• 한국컴퓨터정보학회논문지
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• 제21권2호
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• pp.33-42
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• 2016

In this paper, an advanced reversible data hiding algorithm which takes the advantage of the spatial locality in image was proposed. Natural image has a spatial locality. The pixel value of a natural image is similar to the values of neighboring pixels. So, using the neighboring pixel values, it is possible to precisely predict the pixel value. Frequency increases significantly at the peak point of the difference histogram using the predicted values. Therefore, it is possible to increase the amount of data to be embedded. By using the proposed algorithm, visually high quality stego-image can be generated, the original cover image and the embedded data can be extracted from the stego-image without distortion. The embedding data into the cover image of the proposed algorithm is much lager than that of the previous algorithm. The performance of the proposed algorithm was verified by experiment. The proposed algorithm is very useful for the reversible data hiding.

• International Journal of Internet, Broadcasting and Communication
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• 제13권3호
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• pp.50-55
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• 2021

In this paper, we proposed a technique for hiding the double-encrypted confidential data in the image using the pixel value of the image and the spatial encryption technique. The proposed technique inserts encrypted confidential data into the LSB of an image pixel in order to maintain high image quality. The stego-image generated by hiding the encrypted confidential data has very good quality and is visually indistinguishable from the original cover image, so that it is impossible to recognize whether the confidential data is hidden in the stego-image. It is possible to extract the original confidential data from the stego-image without loss. By conducting an experiment on the proposed technique, it was confirmed that the proposed technique is an effective technique for the practical application of data hiding. The proposed technique can be used in applications such as military and intellectual property protection that require high security.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권8호
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• pp.1964-1981
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• 2012

In this paper a reversible data hiding scheme based on histogram shifting of host image blocks is presented. This method attempts to use full available capacity for data embedding by dividing the image into non-overlapping blocks. Applying histogram shifting to each block requires that extra information to be saved as overhead data for each block. This extra information (overhead or bookkeeping information) is used in order to extract payload and recover the block to its original state. A method to eliminate the need for this extra information is also introduced. This method uses maximum gap that exists between histogram bins for finding the value of pixels that was used for embedding in sender side. Experimental results show that the proposed method provides higher embedding capacity than the original reversible data hiding based on histogram shifting method and its improved versions in the current literature while it maintains the quality of marked image at an acceptable level.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권8호
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• pp.2984-3004
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• 2015

Designing a new reversible data hiding technique with a high embedding rate and a low compression rate for vector quantization (VQ) compressed images is encouraged. This paper proposes a novel lossless data hiding scheme for VQ-compressed images based on the joint neighboring coding technique. The proposed method uses the difference values between a current VQ index and its left and upper neighboring VQ indexes to embed n secret bits into one VQ index, where n = 1, 2, 3, or 4. The experimental results show that the proposed scheme achieves the embedding rates of 1, 2, 3, and 4 bits per index (bpi) with the corresponding average compression rates of 0.420, 0.483, 0.545, and 0.608 bit per pixel (bpp) for a 256 sized codebook. These results confirm that our scheme performs better than other selected reversible data hiding schemes.

• 한국멀티미디어학회논문지
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• 제15권4호
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• pp.526-539
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• 2012

현재까지 연구된 대부분의 정보은닉 기법관련 알고리듬들은 커버영상(cover image)의 변경 또는 조작을 통해 비밀데이터를 삽입(embedding)하여 스테고영상(stego image)을 생성하고, 생성된 스테고영상으로부터 비밀데이터를 추출(extraction)하였다. 이러한 알고리듬은 PSNR의 수치가 높고, 비밀데이터의 수용량(capacity)이 많을수록 좋은 것으로 간주한다. 본 논문에서는 비밀데이터의 패턴(pattern)을 분석하여 숨기는 비밀데이터의 양이 많고, PSNR의 값이 우수한 효율적인 정보은닉 알고리듬을 제안한다. 제안하는 정보은닉 알고리듬은 비밀데이터를 분석하여 비밀데이터 내의 빈도수가 높은 값들을 찾고, 이들의 좌표 값과 인덱스(index)정보를 이용해 커버영상에 삽입한다. 이를 통해 커버영상과 스테고영상 간의 차이는 줄이면서 기존의 제안되었던 알고리듬에 비해 높은 수용량을 보여줌을 실험을 통해 비교한다. 실험결과에서는 5 종류의 비밀 데이터와 8 가지 이하의 패턴을 이용해 커버영상에 삽입하여 생성된 스테고영상과의 차이를 측정한 PSNR과 숨겨진 비밀데이터의 양의 결과를 통해 기존에 제안되었던 알고리듬들 비해 제안하는 정보은닉 알고리듬이 우수함을 보여준다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권1호
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• pp.269-281
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• 2014

