• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1118-1121
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• 2010

With the advent of cell phone digital cameras, and sophisticated photo editing software, digital images can be easily manipulated and altered. Although good forgeries may leave no visual clues of having been tampered with, they may, nevertheless, alter the underlying statistics of an image. Most digital camera equipped in cell phones employ a single image sensor in conjunction with a color filter array (CFA), and then interpolates the missing color samples to obtain a three channel color image. This interpolation introduces specific correlations which are likely to be destroyed when tampering with an image. We quantify the specific correlations introduced by CFA interpolation, and describe how these correlations, or lack thereof, can be automatically detected in any portion of an image. We show the efficacy of this approach in revealing traces of digital tampering in lossless and lossy compressed color images interpolated with several different CFA algorithms in test cell phones.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.309-312
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• 2021

최근 사회는 디지털기술을 기반으로 비대면전환이 빠르게 이루어지고 있다. 이에 디지털 신분증과 디지털 신원인증에 대한 관심이 증가하고 있다. 기존 오프라인에서 사용되고 있는 플라스틱 신분증은 분실 및 위·변조의 위험성이 존재한. 또한 현재 온라인에서 널리 사용되고 잇는 신원인증 모델들을 데이터의 주권이 사용자가 아닌 서비스 제공자에게 있다는 문제점이 있다. 위와 같은 문제들을 해결하고 사용자의 신원정보를 효과적으로 관리하기 위해 분산신원증명의 필요성이 제기되었다. 본 논문에서는 분산신원증명의 구조와 서비스 적용 사례에 대해 살펴본다.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.246-247
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• 2023

최근 문화 공연 수요의 증가에 따라 암표 거래도 증가하는 추세이다. 이를 해결하고자 본 논문은 블록체인 기반 티켓 거래 시스템을 제시한다. 메타마스크로 티켓 거래를 진행하며 블록체인에 거래 내역을 기록함으로써 악의적인 재판매 행위를 근절하는데 목적이 있다. 블록체인 기술을 활용해 티켓 거래 내역의 위변조 위험성을 낮추고 무결성을 보장하여 기존 티켓 거래 사이트보다 높은 신뢰성을 제공한다. 또한 티켓 재판매 시 가격을 원가 이하로 제한하고 양도자의 지갑 주소를 양수자에게 비공개하여 사이트 외 추가적인 불법 거래를 방지한다. 본 연구가 공정한 디지털 거래 환경을 조성할 것이라 기대한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.807-808
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• 2023

공증이란 "공증인에 의한 공적인 증명"의 준말로서, 법무부 지방검찰청 소속의 "공증인"이 특정한 사실 및 법률관계의 존재를 공적으로 증명하는 행위를 말한다. 공증문서 위변조 방지를 위해 NFT 에 거래방지 기능이 추가된 SBT 를 이용하여 블록체인으로 문서를 관리해 무결성과 진본성을 보장하는 스마트 공증 플랫폼을 제안한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.4
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• pp.635-643
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• 2014

Most of the web-based services are provided by a web browser. A web browser receives a text-based web page from the server and translates the received data for the user to view. There are a myriad of add-ons to web browsers that extend browser features. The browser's add-ons may access web pages and make changes to the data. This makes web-services via web browsers are vulnerable to security threats. A web browser stores web page data in memory in the DOM structure. One method that prevents modifications to web page data applies hash values to certain parts in the DOM structure. However, a certain characteristic of web-pages renders this method ineffective at times. Specifically, the user-input data is not pre-determined, and the hash value cannot be calculated prior to user input. Thus the modification to the data cannot be prevented. This paper proposes a method that both detects and inhibits any attempt to change to user-input data. The proposed method stores user-input from the keyboard and makes a comparison with the data transmitted from the web browser to detect any anomalies.

