible steganography. Specifically, based on the existing CIS mapping algorithm, we first can establish the correlation between stego-image and secret information and then transmit the camouflage images, which are obtained by reversible sub-feature retrieval algorithm. The received camouflage image can be used to reverse retrieve the stego-image in a public image database. Finally, we can use the same mapping rules to restore secret information. Extensive experimental results demonstrate the better robustness and security of the proposed approach in comparison to state-of-art CIS methods, especially in the robustness of geometric attacks.

• 한국정보통신학회논문지
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• 제25권10호
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• pp.1359-1368
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• 2021

스테가노그래피는 데이터 안에 데이터를 은폐하는 기술로, 전달 매체의 존재가 발각되지 않도록 하는 것이 주요목적이다. 현재 스테가노그래피 관련 연구는 알고리즘을 기반으로 정립된 은닉 기법, 검출 기법들에 관련해서 다양하게 연구되고 있지만, 소프트웨어 성능을 분석하기 위한 실험 중심의 연구는 상대적으로 부족하다. 본 논문은 서로 다른 알고리즘으로 데이터를 은폐하는 다섯 개의 스테가노그래피 소프트웨어의 특징을 파악하고, 평가하는 데 목적을 두었다. 스테가노그래피 소프트웨어의 성능 조사를 위하여 시각 평가 척도로 사용되는 PSNR(Peak Signal to Noise Ratio), SSIM(Structural SIMilarity)을 이용하였다. 스테가노그래피 소프트웨어를 통하여 임베딩한 스테고 이 미지들의 PSNR, SSIM을 도출하여 정량적 성능 비교 분석한다. 평가 척도에 따라 우수한 스테가노그래피 소프트웨어를 소개하여 포렌식에 기여 하고자 한다.

• ETRI Journal
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• 제36권3호
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• pp.479-489
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• 2014

This paper presents a model-based image steganography method based on Watson's visual model. Model-based steganography assumes a model for cover image statistics. This approach, however, has some weaknesses, including perceptual detectability. We propose to use Watson's visual model to improve perceptual undetectability of model-based steganography. The proposed method prevents visually perceptible changes during embedding. First, the maximum acceptable change in each discrete cosine transform coefficient is extracted based on Watson's visual model. Then, a model is fitted to a low-precision histogram of such coefficients and the message bits are encoded to this model. Finally, the encoded message bits are embedded in those coefficients whose maximum possible changes are visually imperceptible. Experimental results show that changes resulting from the proposed method are perceptually undetectable, whereas model-based steganography retains perceptually detectable changes. This perceptual undetectability is achieved while the perceptual quality - based on the structural similarity measure - and the security - based on two steganalysis methods - do not show any significant changes.

• Journal of Information Processing Systems
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• 제9권3호
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• pp.405-424
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• 2013

This research paper proposes a secured, robust approach of information security using steganography. It presents two component based LSB (Least Significant Bit) steganography methods for embedding secret data in the least significant bits of blue components and partial green components of random pixel locations in the edges of images. An adaptive LSB based steganography is proposed for embedding data based on the data available in MSB's (Most Significant Bits) of red, green, and blue components of randomly selected pixels across smooth areas. A hybrid feature detection filter is also proposed that performs better to predict edge areas even in noisy conditions. AES (Advanced Encryption Standard) and random pixel embedding is incorporated to provide two-tier security. The experimental results of the proposed approach are better in terms of PSNR and capacity. The comparison analysis of output results with other existing techniques is giving the proposed approach an edge over others. It has been thoroughly tested for various steganalysis attacks like visual analysis, histogram analysis, chi-square, and RS analysis and could sustain all these attacks very well.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권11호
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• pp.4184-4202
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• 2021

Text steganography combined with natural language generation has become increasingly popular. The existing methods usually embed secret information in the generated word by controlling the sampling in the process of text generation. A candidate pool will be constructed by greedy strategy, and only the words with high probability will be encoded, which damages the statistical law of the texts and seriously affects the security of steganography. In order to reduce the influence of the candidate pool on the statistical imperceptibility of steganography, we propose a steganography method based on a new sampling strategy. Instead of just consisting of words with high probability, we select words with relatively small difference from the actual sample of the language model to build a candidate pool, thus keeping consistency with the probability distribution of the language model. What's more, we encode the candidate words according to their probability similarity with the target word, which can further maintain the probability distribution. Experimental results show that the proposed method can outperform the state-of-the-art steganographic methods in terms of security performance.