Compared to hiding information into digital image, hiding information into digital text file requires less storage space and smaller bandwidth for data transmission, and it has obvious universality and extensiveness. However, text files have low redundancy, so it is more difficult to hide information in text files. To overcome this difficulty, Wang et al. proposed a reversible information hiding scheme using left-right and up-down representations of Chinese characters, but, when the scheme is implemented, it does not provide good visual steganographic effectiveness, and the embedding and extracting processes are too complicated to be done with reasonable effort and cost. We observed that a lot of traditional and simplified Chinese characters look somewhat the same (also called lookalike), so we utilize this feature to propose a novel information hiding scheme for hiding secret data in lookalike Chinese characters. Comparing to Wang et al.'s scheme, the proposed scheme simplifies the embedding and extracting procedures significantly and improves the effectiveness of visual steganographic images. The experimental results demonstrated the advantages of our proposed scheme.

• 한국컴퓨터정보학회논문지
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• 제23권8호
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• pp.85-93
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• 2018

In this research, it is proposed that a method to hide data by modifying directory index entry information. It consists of two methods: a directory list hiding and a file contents hiding. The directory list hiding method is to avoid the list of files from appearing in the file explorer window or the command prompt window. By modifying the file names of several index entries to make them duplicated, if the duplicated files are deleted, then the only the original file is deleted, but the modified files are retained in the MFT entry intact. So, the fact that these files are hidden is not exposed. The file contents hiding is to allocate data to be hidden on an empty index record page that is not used. If many files are made in the directory, several 4KB index records are allocated. NTFS leaves the empty index records unchanged after deleting the files. By modifying the run-list of the index record with the cluster number of the file-to-hide, the contents of the file-to-hide are hidden in the index record. By applying the proposed method to the case of hiding two files, the file lists are not exposed in the file explorer and the command prompt window, and the contents of the file-to-hide are hidden in the empty index record. It is proved that the proposed method has effectiveness and validity.

• 전자공학회논문지CI
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• 제49권2호
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• pp.103-114
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• 2012

공간 도메인에서 많은 DE 기반의 가역정보은닉 기법과 히스토그램 쉬프팅 기반의 가역정보은닉 기법들이 제안되어 왔다. 히스토그램 쉬프팅 기반의 가역정보은닉 기법은 스테고 이미지의 왜곡이 적다는 장점을 갖는다. 하지만 비밀 데이터의 삽입용량이 적고, 추가 데이터가 많다는 단점이 있다. 이에 반해, DE 기반의 가역정보은닉 기법은 높은 삽입 용량을 갖는다는 장점이 있지만 스테고 이미지의 왜곡이 많다는 단점이 있다. 본 논문에서는 삽입 용량을 유지하지만 스테고 이미지의 왜곡을 줄이는 DE 기반의 가역정보은닉 기법을 제안한다. 본 논문에서는 비밀 데이터를 삽입하기 전에 예측 오차들을 블록으로 나눈 후, 각 블록에 비밀 데이터를 삽입할 수 있는지 확인한다. 만약 블록에한 비트의 비밀 데이터만이라도 삽입하면 블록의 픽셀들은 변화한다. 제안하는 기법은 PSNR이 50dB 이상으로 다른 DE 기반의 가역정보은닉 기법보다 스테고 이미지의 왜곡을 줄인다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권2호
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• pp.1020-1042
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• 2019

Reversible data hiding in encrypted images (RDHEI) provides some real-time cloud applications; i.e. the cloud, acting as a data-hider, automatically embeds timestamp in the encrypted image uploaded by a content owner. Many existing methods of RDHEI only satisfy user privacy in which the data-hider does not know the original image, but leaks owner privacy in which the receiver can obtains the original image by decryption and extraction. In the literature, the method of Zhang et al. is the one providing weak content-owner privacy in which the content-owner and data-hider have to share a data-hiding key. In this paper, we take care of the stronger notion, called strong content-owner privacy, and achieve it by presenting a new reversible data hiding in encrypted images. In the proposed method, image decryption and message extraction are separately controlled by different types of keys, and thus such functionalities are decoupled to solve the privacy problem. At the technique level, the original image is segmented along a Hilbert filling curve. To keep image privacy, segments are transformed into an encrypted image by using random permutation. The encrypted image does not reveal significant information about the original one. Data embedment can be realized by using pixel histogram-style hiding, since this property, can be preserved before or after encryption. The proposed method is a modular method to compile some specific reversible data hiding to those in encrypted image with content owner privacy. Finally, our experimental results show that the image quality is 50.85dB when the averaged payload is 0.12bpp.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2007년도 하계종합학술대회 논문집
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• pp.319-320
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• 2007

This paper propose a data hiding for a digital hologram which is the most valuable content. We propose a DCT-domain data hiding method. The data hiding method is composed on the basis of the energy distribution. The method in this paper is the basic guideline. We expected the scheme in this paper are further examined to fine more advanced and efficient data hiding scheme in the near future.