• The KIPS Transactions:PartB
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• v.18B no.6
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• pp.355-364
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• 2011

In most applications requiring high-confidential images, reversible watermarking is an effective way to ensure the integrity of images. Many watermarking researches which have been adapted to authenticate contents cannot recover the original image after authentication. However, reversible watermarking inserts the watermark signal into digital contents in such a way that the original contents can be restored without any quality loss while preserving visual quality. To detect malicious tampering, this paper presents a new block-based image authentication algorithm using differential histogram-based reversible watermarking. To generate an authentication code, the DCT-based authentication feature from each image block is extracted and combined with user-specific code. Then, the authentication code is embedded into image itself with reversible watermarking. The image can be authenticated by comparing the extracted code and the newly generated code and restored into the original image. Through experiments using multiple images, we prove that the presented algorithm has achieved over 97% authentication rate with high visual quality and complete reversibility.

• Journal of Digital Convergence
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• v.10 no.2
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• pp.153-159
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• 2012

Now a days, U-healthcare comes into the spotlight as a new business model which combines RFID technology with medical service in the well-being era and IT popularization. U-healthcare service needs a method that can deals with hand-writing, overlap data, forgery and falsification of data, difference between information version that happen in medical process because of graft between RFID technology and u-healthcare. This paper proposes RFID based user certification protocol to protect user's privacy who gets medical service through U-healthcare. In the protocol, secret information of patient does the XOR with the secret key that is created in the hospital to reconsider the stability of security system of U-healthcare and user's data forgery and falsification and privacy and then saves it in the secret key field of patient in DB table. Also, it informs the case of illegal access to certification server and make it approved the access of u-healthcare service by differentiating whether u-healthcare is illegal or not.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.88-95
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• 2012

The passport is not only an officially proven document in order to identify the nationalities of travelers, but also request for protections of travelers. Since the overseas trips have been increased, the uses of forged or modulated passports are also now rapidly increasing. The forged or modulated passports are mainly used by international criminal organization or offenders, who are restricted by immigration control, in order to avoid under the radar and conceal their identities. The purpose of biometric authentication technology is to define one's unique identities through the comparative analysis one's unique finger prints, iris, sweat gland, blood vessel, palm pattern, vein distribution, voice, and etc. We have been studying about applicable and possibilities of the biometric authentication technology for overseas travel without passports. In hence, we have been also collected various of technical references of using biometric authentication, and have been analyzed what is the best biometric to be alternatively used instead of passports.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.3
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• pp.895-905
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• 2018

Public opinion polls have a strong influence on modern society as a means of examining the tendency of social groups on specific issues. As the influence of the polls increases, the problem of forgery and falsification of the results becomes an important issue. So, to guarantee the reliability of the results, our society needs novel mechanisms. As one of such mechanisms, the Ethereum blockchain is an environment for developing decentralized applications with the reliable blockchain technology. Ethereum decentralized applications can utilize smart contracts to provide services for users in transparent and reliable ways. In this paper, we propose a polling method that guarantees reliability using the blockchain technology, which is a distributed ledger technique that makes forgery or falsification actually impossible. The proposed method provides a robust verification function on the results of the associated polls for individual voters and verification organizations. Also, we present a distributed opinion polling application running on our private Ethereum blockchain network, showing the effectiveness of the proposed method.

• Journal of Food Hygiene and Safety
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• v.35 no.6
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• pp.574-580
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• 2020

In this study we sought to determine the food fraud by discriminating species of commercial seafood product such as Larimichthys polyactis, Larimichthys crocea, Pennahia argentatus, and Miichthys miiuy, which are difficult to morphologically discriminate. After amplifying the mitochondrial cytochrome c oxidase subunit I gene of the reference fish, the DNA sequences of the amplified PCR products were analyzed. As a result, a 655 bp sequence for species identification was selected for use as DNA barcodes. To confirm the DNA data and primer set, the DNA barcode sequence of each fish was compared to that in that in the NCBI. All of the DNA barcode data were matched with the gene sequence of each fish in the NCBI. A total of 32 processed seafood products (8 L. polyactis, 12 L. crocea, 3 Pennahia argentatus, and 9 Miichthys miiuy) were investigated. Homology of 97% or more in DNA sequences was judged as the same species. As a result of the monitoring, there were no discovered cases of forgery or alteration. However, the use of a raw material name having no matching standard name in the Korea Food Code may cause consumer confusion. Therefore, it is suggested that the standard name or scientific name be co-labeled with the raw material name on seafood products to prevent consumer confusion.