• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.3
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• pp.177-183
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• 2020

Steganography uses digital images as a medium for sending secret messages over insecure networks. There is also a least significant bit(LSB) that is a popular method of embedding secret messages in digital images. The goal of steganography is to securely and flawlessly transmit secret messages using stego media over a communication channel. There is a need for a method to improve resistance to reduce the risk of exposure to third parties. To safely hide secret messages, I propose new algorithms that go through crossing, encryption, chaos and concealment steps. After separating Hangul syllables into choseong, jungseong and jongseong, the bitwised message information is encrypted. After applying the logistic map, bitwised information is reconstructed using the position of the chaotic sequence. The secret message is inserted into the randomly selected RGB channel. PSNR and SSIM were used to confirm the effectiveness of the applied results. It was confirmed as 44.392(dB) and 0.9884, respectively.

• Convergence Security Journal
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• v.10 no.2
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• pp.19-26
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• 2010

In this study, we try to make up for the vulnerability in steganography that it is easily revealed the hidden logo image in cover image by bit-plane extraction. For this, we apply some methods, the permutation which shift the scattered pieces of logo image to one side, bit-plane dispersion insertion method and pack-type compressor.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.3
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• pp.22-30
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• 2008

Recently, protection of personal information is getting more important. Many countries have legislated about the protection of personal information. Now, the protection of relevant personal information is required not for a simple image of enterprises but law obligation. Most databases in enterprises used to store customers' names, addresses and credit card numbers with no exceptions. The personal information about a person is sensitive, and this asset is strategic. Therefore, most enterprises make an effort to preserve personal information safely. If someone, however, hacks password information of DBMS manager, no one can trust this system. Therefore, encryption is required based in order to protect data in the database. Because of database encryption, however, it is the problem of database performance in terms of computation time and the limited SQL query. Thus, we proposed an efficient query method to solve the problem of encrypted data in this paper.

• Journal of Internet of Things and Convergence
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• v.8 no.2
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• pp.79-84
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• 2022

This paper presents an enhancement method of document restoration capability which is robust for security, loss, and contamination, It is based on two methods, that is, encryption and DnCNN(DeNoise Convolution Neural Network). In order to implement this encryption method, a mathematical model is applied as a spatial frequency transfer function used in optics of 2D image information. Then a method is proposed with optical interference patterns as encryption using spatial frequency transfer functions and using mathematical variables of spatial frequency transfer functions as ciphers. In addition, by applying the DnCNN method which is bsed on deep learning technique, the restoration capability is enhanced by removing noise. With an experimental evaluation, with 65% information loss, by applying Pre-Training DnCNN Deep Learning, the peak signal-to-noise ratio (PSNR) shows 11% or more superior in compared to that of the spatial frequency transfer function only. In addition, it is confirmed that the characteristic of CC(Correlation Coefficient) is enhanced by 16% or more.

• Journal of the Korea Society of Computer and Information
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• v.25 no.1
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• pp.71-77
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• 2020

In this paper, we propose a method in which PingPong256 combines LFSR and variable clock to generate an irregular PRNG and use it for image encryption. PingPong256 is guaranteed an extended period based on the two LFSRs, and the variable clock is a structure that outputs the result of operating a predetermined clock in one operation by referring to the state of the different LFSR. A variable clock is characterized by the difficulty of predicting the output at any time because the choice increases with time. PingPong256 combines the advantages of LFSR and variable clock, the convenience of hardware and software implementation, and the benefits of sensitivity and irregular periods. Also, the statistical safety was verified using the NIST SP800-22, the safety of the proposed method, and the sensitivity of the image change was tested using NPCR and UACI.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.3
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• pp.277-282
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• 2018

The goal of the secret message communication on the internet is to maintain invisibility and confidentiality. Digital steganography is a technique in which a secret message is inserted in a cover medium and transmitted to a destination so that a third party can not perceive the existence of the message itself. Steganography is an efficient method for ensuring confidentiality and integrity together with encryption techniques. In order to insert a secret (Hangul) message, I propose a image steganography method that the secret character is separated and converted into binary code with reference to the encryption table, the cover image is divided into two areas, and the secret message and the right l-LSB information of the second area are encrypted and crossed, concealing the k-LSB of the first region. The experimental results of the proposed method show that the PSNR value is 52.62 and the acceptable image quality level.

• The KIPS Transactions:PartB
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• v.8B no.5
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• pp.579-586
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• 2001

Digital watermarking is to embed imperceptible mark into image, video, audio, and text data to prevent the illegal copy of multimedia data. arbitrary modification, and also illegal sales of the copies without agreement of copyright ownership. In this paper, we study for the embedding and extraction of watermark key using wavelet in the luminance signal in order to implement the system to protect the copyright for image MPEG. First, the original image is analyzed into frequency domain by discrete wavelet transform. The RSA(Rivest, Shamir, Aldeman) public key of the coded target is RUN parameter of VLD(variable length coding). Because the high relationship among the adjacent RUN parameters effect the whole image, it prevents non-authorizer not to possess private key from behaving illegally. The Results show that the proposed method provides better moving picture and the distortion more key of insert than direct coded method on low-frequency domain based DCT.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.325-327
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• 2004

무선 인터넷의 보급과 맞물려 모바일 컴퓨팅 환경이 구축됨에 따라 PDA와 같은 소형의 모바일 장비에 최적화된 디지털 컨텐츠의 제작 및 배포가 활발해지고 있으며 불법적인 디지털 컨텐츠의 이용 또한 이에 비례하고 있다. 그러나 유선환경에 기반 한 기존의 DRM 시스템은 상대적으로 속도와 표현능력이 떨어지는 모바일 환경에는 적합하지 않으며 현재 연구.개발된 모바일 환경에서의 DRM 시스템은 음악, 문서, 이미지에 국한되어 있어 동영상과 암호화와 같은 높은 연산 능력을 요구하는 부분의 개발과 연구는 초기 단계에 머물러 있다. 본 논문에서는 모바일 환경에 적합하도록 적은 연산 능력으로도 기존의 DRM 시스템에 준하는 보안 강도를 갖을 수 있도록 동영상의 부분 암호화 방식과 공유키 풀 기반의 인증 방법을 사용하는 DRM 시스템을 설계ㆍ제안한다.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.6 no.6
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• pp.103-110
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• 2016

The recent frequent cases of damage due to leakage of medical data and the privacy of medical patients is increasing day by day. The government says the Privacy Rule regulations established for these victims, such as prevention. Medical data guidelines can be seen 'national medical privacy guidelines' is only released. When replacing the image data between the institutions it has been included in the image file (JPG, JPEG, TIFF) there is exchange of data in common formats such as being made when the file is leaked to an external file there is a risk that the exposure key identification information of the patient. This medial image file has no protection such as encryption, This this paper, introduces a masking technique using a mosaic technique encrypting the image file contains the application to optical character recognition techniques. We propose pseudonymization technique of personal information in the image data.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10a
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• pp.796-798
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• 2001

본 논문에서는 벡터 양자화(Vector Quantization)를 이용해서 소유자의 저작물에 대해 저작권을 보호할 수 있는 디지털 워터마킹(Watermarking) 기법을 제안한다. 소유자의 워터마크 정보로는 사용자 정보를 비밀키를 이용해서 암호화한 데이터를 사용하며, 워터마킹 처리는 원본 이미지를 웨이블렛 기반의 벡터 양자화(Vector Quantization)에 사용되는 코드북(Coodbook)을 이용한다. 코드북을 사용함으로서 양질의 정보를 유지하면서 워터마킹을 효과적으로 처리할 수 있다.