• KNOM Review
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• v.22 no.3
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• pp.20-24
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• 2019

Blockchain is a distributed ledger-based technology where all nodes participating in the blockchain network are connected to the P2P network. When a transaction is created in the blockchain network, the transaction is propagated and validated by the blockchain nodes. The verified transaction is sent to peers connected to each node through P2P network, and the peers keep the transaction in the memory pool. Due to the nature of P2P networks, the number and type of transactions delivered by a blockchain node is different for each node. As a result, all nodes do not have the same memory pool. Research is needed to solve problems such as attack detection. In this paper, we analyze transactions in the memory pool before solving problems such as transaction fee manipulation, double payment problem, and DDos attack detection. Therefore, this study collects transactions stored in each node memory pool of Bitcoin and Ethereum, a cryptocurrency system based on blockchain technology, and analyzes how much common transactions they have using jacquard similarity.

• 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.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.5
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• pp.959-972
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• 2021

Decentralized Identity is based on the concept of self-sovereign identity, in which holders manage and provide their own credentials. However, a procedure is required to obtain credentials from issuers, and there is a risk of mess personal information leaking due to negligence of the issuers. In this paper, we propose a peer decentralized identity system based on Peer DID technology that allows only participants to verify their identity in 1:1 or 1:N small groups by matching the holder with the issuer. It is directly connected to a mobile device using short-range wireless communications such as bluetooth, and the holders create and provide their own credentials in person to the other party, thus fully realizing the self-sovereignty identity. The proposed system can simplify the identification process, improve security and privacy, and reduce costs. Furthermore, an extended architecture is possible to connect the proposed system and the distributed ledger to identify users in other domains. In the future, based on various technologies, it is also necessary to expand research on identity systems that can be utilized for human-to-thing and things-to-things authentication.

• Journal of Convergence for Information Technology
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• v.9 no.9
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• pp.44-51
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• 2019

Recently, various platforms utilizing blockchains have appeared. In order to develop the blockchain, it is required to improve related laws and institutions. In this respect, we analysis of the laws and systems related to domestic blockchains, draw out the limitations, and suggest directions for improvement. The research method was analyzed the literature and related laws through literature review. It is difficult to analyze the whole law and system at one time, so we examined the necessary laws and systems to revitalize the blockchain. It is confirmed that legal improvement is needed on the scope of electronic transactions and electronic financial transactions, electronic commerce, digital signatures, import and export, personal information protection, blockchain industry promotion and research. Through this, we expect a balanced development of effective blockchain revitalization and protection of national fundamental rights. Individual studies on the legal provisions and systems for each item in the future can be conducted.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.8
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• pp.2253-2280
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• 2024

In the upcoming era of transportation, a groundbreaking technology, known as vehicle-to-everything (V2X) communication, is poised to redefine our driving experience and revolutionize traffic management. Real-time and secure communication plays a pivotal role in V2X networks, with the decision-making process being a key factor in establishing communication and determining malicious nodes. The proposed framework utilizes a directed acyclic graph (DAG) to facilitate real-time processing and expedite decision-making. This innovative approach ensures seamless connectivity among vehicles, the surrounding infrastructure, and various entities. To enhance communication efficiency, the entire roadside unit (RSU) region can be subdivided into various sub-regions, allowing RSUs to monitor and govern each sub-region. This strategic approach significantly reduces transaction approval time, thereby improving real-time communication. The framework incorporates a consensus mechanism to ensure robust security, even in the presence of malicious nodes. Recognizing the dynamic nature of V2X networks, the addition and removal of nodes are aligned. Communication latency is minimized through the deployment of computational resources near the data source and leveraging edge computing. This feature provides invaluable recommendations during critical situations that demand swift decision-making. The proposed architecture is further validated using the "veins" simulation tool. Simulation results demonstrate a remarkable success rate exceeding 95%, coupled with a significantly reduced consensus time compared to prevailing methodologies. This comprehensive approach not only addresses the evolving requirements of secure V2X communication but also substantiates practical success through simulation, laying the foundation for a transformative era in transportation.

