• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.1803-1806
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• 2003

This paper presents a H/W module that executes a fragile watermarking algorithm. The module inputs sequentially quantized DCT values, encodes watermark and then outputs watermarked DCT coefficients. A fragile and invisible watermarking algorithm is adopted, modified and enhanced here to reduce H/W size and image degradation. The module can be directly inserted between DCT quantizer and VLC encoder in wide spread JPEG/MPEG encoder. The module is expected to be used for real-time authentication purpose in DVR(Digital Video Recorder) or digital cameras.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.562-564
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• 2000

지문은 사람에 있어서 유일한 특징과 변하지 않는 특성으로 인하여 개인의 인증이나 식별에 많이 사용되고 있다. 이러한 특성을 가진 지문을 스마트 카드의 인증과정에 이용함으로서 보안성을 높이고 사용에 편리함을 추가할 수 있다. 본 논문에서는 지문의 특징점 추출 과정과 매칭 방법 그리고 자바카드에 지문을 등록하는 프로토콜과 인증하는 프로토콜을 제시하고 구현하였다.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.105-108
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• 2002

This paper proposes a new watermarking algorithm to embed data in 1-bit images using edges for protecting illegal copies or modifications. This method is based on edge detection to decide the most invisible region. This paper also introduces a new shuffling method which embeds data in each blocks uniformly and finds Positions under the limited attacks. In experiment, we compare the proposed shuffling method with M. Wu's method.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11c
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• pp.1851-1854
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• 2003

본 논문에서는 영상의 인증과 무결성을 위한 새로운 블록 연성 워터마킹을 제안한다. 원 영상의 인증과 무결성을 확인하기 위하여 이진로고 영상을 워터마크로 사용한다. 원 영상의 각 픽셀의 정보뿐만 아니라 해당 블록의 정보로 binary look-up table을 선택하여 워터마크 비츠를 삽입한다. 기존 방식의 문제점으로 제시된 공격[6,7]을 효율적으로 막으면서도 시각적으로 변조유무 및 픽셀단위 또는 블록단위로 변조위치를 감지할 수 있음을 보인다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.646-648
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• 2003

본 연구는 이미지 합성을 이용하여 서버가 사용자를 인증하기 위한 알고리즘을 개발하고 이들을 구현하여 그 성능을 평가하고 분석한다. 서버는 사용자가 소지하는 사용자카드를 랜덤하게 점을 찍어 생성하고, 각 사용자에게 배포된 사용자카드의 정보를 유지.관리한다. 한 사용자로부터 인증요청이 들어오면, 서버는 그 사용자의 사용자카드 정보를 기반으로 서버카드를 실시간에 생성하여 사용자에게 송신한다. 서버카드는 인증마다 다르게 생성되므로 원타임 패스워드 챌린지(challenge) 역할을 한다. 사용자는 본인이 소유하고 있는 사용자카드와 서버로부터 송신된 서버카드를 겹쳤을 때 생성되는 이미지를 판독하여 인증을 수행한다. 보안성을 높이면서 이미지 판독을 효율적으로 하기 위해 다양한 기법을 제시하고 구현을 통하여 실용성을 진단한다.

• Journal of Broadcast Engineering
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• v.5 no.2
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• pp.290-299
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• 2000

In this paper, we introduce a watermarking technique using a block-based wavelet transform. Our objective is to achieve the invisibility of the watermark embedded into an image. That is, the difference between the original image and the watermarked image is perceptually invisible. Also, we propose a scheme that is robust to common Image processing by embedding the watermark into ail frequencies. Especially, we certified that the proposed watermarking algorithm was robust to JPEG compression and noise. In addition, our detection scheme can detect the manipulated area for the purpose of authentication. From the experimental results, we conclude that the proposed watermarking system satisfied the objectives proposed in this paper.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.4
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• pp.302-306
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• 2001

Because face Images have many variations(expression, illumination, orientation of face, etc), there has been no popular method which has high recognition rate. To solve this difficulty, data fusion that fuses various information has been studied. But previous research for data fusion fused additional biological informationUingerplint, voice, del with face image. In this paper, cooperative results from several face image recognition modules are fused without using additional biological information. To fuse results from individual face image recognition modules, we use re-defined mass function based on Dempster-Shafer s fusion theory.Experimental results from fusing several face recognition modules are presented, to show that proposed fusion model has better performance than single face recognition module without using additional biological information.

• The KIPS Transactions:PartC
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• v.14C no.1 s.111
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• pp.39-44
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• 2007

In this paper, we propose a reversible watermarking method to recover an original image after the watermark has been extracted. Most watermarking algorithms cause degradation of image quality in original digital content in the process of embedding watermark. In the proposed algorithm, the original image can be obtained when the degradation is removed from the watermarked image after extracting watermark information. In the proposed method, we utilize histogram shifting concept and Location Map structure. We could solve the Filp-Flop problem by using Location Map structure and enlarge the information embedding capacity by embedding recursively. Experimental results demonstrate that the embedding information as large as 120k bits can be realized while the invisibility as high as 41dB can be maintained.

• The Journal of Information Technology
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• v.9 no.4
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• pp.49-55
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• 2006

In this paper, a new fragile watermarking algorithm for digital image is presented, which makes resolving the security and forgery problem of the digital image to be possible. The most suitable watermarking method that verifies the authentication and integrity of the digital image is the Wong's method, which invokes the hash function (MD5). The algorithm is safe because this method uses the hash function of the cryptology. The operations such as modulus, complement, shift, bitwise exclusive-or, bitwise inclusive-or are necessary for calculating the value of hash function. But, in this paper, an Arithmetic encoding method that only includes the multiplication operation is adopted. This technique prints out accumulative probability interval, which is obtained by multiplying the input symbol probability interval. In this paper, the initial probability interval is determined according to the value of the key, and the input sequence of the symbols is adjusted according to the key value so that the accumulative probability interval will depend on the key value. The integrity of the algorithm has been verified by experiment. The PSNR is above the 51.13db and the verifying time is $1/3{\sim}1/4$ of the verifying time of using the hash function (MD5), so, it can be used in the real-time system.

• International Journal of Computer Science & Network Security
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• v.21 no.12spc
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• pp.648-656
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• 2021

Color digital images are used in many multimedia applications and in many vital applications. Some of these applications require excellent protection for these images because they are confidential or may contain confidential data. In this paper, a new method of data cryptography is introduced, tested, and implemented. It will be shown how this method will increase the security level and the throughput of the data cryptography process. The proposed method will use a secret image_key to generate necessary private keys for each byte of the data block. The proposed method will be compared with other standard methods of data cryptography to show how it will meet the requirements of excellent cryptography, by achieving the objectives: Confidentiality, Integrity, Non-repudiation, and Authentication.