• KNOM Review
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• v.22 no.1
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• pp.68-76
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• 2019

Bitcoin, based on the blockchain technology is an online crypto-currency developed by Satoshi Nagamoto. Bitcoin, which was first issued on January 3, 2009, is rapidly evolving with increasing number of transactions. However, untoward incidents are occurring due to an increase in the number of Bitcoin transactions. Predicting the number of Bitcoin transactions is important to prepare for any issues that can occur in the Bitcoin network. This paper proposes to design model for predicting the number of Bitcoin transactions by applying two machine learning algorithms and then a model for predicting the number of Bitcoin transactions through experiments.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.341-343
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• 2021

현재 웹툰 시장이 크게 성장하고 있는 가운데, 과도한 매출 수수료 및 불공정 계약 등 부조리한 수익분배 문제가 불거지고 있다. 본 논문은 웹툰 플랫폼의 수익모델을 보완하는 NFT 기반 웹툰거래 및 수익분배 시스템을 소개하고자 한다. NFT 는 고유한 값을 가진 토큰으로, 디지털 자산에 대한 소유권 인증에 용이하며 블록체인 네트워크 상에서 구매 이력 등의 데이터 위변조가 어렵다는 특징이 있다. 또한 암호화폐처럼 손쉽게 거래할 수 있고 재판매가 가능하다는 장점 때문에 예술 분야에서 각광받고 있다. 이에 웹툰에 NFT 를 발행하여 웹툰을 소장 및 거래하고, NFT 소장 비율에 따라 해당 웹툰의 열람 수익을 나눠 가질 수 있는 시스템을 개발하여 제안한다.

• Journal of Industrial Convergence
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• v.18 no.4
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• pp.87-92
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• 2020

Recently, several sporting events have been canceled or postponed due to the influence of COVID-19's imposed social distancing in life, or are being played without spectators. As a result, the market for sports products has been stagnant, and many are experiencing difficulties. To get over it, sports market players are exploring various new markets such as online fan services and online sales. Therefore, this study proposed a way to manage the authenticity of sports-related products. The block structure, system flow, and network model were designed and prototypes were developed accordingly. Experts were invited through the derived method to conduct a target group interview (FGI) to evaluate the reliability and stability of the transaction process, the reliability and stability of payment, the tracking of accidents, and the reliability and stability of the system. Through this study, consumers can have reliability when trading sports-related products such as goods, favorite items, and sign balls.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.5
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• pp.165-170
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• 2023

With the recent rise of blockchain technology, cryptocurrency platforms using it are increasing, and currency transactions are being actively conducted. However, crimes that abuse the characteristics of cryptocurrency are also increasing, which is a problem. In particular, phishing scams account for more than a majority of Ethereum cybercrime and are considered a major security threat. Therefore, effective phishing scams detection methods are urgently needed. However, it is difficult to provide sufficient data for supervised learning due to the problem of data imbalance caused by the lack of phishing addresses labeled in the Ethereum participating account address. To address this, this paper proposes a phishing scams detection method that uses both Trans2vec, an effective graph embedding techique considering Ethereum transaction networks, and semi-supervised learning model Tri-training to make the most of not only labeled data but also unlabeled data.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.5
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• pp.889-899
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• 2021

This paper proposes a reliable data sharing scheme on the internet of vehicles (IoV) by utilizing blockchain technology for constructing a decentralized system approach. In our model, to maintain the credibility of the information messages sent by the vehicles to the system, we propose a reputation rating mechanism, in which neighboring vehicles validate every received information message. Furthermore, we incorporate an incentive mechanism based on smart contracts, so that vehicles will get certain rewards from the system when they share correct traffic information messages. We simulated the IoV network using a discrete event simulator to analyze network performance, whereas the incentive model is designed by leveraging the smart contract available in the Ethereum platform.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.330-333
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• 2021

2020년 전자서명법 개정으로 공인인증서가 폐지됨에 따라 자체 인증 기술의 도입이 필요한 실정이다. 특히나 COVID-19로 인한 비대면 상황이 지속됨에 따라 기존 아날로그 방식을 통해 대면으로 계약서를 작성하고 수립하는데 많은 비효율적 문제가 대두되었다. 디지털 전환 가속화와 비대면 거래확대로 인한 전자 신원확인 중요성이 점차 커지고 있음에 따라 전자 서명 및 전자 봉투 방식으로 계약할 수 있는 안전한 시스템 개발을 진행하고자 한다. 이를 위해 계약 시스템의 보안 요구 사항을 도출하였으며 최종적으로 NFT 연동을 통해 안전한 계약을 진행할 수 있도록 프로세스를 설계하였다. 시스템의 동작 방식을 표현하기 위하여 DFD 등을 포함한 Diagram 형태로 나타내었으며 실제 프로토타입을 제작 후 블록체인 네트워크에 연결한 뒤 테스트를 진행하여 시스템 검증을 수행하였다. 추후 이 시스템을 통해 B2B, B2C 모델 등의 모델 기반 다양한 거래와 계약이 가능하도록 구성할 예정이며 추가적인 연구를 진행하여 사용자 측면에서 더 간편하고 안전한 환경이 될 수 있도록 고도화 시키는 것을 목표로 한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.4
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• pp.1009-1019
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• 2018

Bitcoin is the first application utilizing the blockchain, but it has limitations in terms of scalability. The concept of Lightning Network was recently introduced to address the scalability problem of Bitcoin. In this paper, we found that the real-world Bitcoin Lightning Network shows the scale-free property. Therefore, the Bitcoin Lightning Network can be vulnerable to the intentional attacks targeting some specific nodes in the network while it is still robust to the random node failures. We experimentally analyze the robustness of the Bitcoin's Lightning Network via the simulation of network attack model. Our simulation results demonstrate that the real-world Lightning Network is vulnerable to target attacks that destroy a few nodes with high degree.

• Journal of Platform Technology
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• v.8 no.3
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• pp.3-9
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• 2020

As the need for sharing for research purposes in the medical field increases, the use of a Common Data Model (CDM) is increasing. However, when sharing CDM data, there are some problems in that access control and personal information in the data are not protected. In this paper, in order to solve this problem, access to CDM data is controlled by using an encryption method in a blockchain network, and information of CDM data is recorded to enable tracking. In addition, IPFS was used to share a large amount of CDM data, and Celery was used to automate the sharing process. In other words, we propose a multi-channel automation system in which the information required for CDM data sharing is shared by a trust-based technology, a distributed file system, and a message queue for automation. This aims to solve the problem of access control and personal information protection in the data that occur in the process of sharing CDM data.