• KIPS Transactions on Computer and Communication Systems
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• v.11 no.2
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• pp.51-58
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• 2022

Blockchain technology is a system in which data from users participating in blockchain networks is distributed and stored. Bitcoin and Ethereum are attracting global attention, and the utilization of blockchain is expected to be endless. However, the need for blockchain data privacy protection is emerging in various financial, medical, and real estate sectors that process personal information due to the transparency of disclosing all data in the blockchain to network participants. Although studies using smart contracts, homomorphic encryption, and cryptographic key methods have been mainly conducted to protect existing blockchain data privacy, this paper proposes data privacy using matrix character relocation techniques differentiated from existing papers. The approach proposed in this paper consists largely of two methods: how to relocate the original data to matrix characters, how to return the deployed data to the original. Through qualitative experiments, we evaluate the safety of the approach proposed in this paper, and demonstrate that matrix character relocation will be sufficiently applicable in private blockchain environments by measuring the time it takes to revert applied data to original data.

• Journal of Digital Convergence
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• v.17 no.6
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• pp.219-227
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• 2019

This study aims to examine Blockchain research trend using bibliometrics-based network analysis. The data were collected from WoS, Scopus, Korea Citation Index and National science & Technology Information Service, from 2009 to 2018. As results, the number of publications has started increasing rapidly from 2017 and it showed the initial stage of formation of coauthor network. Words often used in the title of the publications were related to application development, controversy and technology development. In addition, the majority of domestic papers are in the subject of social science, while international papers tend to focus on engineering issues. The results of the temporal analysis show that Korean researchers' block chain 3.0 started in 2017 and are rapidly increasing in 2018. The number of citations was associated with publication year in a statistically signifiant way. By examining these research trends, we hope that this paper can be a useful basis for the development of blockchain. Future research is expected to reveal more clearly the knowledge structure and characteristics of blockchain around the world.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.1
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• pp.5-14
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• 2018

With the advance of the 4th industrial revolution, Internet of Things (IoT) technology is actively being studied. In the era of the IoT, a decentralized operation is required to reduce load on servers and enable autonomous IoT data communication rather than focusing on centralized operation of being server client structures. This paper analyzes the security of a blockchain, a new form of distributed database platform that supports integrity and permanence of data. To achieve this, we divide the blockchain's major operations into a consensus process, network communication process, and key management process, and then describe possible attacks and countermeasures in each process. We also describe the attack occurred in typical cryptocurrency platforms such as Bitcoin and Ethereum.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.290-292
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• 2019

Since the advent of blockchain and bitcoin, decentralization has been accelerating around the world as a public blockchain ethereum with smartcontract has begun. Developers can use Ethereum's blockchain development platform to develop "distributed applications" (DApp) running on a decentralized P2P network, and various types of devices from IoT to mobile can participate in a block-chain distributed environment have. Using Ethereum's blockchain development platform, developers can develop "Decentralized Application (DApp)" that run on a decentralized P2P network and various types of devices from IOT to mobile can participate in distributed blockchain environments. There are many ways to interact with the blockchain and the smart contract, but users tend to prefer the mobile methods due to their convenience and accessibility advantages. Therefore, the author developed an Android based voting DApp and researched related issues. Since the current development methods of DApp are not adequately researched and standardized, efficient methods for developing user-friendly DApp were studied. Because DApp has to spend a certain amount of fees to interact with blockchain, it has intensively investigated the gas problem of Smart Contract code and the security problem of code, and author would like to introduce it in this paper.

• Journal of the Korean Society for information Management
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• v.38 no.3
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• pp.23-39
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• 2021

This study aims to explore research trends in Blockchain studies in South Korea using dynamic topic modeling and network analysis. To achieve this goal, we conducted the university & institute collaboration network analysis, the keyword co-occurrence network analysis, and times series topic analysis using dynamic topic modeling. Through the university & institute collaboration network analysis, we found major universities such as Soongsil University, Soonchunhyang University, Korea University, Korea Advanced Institute of Science and Technology (KAIST) and major institutes such as Ministry of National Defense, Korea Railroad Research Institute, Samil PricewaterhouseCoopers, Electronics and Telecommunications Research Institute that led collaborative research. Next, through the analysis of the keyword co-occurrence network, we found major research keywords including virtual assets (Cryptocurrency, Bitcoin, Ethereum, Virtual currency), blockchain technology (Distributed ledger, Distributed ledger technology), finance (Smart contract), and information security (Security, privacy, Personal information). Smart contracts showed the highest scores in all network centrality measures showing its importance in the field. Finally, through the time series topic analysis, we identified five major topics including blockchain technology, blockchain ecosystem, blockchain application 1 (trade, online voting, real estate), blockchain application 2 (food, tourism, distribution, media), and blockchain application 3 (economy, finance). Changes of topics were also investigated by exploring proportions of representative keywords for each topic. The study is the first of its kind to attempt to conduct university & institute collaboration networks analysis and dynamic topic modeling-based times series topic analysis for exploring research trends in Blockchain studies in South Korea. Our results can be used by government agencies, universities, and research institutes to develop effective strategies of promoting university & institutes collaboration and interdisciplinary research in the field.