• Knowledge Management Research
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• v.23 no.1
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• pp.149-164
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• 2022

This paper analyzes the independent financial advisory business that is not yet active in Korea and proposes a plan to activate the independent financial advisory business using fintech technology. A bill was enacted in 2017 for the domestic independent financial advisory business, but it has not been activated much until now for various reasons. Although existing studies have proposed solutions in various ways, there is no clear solution yet. This paper proposes a new method of revitalizing the independent financial advisory business through fintech technology using the trust system that has recently attracted attention. Digital securities fintech technology using blockchain distributed ledger technology presents new possibilities in the real estate and music copyright markets, and related fintech venture companies continue to emerge in Korea. By combining these digital securities fintech technologies and the business process of ETF, a method was derived so that independent financial advisors can have their own financial products. The proposed model is more decentralized than the existing financial product sales structure, and presents the possibility of a protocol economy through a structure close to a private blockchain while complying with the existing financial order. This paper is meaningful in that it presented new solutions to completely different markets from information convergence perspectives on two completely different markets, and we hope that more business solutions will emerge through knowledge management activities that converge various perspectives in the future.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.4
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• pp.731-751
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• 2021

The Internet of Things is a huge group of devices communicating each other and the interconnection of objects in the network is a basic requirement. Choosing a reliable device is critical because malicious devices can compromise networks and services. However, it is difficult to create a trust management model due to the mobility and resource constraints of IoT devices. For the centralized approach, there are issues of single point of failure and resource expansion and for the distributed approach, it allows to expand network without additional equipment by interconnecting each other, but it has limitations in data exchange and storage with limited resources and is difficult to ensure consistency. Recently, trust management models using fog nodes and blockchain have been proposed. However, blockchain has problems of low throughput and delay. Therefore, in this paper, a trust management model for selecting reliable devices in a fog-based IoT environment is proposed by applying IOTA, a blockchain technology for the Internet of Things. In this model, Directed Acyclic Graph-based ledger structure manages trust data without falsification and improves the low throughput and scalability problems of blockchain.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.1
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• pp.185-194
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• 2018

This study investigates the limitations of blockchain technology and the ways to improve it by using Delphi technique. Limit factors and improvement measures are classified into technology, service, and legal system. First, from a technical point of view, lack of standardization of the technology, insufficiency of integration, lack of scalability, unclear cancellation or correction policy, excessive cost of transaction verification, insufficient personal information protection and not enough to respond to hacking defense were the limiting factors. In order to improve these, the followings; ensuring standardization, securing integration and scalability, establishing cancellation of each applicable data, establishment of correction policy, efficiency of verification cost, the protection of personal information and countermeasure against hacking are provided. The related technology development and countermeasures must be established to effectively introduce the blockchain technology to the market. Second, in the early stage of blockchain service, it showed lack of utilization of the blockchain, security threat, shortage of skilled workers, and lack of legal liability. As a solution to these problems, it is necessary to suggest various applications, against security threat, training professional manpower, and securing legal responsibility. It should also provide a foundation for providing institutionally stable services. Third, from as legal system point of view, inadequate legal compliance, lack of relevant regulation, and uncertainty in the regulation were the limiting factors. Therefore establishing a legal system, which is the most important area for activating the service, should be accompanied by the provision of legal countermeasures, clearness of regulations and measures to be taken by relevant governmental authorities. This study will contribute as a reference for a research, related to the blockchain.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.3
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• pp.513-525
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• 2020

Until today, the personal information of subjects has been centralized in many companies or institutions. However, in recent days, the paradigm has gradually changed in the direction that subjects control their personal information and persue their self-sovereignty. Globally, individual data sovereignty is strengthened by the European Union's General Data Protection Regulation(GDPR) and the US California Consumer Privacy Act(CCPA). In Korea, a few alliances consist of various companies are creating technology research and service application cases for decentralized ID service model. In this paper, the current decentralized ID service model and its limitations are studied, and a improved decentralized ID service model that can solve them is proposed. The proposed model has a function of securely storing decentralized ID to the third party and a linkage function that can be interoperated even if different decentralized ID services are generated. In addition, a more secure and convenient model by identifying the security threats of the proposed model and deriving the security requirements, is proposed. It is expected that the decentralized ID technology will be applied not only to the proof of people but also to the device ID authentication management of the IoT in the future.

• 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.