• The Journal of the Korea Contents Association
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• v.18 no.7
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• pp.620-627
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• 2018

With the widespread adoption of blockchain in the field of business, the importance of confidentiality of critical information has been emerging. Although blockchain models solve the security problem regarding integrity threat by sharing transactions and making them public, it is vulnerable in terms of confidentiality. Therefore, a security mechanism to provide confidentiality of critical information and private information of a firm is necessary to utilize block chain in the process of work. In order to solve the problem, we suggest Private blockchain based cryptographic protocol application model using Smart contract commitment scheme of the Ethereum. It can contribute to activation of blockchain services by enabling non-trusted participants to perform businesses through application of smart contract enhanced in terms of confidentiality and integrity to private blockchain.

• Journal of Internet Computing and Services
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• v.20 no.6
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• pp.105-117
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• 2019

Bitcoin, which can be classified as a cryptocurrency, has attracted attention from various industries because it is an innovative digital currency and the beginning of a Blockchain system. However, as the research on Bitcoin progressed, several security vulnerabilities and possible attacks were analyzed. Among them, the security problem caused by the transparency of the Blockchain database prevents the Blockchain system from being applied to various fields. This vulnerability is further classified as the weak anonymity of participating nodes and privacy problem due to disclosure of transaction details. In recent years, several countermeasures have been developed against these vulnerabilities. In this paper, we first describe the main features of the public and private Blockchain, and explain privacy, unlinkability and anonymity. And, three public Blockchain platforms, Dash, Zcash and Monero which are derived from Bitcoin, and Hyperledger Fabric which is a private Blockchain platform, are examined. And we analyze the operating principles of the protocols applied on each platform. In addition, we classify the applied technologies into anonymity and privacy protection in detail, analyze the advantages and disadvantages, and compare the features and relative performance of the platforms based on the computational speed of the applied cryptographic mechanisms.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.4
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• pp.115-121
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• 2020

As the participation of blockchain increases, governance to maintain the ecosystem is being activated. Governance must be managed/supervised to maintain and improve the blockchain. However, as the usage of blockchain increases, there is a limit for people to manage it individually. In addition, smart contracts applied from Ethereum need to be verified for trade that are determined according to status values, as new trade types are possible. This research proposes a surveillance system, Blockchain Watchdog, based on the state monitoring of the blockchain smart contract as a tool for maintaining and developing the blockchain ecosystem of governance, and implemented and tested the surveillance system. As a case study, we conducted experiments on Ropsten and Ganache, and were able to see real-time information collection and visualization using dashboards, graphs, and charts. We expect to contribute to the maintenance and development of the ecosystem of blockchain governance through Blockchain Watchdog.

• Review of KIISC
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• v.30 no.3
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• pp.31-36
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• 2020

사용자를 온라인에서 확인하는 인증 기술은 최근 코로나 19로 인한 비대면 서비스들의 확산으로 더욱 중요해졌다. 이러한 인증 기술로는 인터넷/모바일 뱅킹, 전자 정부 등에 널리 사용되고 있는 공인인증서부터 카카오 뱅크 등의 사설인증, 블록체인을 이용한 분산ID 기술, 사용자 편의성을 강조한 간편 인증 등으로 진화하고 있다. 본 기고에서는 여러 가지 형태의 인증 방식에 대한 특징과 동향을 살펴보고 이를 통한 발전 방향을 살펴보고자 한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.161-169
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• 2018

This study presents a time synchronization system in decentralized structure by using the blockchain, a core technology of Bitcoin introduced by Satoshi Nakamoto in 2008. In this study, Getting away from existing time synchronization system in centralized structure, A blockchain network has completely decentralized structure using public blockchain. In decentralized structure, Only certain peers among the peers that participate in a blockchain network access the NTP server. Therefore, others can synchronize time without having to go to public network. Furthermore if appropriate time synchronization cycles are established for each peer, time synchronization can be maintained even when connection to public network is completely lost. A time synchronization system in this study has advantages of p2p system and can be also guaranteed reliability and stability because it used digital signature, merkle tree, consensus algorithm which are core characteristics of block chains.

• Journal of Korea Society of Digital Industry and Information Management
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• v.14 no.2
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• pp.11-17
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• 2018

IDS/IPS and networked computer systems are playing an increasingly important role in our society. They have been the targets of a malicious attacks that actually turn into intrusions. That is why computer security has become an important concern for network administrators. Recently, various Detection/Prevention System schemes have been proposed based on various technologies. However, the techniques, which have been applied in many systems is useful for existing intrusion patterns on standard-only systems. Therefore, probe detection of private clouds using BlockChain has become a major security protection technology to detection potential attacks. In addition, BlockChain and Probe detection need to take into account the relationship between the various factors. We should develop a new probe detection technology that uses BlockChain to fine new pattern detection probes in cloud service security in the end. In this paper, we propose a probe detection using Fuzzy Cognitive Map(FCM) and Self Adaptive Module(SAM) based on service security using BlockChain technology.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.216-218
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• 2022

최근 공인인증서가 폐지되고 보다 발급이 간편하고 유효기간이 긴 사설인증서가 부상했다. 더불어 탈중앙화를 핵심 개념으로 하는 블록체인 기반 분산 신원 증명(Decentralized Identity, DID)기술이 대두되고 있다. 서비스 환경의 변화에 따라 사용자 인증 기술도 변화가 요구된다. 더욱이 메타버스라는 새로운 인터넷 환경이 조성되고 있는 바 현재 사용자 인증 기술의 동향을 살펴보고 미래에 사용자 인증이 나아갈 방향성을 제시하는 것은 의미가 있어 보인다. 본 논문에서는 사용자 인증 기술의 개요와 사용자 인증 기술의 변천과정을 시작으로 공개키 기반 구조(Public Key Infrastructure, PKI)와 분산 신원 증명을 중심으로 시장에서의 사용자 인증 기술의 동향을 살펴본다. 나아가 메타버스가 상용화되었을 시기에 사용자 인증 기술이 나아가야할 세가지 방향성(분산화, 플랫폼 초월, 생체 기반 인증 중심)을 제시한다.