• The Journal of the Korea Contents Association
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• v.20 no.5
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• pp.11-22
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• 2020

The academic credit banking system is an educational system to implement a lifelong learning society. Students who meet the requirements of this system can achieve academic degrees equivalent to those of junior colleges or four-year universities. Credits and degree information of these students are recorded and managed by the central institution. However, this system can cause security problem such as hacking due to centralized management. In this paper, we propose an academic credit banking system which can manage credits and degree information based on blockchain technology. In the proposed system, credits and degree information are stored in block and managed in the public ledger in a permanent manner. Blocks are connected in the form of blockchain on a distributed network to improve security problems such as hacking and manipulation. Also, the efficiency of credit bank management can be increased because the functions of the central institution are distributed to the network participants. The prototype of the proposed system was implemented on the Go-Ethereum platform and experimentally verified the blockchain information among participating organizations using smart contracts.

• Journal of Digital Convergence
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• v.15 no.8
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• pp.203-212
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• 2017

The National Housing Bond Information Relay System is a representative financial information relay system in which institutions are connected with center system. A centralized structure is expensive to construct and operate center, and there is a problem that all networks are disconnected when a failure occurs in the center system. In this paper, we propose the national housing bond information relay system model based on Blockchain technology that can process information safely and efficiently. The proposed model constructs a Blockchain network so that each institution that processes the national housing bond information can transmit information safely, and each institution manages the same distributed ledge by a smart contract. The proposed model can reduce the cost because it can process complicated national housing bond transaction information without a relay center, and a network usage and disk usage decreased by 1.7% and 8.53%.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.114-115
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• 2018

Recently in Bitcoin raising a social issue is sometimes called a horizontal and decentralized digital virtual currency utilizing the Blockchain technology such as a type of password currency. On the other hand, the Blockchain, which is a distributed ledger shared on P2P networks and it was first used in Bitcoin. These technologies are regarded as technologies that can be applied diversely in other fields, and are attracting high social interest. Looking at recent trends in the virtual currency market such as Bitcoin, price movements have increased since the Japanese government approved the virtual currency as a means of settlement last year. Therefore, we try to present theoretical practical suggestion through the viewpoint of the Blockchain technology which is core technology of Bitcoin based on innovative technology.

• International Journal of Computer Science & Network Security
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• v.21 no.4
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• pp.255-263
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• 2021

Smart grid is a fully-automated, bi-directional, power transmission network based on the physical grid system, which combines sensor measurement, computer, information communication, and automatic control technology. Blockchain technology, with its security features, can be integrated with Smart Grids to provide secure and efficient power management and transmission. This paper dicusses the deployment of Blockchain technology in Smart Grid. It presents application areas and protocols in which blockchain can be applied to in securing smart grid. One application of each area is explored in detail, such as efficient peer-to-peer transaction, lower platform costs, faster processes, greater flexibility in power generation to transmission, distribution and power consumption in different energy storage systems, current barriers obstructing the implementation of blockchain applications with some level of maturity in financial services but concepts only in energy and other sectors. Wide range of energy applications suggesting a suitable blockchain architecture in smart grid operations, a sample block structure and the potential blockchain technicalities employed in it. Also, added with efficient data aggregation schemes based on the blockchain technology to overcome the challenges related to privacy and security in the smart grid. Later on, consensus algorithms and protocols are discussed. Monitoring of the usage and statistics of energy distribution systems that can also be used to remotely control energy flow to a particular area. Further, the discussion on the blockchain-based frameworks that helps in the diagnosis and maintenance of smart grid equipment. We have also discussed several commercial implementations of blockchain in the smart grid. Finally, various challenges have been discussed for integrating these technologies. Overall, it can be said at the present point in time that blockchain technology certainly shows a lot of potentials from a customer perspective too and should be further developed by market participants. The approaches seen thus far may have a disruptive effect in the future and might require additional regulatory intervention in an already tightly regulated energy market. If blockchains are to deliver benefits for consumers (whether as consumers or prosumers of energy), a strong focus on consumer issues will be needed.