• 방송공학회논문지
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• 제23권4호
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• pp.462-473
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• 2018

스테가노그래피란 숨기려는 정보를 미디어 데이터에 교묘하게 삽입하여 정보의 존재를 전혀 눈치 채지 못하도록 하는 데이터 은닉 기술의 하나이다. 데이터 암호화의 경우에는 정보 데이터에 직접 복호하기 어렵게 복잡한 부호화 기법을 이용하여 변형하는 것으로, 정보의 존재를 쉽게 인지할 수 있지만 복호를 어렵게 하는데 초점이 맞춰져 있다. 그러나 스테가노그래피는 다른 미디어에 정보를 자연스럽게 숨겨서 정보의 존재를 눈치 채지 못하게 함으로써, 더욱 강력하게 정보를 보호할 수 있다. 이 논문에서는 영상에 다른 영상 정보를 숨기는 영상 스테가노그래피의 개념을 소개하고, 스테가노그래피 부호화 여부를 판별하는 기법을 제안한다. 주로 영상 픽셀의 LSB (Least Significant Bit)를 조작하는 공간영역의 기법과, JPEG 압축시 DCT 계수를 조작하는 주파수 영역의 영상 스테가노그래피를 소개하고, 이들의 스테가노그래피 부호화 여부와 복호결과를 판별하는 새로운 방법을 제안한다.

• 정보보호학회논문지
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• 제32권4호
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• pp.723-736
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• 2022

스테가노그라피는 테러, 간첩 등 국가안보를 위협하는 범죄에 비밀통신 수단으로 활용되고 있다. 정보통신기술 발전에 따라 기술도 고도화되고 있고, 범죄자들은 자체적으로 프로그램을 제작하여 사용하고 있다. 하지만 스테가노그파리 관련내용이 공개되지 않아 수사기술 개발과 형사법적 대응에 한계가 있다. 따라서 본 논문에서는 스테가노그라피 수사를 위하여 탐지와 해독과정을 살펴보고 대법원에서 유죄판결 받은 김목사 간첩사건을 중심으로 수법을 분석하였다. 김목사 간첩사건은 사전에 약속된 스테고 키를 활용한 대칭 스테가노그라피를 사용하였고 다중보안장치를 사용한 고도화된 수법을 사용하고 있었다. 형사법적 쟁점은 ① 관련성, ② 참여권, ③ 공개재판 등 3가지 문제에 대하여 검토하였다. 본 연구가 수사기관이 스테가노그라피에 대한 분석기법을 발전시키는데 출발점이 되기를 기대한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권1호
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• pp.170-191
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• 2024

The transmission of confidential data using cover media is called steganography. The three requirements of any effective steganography system are high embedding capacity, security, and imperceptibility. The text file's structure, which makes syntax and grammar more visually obvious than in other media, contributes to its poor imperceptibility. Text steganography is regarded as the most challenging carrier to hide secret data because of its insufficient redundant data compared to other digital objects. Unicode characters, especially non-printing or invisible, are employed for hiding data by mapping a specific amount of secret data bits in each character and inserting the character into cover text spaces. These characters are known with limited spaces to embed secret data. Current studies that used Unicode characters in text steganography focused on increasing the data hiding capacity with insufficient redundant data in a text file. A sequential embedding pattern is often selected and included in all available positions in the cover text. This embedding pattern negatively affects the text steganography system's imperceptibility and security. Thus, this study attempts to solve these limitations using the Part-of-speech (POS) tagging technique combined with the randomization concept in data hiding. Combining these two techniques allows inserting the Unicode characters in randomized patterns with specific positions in the cover text to increase data hiding capacity with minimum effects on imperceptibility and security. Format-preserving encryption (FPE) is also used to encrypt a secret message without changing its size before the embedding processes. By comparing the proposed technique to already existing ones, the results demonstrate that it fulfils the cover file's capacity, imperceptibility, and security requirements.

• 한국산업정보학회논문지
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• 제20권3호
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• pp.29-36
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• 2015

스테가노그래피는 은닉되어 전송되는 비밀 메시지의 존재 자체를 숨기는 기술이다. 일반적으로 은닉 자료의 지각 투명성, 수용 능력, 견고성 등을 기반으로 하는 새롭고 정교한 스테가노그래피 기법을 개발하는 것이 주목적 이다. 이 논문에서는 이미지 스테가노그래피 기법의 장점과 단점을 분석하고, 효과적인 적용방법을 제시한다. 결과적으로 재배열키를 적용하고, 보안성이 좋은 ELSB와 DCT를 기반으로 하는 이미지 스테가노그래피 기법이 효과적이다.

• Journal of information and communication convergence engineering
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• 제15권3호
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• pp.151-159
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• 2017

Steganography, which is popular as an image processing technology, is the art of using digital images to hide a secret message in such a way that its existence can only be discovered by the sender and the intended receiver. This technique has the advantage of concealing secret information in a cover medium without drawing attention to it, unlike cryptography, which tries to convert data into something messy or meaningless. In this paper, we propose two efficient least significant bit (LSB)-based steganography techniques for designing an image-based steganography system on chip using hardware description language (HDL). The proposed techniques manipulate the LSB plane of the cover image to embed text inside it. The output of these algorithms is a stego-image which has the same quality as that of the original image. We also implement the proposed techniques using the Altera field programmable gate array (FPGA) and Quartus II design software.