• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.2
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• pp.94-101
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• 2012

This paper proposes an improved image steganalysis scheme to raise the detection rate of stego images out of cover images. To improve the detection rate of stego image in the steganalysis, tiny variation caused by data hiding should be amplified. For this, we extract feature vectors of cover image and stego image by two steps. First, we separate image into upper 4 bit subimage and lower 4 bit subimage. As a result, stego noise is expanded more than two times. We decompose separated subimages into twelve subbands by applying 3-level Haar wavelet transform and calculate co-occurrence probabilities of two different subbands in the same scale. Since co-occurrence probability of the two wavelet subbands is affected by data hiding, it can be used as a feature to differentiate cover images and stego images. The extracted feature vectors are used as the input to the multilayer perceptron(MLP) classifier to distinguish between cover and stego images. We test the performance of the proposed scheme over various embedding rates by the LSB, S-tool, COX's SS, and F5 embedding method. The proposed scheme outperforms the previous schemes in detection rate to existence of hidden message as well as exactness of discrimination.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.8
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• pp.1926-1945
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• 2012

In this paper, two practical forensics aided steganalyzers (FA-steganalyzer) for heterogeneous bitmap images are constructed, which can properly handle steganalysis problems for mixed image sources consisting of raw uncompressed images and JPEG decompressed images with different quality factors. The first FA-steganalyzer consists of a JPEG decompressed image identifier followed by two corresponding steganalyzers, one of which is used to deal with uncompressed images and the other is used for mixed JPEG decompressed images with different quality factors. In the second FA-steganalyzer scheme, we further estimate the quality factors for JPEG decompressed images, and then steganalyzers trained on the corresponding quality factors are used. Extensive experimental results show that the proposed two FA-steganalyzers outperform the existing steganalyzer that is trained on a mixed dataset. Additionally, in our proposed FA-steganalyzer scheme, we can select the steganalysis methods specially designed for raw uncompressed images and JPEG decompressed images respectively, which can achieve much more reliable detection accuracy than adopting the identical steganalysis method regardless of the type of cover source.

• Journal of Broadcast Engineering
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• v.6 no.1
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• pp.13-20
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• 2001

In this paper, we propose a new digital audio watermarking scheme In the cepstrum domain. We insert a digital watermark signal Into the cepstral components of the audio signal using a technique analogous to spread spectrum Communications, hiding a narrow band signal in a wade band channel. In our proposed method, we use pseudo-random sequences to watermark the audio signal. The watermark Is then weighted in the cepstrum domain according to the distribution of cepstral coefficients and the frequency masking characteristics of the human auditory system. The proposed watermark embedding scheme minimizes audibility of the watermark signal. and the embedded watermark is robust to mu1tip1e watermarks, MPEG audio ceding and additive noose.

• The Journal of the Korea Contents Association
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• v.13 no.6
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• pp.20-29
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• 2013

The compression of video data is intended for real-time transmission of band-limited channels. Compressed video bit-streams are very sensitive to transmission error. If we lose packets or receive them with errors during transmission, not only the current frame will be corrupted, but also the error will propagate to succeeding frames due to the spatio-temporal predictive coding structure of sequences. Error detection and concealment is a good approach to reduce the bad influence on the reconstructed visual quality. To increase concealment efficiency, we need to get some more accurate error detection algorithm. In this paper, We hide specific data into the motion vector difference of each macro-block, which is obtained from the procedure of inter prediction mode in H.264/AVC. Then, the location of errors can be detected easily by checking transmitted specific data in decoder. We verified that the proposed algorithm generates good performances in PSNR and subjective visual quality through the computer simulation by H.324M mobile simulation tool.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.3
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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.

• Journal of Digital Contents Society
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• v.16 no.4
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• pp.535-543
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• 2015

Recently, NAND flash based storage devices are being used as a storage device in various fields through hiding the limitations of NAND flash memory and maximizing the advantages. In particular, those storage devices contain a software layer called Flash Translation Layer(FTL) to hide the "erase-before-write" characteristics of NAND flash memory. FTL includes the metadata for managing the data requested from host. That metadata is stored in internal memory because metadata is very frequently accessed data for processing the requests from host. Thus, if the power-loss occurs, all data in memory is lost. So metadata management scheme is necessary to store the metadata periodically and to load the metadata in the initialization step. Therefore we proposed the scheme which satisfies the core requirements for metadata management and efficient operation. And we verified the efficiency of proposed scheme by experiments.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.6
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• pp.86-92
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• 2010

This paper proposes a new steganography scheme based on frequency domain using various image frames and collages that can protect the copyright of digital contents for users and securely perform to exchange the security information in the digital communication environments. The main idea of our proposed scheme is that the security informations related its copyright embed into the frequency domain of the image frame and collages when a user decorates the original image by using various image frames and collages. The strengths of our proposed scheme are as follows: (1) It allows to freely control the quantity of embedded information by changing the number of image frames and collages. (2) It is secure to variety image distortion attacks. (3) It maintains high PSNR(Peak Signal to Noise Ratio). As a result, the proposed steganography scheme can be used practically diverse multimedia security fields such as digital copyright protect, secure message communication and digital watermarking.

• Journal of information and communication convergence engineering
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• v.12 no.4
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• pp.237-245
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• 2014

In this study, software-based countermeasures against a side-channel cryptanalysis of the Rabbit stream cipher were developed using Moteiv's Tmote Sky, a popular wireless sensor mote based on the Berkeley TelosB, as the target platform. The countermeasures build upon previous work by improving mask generation, masking and hiding other components of the algorithm, and introducing a key refreshment scheme. Our contribution brings improvements to previous countermeasures making the implementation resistant to higher-order attacks. Four functional metrics, namely resiliency, robustness, resistance, and scalability, were used for the assessment. Finally, performance costs were measured using memory usage and execution time. In this work, it was demonstrated that although attacks can be feasibly carried out on unprotected systems, the proposed countermeasures can also be feasibly developed and deployed on resource-constrained devices, such as wireless sensors.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.278-280
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• 2011

본 논문은 이미지가 갖는 R, G, B 비율의 분산을 이용하여, 공간 영역에서 정보를 은닉하는 알고리즘을 제시한다. 웹 상에서 Jpeg, bmp, gif 등의 포멧을 갖는 이미지를 raw 파일로 변환한 후, R,G,B 비율을 구한다. 그 중 사람의 눈에 가장 둔감한 B 비율 분산을 조작하여 정보를 은닉하는데 이용한다. 또한 오류율을 낮추기 위하여 (15,7)BCH Code 를 사용한다. 제안된 알고리즘이 JPEG(Joint Photographic coding Experts Group) compression, scale(이미지의 크기 변화), Mediancut 과 같은 이미지 변화에 강한 특성과 정보은닉 후에도 화질열화가 발생하지 않는 특성을 실험을 통해 보인다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1303-1306
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• 2005

무선 센서 네트워크는 저가의 많은 노드들로 구성되어 있으며. 이 노드들은 정보수집, 계산, 통신을 위한 전력등을 가지고 있다. 센서 네크워크에서의 보안을 위하여 주로 암호화 방법이 사용되고 있으나 자원이 제약적인 센서 네크워크에서 많은 에너지와 계산을 필요로 하는 암호화 방법은 센서 노드의 수명을 단축시킨다. 이를 보완하기 위하여 본 논문에서는 위치정보 은닉을 이용한 저전력 보안방법을 제안한다. 제안된 방법에서는 위치정보의 은닉을 위하여 상대거리정보를 사용하며, 센서 노드간 통신에서는 상대좌표로부터 구할 수 있는 노드사이의 상대거리정보가 사용된다.