• Convergence Security Journal
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• v.19 no.2
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• pp.11-19
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• 2019

The blockchain is a technique for managing transaction data in distributed computing manner without the involvement of central trust authority. The blockchain has been used in various area such as manufacturing, culture, and public as well as finance because of its advantage of the security, efficiency and applicability. In the blockchain, it was considered safe against 51% attack because the adversary could not have more than 50% hash power. However, there have been cases caused by large-scale computing attacks such as 51% and selfish mining attack, and the frequency of these attacks is increasing. In addition, since the development of quantum computers can hold exponentially more information than their classical computer, it faces a new type of threat using quantum algorithms. In this paper, we perform the security analysis of blockchain attacks composing the large computing capabilities including quantum computing attacks. Finally, we suggest the technologies and future direction of the blockchain development in order to be safe against large-scale computing attacks.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.11
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• pp.332-338
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• 2020

The blockchain contains potential to contribute for the development of education, teaching and learning as it provides the basic technologies which can handle the data transparently and stably in reliability. Especially, blockchain technology can guarantee the transparency, stability and reliability on the data especially in managing longitudinal education data. This study designed the Badgechain service platform combining badges and blockchains. This service consists of Badgechain solution, Moodle LMS linked to Badgechain added with Badgechain service as a learning activity, and Badgechain Wallet site where badges issued by various agencies can be viewed and managed. This study was performed as a basic study on educational use of blockchain.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.2
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• pp.309-320
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• 2019

Blockchain has been developed as a key technology for many cryptocurrency systems such as Bitcoin. These days, blockchain technology attracts many people to adopt it to various fields beyond cryptocurrency systems for their information sharing and processing. However, with the development and increasing adoption of the blockchain, security incidents frequently happen in the blockchain systems due to their implementation flaws. In order to solve this problem, in this paper, we analyze the software vulnerabilities of Bitcoin and Ethereum, which are the most widely used blockchain applications in real world. For that purpose, we conduct an in-depth analysis of source code of them to detect software vulnerabilities, and examine an OS command injection attack exploiting the detected ones.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.11
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• pp.281-288
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• 2018

The block chain, which is characterized by a distributed ledger that stores the same data in several places, has various technical features including security and stability. Due to these characteristics, various researches are being conducted on the application of the block chain. In this paper, we consider the issues to be considered for applying the block chain to the Korea Real Estate Administration Intelligence System (KRAS). Based on this, we propose a block chain reference model for KRAS including a system configuration method and a consensus algorithm.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.07a
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• pp.41-44
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• 2019

4차 산업혁명 시대에 떠오르는 기술인 블록체인과 블록체인의 단점을 보완할 수 있는 분산된 파일 시스템 IPFS을 활용하여 새로운 형태의 웹툰 플랫폼 서비스 BlockToon을 개발하였다. 본 논문에서 개발한 BlockToon은 중앙 서버가 웹툰 정보와 파일을 관리하는 것이 아닌 작가가 파일에 대한 정보를 블록체인과 IPFS에 자유롭게 등록, 관리한다. 블록체인 특성상 수정 및 삭제가 불가능하기 때문에 블록체인에 등록된 웹툰의 정보는 저작권 증명이 가능하다. 또한 주요 데이터를 중앙 서버에서 관리하지 않으므로 중앙 서버 유지 비용이 절감된다.

• Annual Conference of KIPS
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• 2018.10a
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• pp.998-1000
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• 2018

데이터 무결성을 보장하는 블록체인은 IoT 환경과 같은 비금융 분야에서 활용이 증가되고 있으며 IoT 환경의 수집된 자료를 저장할 수 있는 단순한 인프라로 활용되고 있다. 이 논문에서는 산업사고 발생시 주요 원인에 대한 추적검증을 위해 산업현장에서의 환경정보를 블록체인에 저장하기 위한 센서자료 수집시스템을 기술한다. 본 개발 시스템은 허가형 블록체인 플랫폼인 HyperLedger Fabric을 사용하여 온도, 충격 및 영상데이터의 주요 특징을 요약하여 블록체인에 저장할 수 있도록 한다.

• Annual Conference of KIPS
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• 2023.05a
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• pp.209-211
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• 2023

ICT 기술을 통해 데이터를 수집하고 수집된 데이터를 활용하여 시민의 삶의 질을 향상시키는 스마트시티는 대표적으로 전기, 건물, 냉난방 시스템, 교통이 있다. 스마트시티의 교통 문제를 해결하기 위하여 IoV의 데이터를 활용할 수 있으나, IoV에 대한 네트워크 공격이 급증함에 따라 블록체인을 사용하여 데이터를 안전하게 수집하고 스마트시티에 활용하는 다양한 연구가 진행되고 있다. 본 논문에서는 스마트시티 환경의 IoV 시스템을 위한 블록체인 기반 차량 네트워크 보안 기술 연구 동향을 기술하고 향후 연구 방향을 제시한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.43-50
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• 2019

Block-chain enjoys technical advantages such as "robust security," owing to the structural characteristic that forgery is impossible, decentralization through sharing the ledger between participants, and the hyper-connectivity connecting Internet of Things, robots, and Artificial Intelligence. As a result, public organizations have highly positive attitudes toward the adoption of technology using block-chain, and the design of university information services is no exception. Universities are also considering the application of block-chain technology to foundations that implement various information services within a university. Through case studies of block-chain applications across various industries, this study designs an empirical model of an integrated information service platform that integrates information systems in a university. A basic road map of university information services is constructed based on block-chain technology, from planning to the actual service design stage. Furthermore, an actual empirical model of an integrated information service in a university is designed based on block-chain by applying this framework.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.759-764
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• 2021

Because sensitive and private information should be exchanged between electric vehicles and a V2G service provider, reliable communication channel is essential to operate Vehicle-to-Grid (V2G) system which considers battery of electric vehicles as a factor of smart grid. The block chain is a platform for cryptocurrency transaction and fully distributed database system running by only equivalent node in the network without help of any central management or 3^rd party. In this paper, the structure and operation method of the blockchain are investigated, and the application of the blockchain for the V2G system was also explained and analyzed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.6
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• pp.1607-1621
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• 2018

The financial industry, which guarantees a credible transaction and can not permit forgery of its transaction information, has hitherto adhered to a traditional centralized ledger management method. However, the blockchain technology has a decentralization which has been regarded as unsafe for the time being, and the more reliable transaction agreement and data integrity are guaranteed The world's financial industry and the IT world is causing the wave. Nevertheless, the inherent characteristics of the blockchain, such as the irreversibility of block information within a blockchain and the sharing of blocks between blockchain participants, can not avoid conflicts with the privacy laws. The purpose of this study is to investigate the problems related to deletion and the third party supply of personal information by focusing on these characteristics of the blockchain and to suggest the technical alternatives of the applicable blockchain and the improvement direction of the personal information protection law for using of blockchain technology.