• Journal of Convergence for Information Technology
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• v.11 no.11
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• pp.66-74
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• 2021

With the development of the Internet, user authentication technology that proves me online is improving. Existing ID methods pose a threat of personal information leakage if the service provider manages personal information and security is weak, and the information subject is to the service provider. In this study, as online identification technology develops, we propose a DID-based self-authentication model to prevent the threat of leakage of personal information from a centralized format and strengthen sovereignty. The proposed model allows users to directly manage personal information and strengthen their sovereignty over information topics through VC issued by the issuing agency. As a research method, a self-authentication model that guarantees security and integrity is presented using a decentralized identifier method based on distributed ledger technology, and the security of the attack method is analyzed. Because it authenticates through DID Auth using public key encryption algorithms, it is safe from sniffing, man in the middle attack, and the proposed model can replace real identity card.

• The Journal of the Convergence on Culture Technology
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• v.5 no.3
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• pp.55-60
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• 2019

It is true that Blockchain has been known as a core technology for cryptocurrency like bitcoin (BTC). It is caused by its rapid value rises. Now, one BTC is trading around 10,000 US dollars while it bought just less than one dollar at its first trading in May, 2010. Blockchain makes on-line transactions possible by the safe cryptocurrency swiftly based on P2P network and distributed public ledger while its on-line traffic is rapidly increasing. However, this technology has bigger potential in the fourth industrial revolution era and its application areas will be varied. The evolving intelligent information society needs to make new added value through utilizing, sharing and processing of useful digital information. Obstacles such as hacking and fraud often exist when transactions of digital properties, right transfers, etc. are done through digital network specialized with anonymity. It is expected that blockchain will be a definite solution in this regard. This paper addresses useful development directions and countermeasures for blokchain in the digital economy by analysis of its current status and issues.

• Journal of Korea Trade
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• v.23 no.6
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• pp.113-130
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• 2019

Purpose - This paper investigates applicability of blockchain based bill of lading under the current legal environment. Legal requirements of electronic bill of lading will be analyzed based on the Rotterdam Rules and recently enacted UNCITRAL Model Law on Electronic Transferable Records. Using comparative analysis with the previous registry model for electronic bill of lading, this paper examines the advantages of blockchain based bill of lading. Design/methodology - This research reviewed previous efforts for dematerializing bill of lading with its limitation. Main features of blockchain technology which can make up for deficiencies of registry model also be investigated to analyze whether these features can satisfy the requirements for the legal validity of the negotiable electronic transport record or electronic transferable records under the Rotterdam Rules and the MLETR. Findings - Main findings of this research can be summarized as follows: Blockchain system operated in an open platform can improve transparency and scalability in transfer of electronic bill of lading by assuring easy access for transaction. Distributed ledger technology of blockchain makes it more difficult to forge or tamper with transactions because all participants equally shares identical transaction records. Consensus mechanism and timestamp in a blockchain transaction guarantee the integrity and uniqueness of a transaction. These features are enough to satisfy the requirements of electronic transferable records under the Rotterdam Rules and MLTER. Originality/value - This study has significance in that it provided implications for the introduction of electronic bill of lading by analyzing whether the blockchain based electronic bill of lading model meets the legal requirements under the current legal system prepared prior to the introduction of blockchain technology, and by presenting the advantages of the blockchain based bill of lading model through comparative analysis with the existing registry model.

• Journal of Platform Technology
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• v.9 no.1
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• pp.46-57
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• 2021

Recently, research has been actively conducted to utilize blockchain technology in various fields. In particular, blockchain-based smart contracts are applied to various automation systems that require reliability as they have the characteristics of recording data in a distributed ledger environment to verify the integrity and validity of data. However, blockchain does not provide data access control and information security because data is shared among network participants. In this paper, we propose a user dynamic access control mechanism utilizing smart contracts in blockchain environments. The proposed mechanism identifies the user's contextual information when accessing data, allocating the user's role and dynamically controlling the data access range. This can increase the security of the system and the efficiency of data management by granting data access dynamically at the time of user authentication, rather than providing the same services in roles assigned to each user group of the network system. The proposed mechanism is expected to provide flexible authentication capabilities through dynamic data access control by users to enhance the security of data stored within blockchain networks.

• 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.