• Journal of Distribution Science
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• v.17 no.11
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• pp.93-101
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• 2019

Purpose: Blockchain technology suggests ways to solve the problems in the existing industry. Among them, Cryptocurrency system, which is an element of Blockchain technology, is a very important factor for operating Blockchain. While Blockchain cryptocurrency has attracted attention, studies on cryptocurrency prices have been mainly conducted, however previous studies mainly conducted on Bitcoin prices. On the other hand, in the context of the creation and trading of various cryptocurrencies based on the Blockchain system, little research has been done on cryptocurrencies other than Bitcoin. Hence, this study attempts to find variables related to the prices of Dash, Litecoin, and Monero cryptocurrencies using machine learning techniques. We also attempt to find differences in the variables related to the prices for each cryptocurrencies and to examine machine learning techniques that can provide better performance. Research design, data, and methodology: This study performed Dash, Litecoin, and Monero price prediction analysis of cryptocurrency using Blockchain information and machine learning techniques. We employed number of transactions in Blockchain, amount of generated cryptocurrency, transaction fees, number of activity accounts in Blockchain, Block creation difficulty, block size, umber of created blocks as independent variables. This study tried to ensure the reliability of the analysis results through 10-fold cross validation. Blockchain information was hierarchically added for price prediction, and the analysis result was measured as RMSE and MAPE. Results: The analysis shows that the prices of Dash, Litecoin and Monero cryptocurrency are related to Blockchain information. Also, we found that different Blockchain information improves the analysis results for each cryptocurrency. In addition, this study found that the neural network machine learning technique provides better analysis results than support-vector machine in predicting cryptocurrency prices. Conclusion: This study concludes that the information of Blockchain should be considered for the prediction of the price of Dash, Litecoin, and Monero cryptocurrency. It also suggests that Blockchain information related to the price of cryptocurrency differs depending on the type of cryptocurrency. We suggest that future research on various types of cryptocurrencies is needed. The findings of this study can provide a theoretical basis for future cryptocurrency research in distribution management.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.4
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• pp.179-188
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• 2018

Recently, blockchain technology has been recognized as one of the most important issues for the 4th Industrial Revolution which can be represented by Artificial Intelligence and Internet of Things. Cryptocurrency, named Bitcoin, was the first successful implementation of blockchain, and it triggered the emergence of various cryptocurrencies. In addition, blockchain technology has been applied to various applications such as finance, healthcare, manufacturing, logistics as well as public services. Distributed consensus algorithm is an essential component in blockchain, and it enables all nodes belonging to blockchain network to make an agreement, which means all nodes have the same information. For example, Bitcoin uses a consensus algorithm called Proof-of-Work (PoW) that gives possession of block generation based on the computational volume committed by nodes. However, energy consumption for block generation in PoW has drastically increased due to the growth of computational performance to prove the possession of block. Although many other distributed consensus algorithms including Proof-of-Stake are suggested, they have their own advantages and limitations, and new research works should be proposed to overcome these limitations. For doing this, above all things, we need to establish an evaluation method existing distributed consensus algorithms. Based on this motivation, in this work, we suggest and analyze assessment items by classifying them as efficiency and safety perspectives for investigating existing distributed consensus algorithms. Furthermore, we suggest new assessment criteria and their implementation methods, which can be used for a baseline for improving performance of existing distributed consensus algorithms and designing new consensus algorithm in future.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.1
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• pp.103-111
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• 2017

Recently, new variants of Ransomware are becoming a new security issue. Ransomware continues to evolve to avoid network of security solutions and extort users' information to demand Bitcoin using social engineering technique. Ransomware is damaging to users not only in Korea but also in all around the world. In this thesis, it will present research solution to prevent and cope from damage by new variants Ransomware, by studying on the types and damage cases of Ransomware that cause social problems. Ransomware which introduced in this paper, is the most issued malicious code in 2016, so it will evolve to a new and more powerful Ransomware which security officers cannot predict to gain profit. In this thesis, it proposes 4 methods to prevent the damage from the new variants of Ransomware to minimize the damage and infection from Ransomware. Most importantly, if user infected from Ransomware, it is very hard to recover. Thus, it is important that users understand the basic security rules and effort to prevent them from infection.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.4
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• pp.637-659
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• 2021

Since the creation of the first Bitcoin blockchain in 2009, the number of cryptocurrency users has steadily increased. However, the number of hacking attacks targeting assets stored in these users' cryptocurrency wallets is also increasing. Therefore, we evaluate the security of the wallets currently on the market to ensure that they are safe. We first conduct threat modeling to identify threats to cryptocurrency wallets and identify the security requirements. Second, based on the derived security requirements, we utilize attack trees and Bayesian network analysis to quantitatively measure the risks inherent in each wallet and compare them. According to the results, the average total risk in software wallets is 1.22 times greater than that in hardware wallets. In the comparison of different hardware wallets, we found that the total risk inherent to the Trezor One wallet, which has a general-purpose MCU, is 1.11 times greater than that of the Ledger Nano S wallet, which has a secure element. However, use of a secure element in a cryptocurrency wallet has been shown to be less effective at reducing risks.

• Journal of Industrial Convergence
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• v.18 no.6
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• pp.147-154
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• 2020

It is difficult to educate the overall operation of public and private blockchains with different characteristics. Recently, most education for blockchain is targeted at public blockchains such as Bitcoin and Ethereum. However, in an actual business environment, a private blockchain such as HyperLedger Fabric is used because access to corporate data is controlled through user authentication. In the case of HLF-based education, it is necessary to understand various components that are not in the public blockchain, such as peers, orderers, and channels. In this paper, a lab framework for HLF is designed for an efficient and systematic understanding of the functions and operations. The framework consists of HLF network, chaincode, and decentralized software control functions. Through the framework, the network configuration, distribution and activation of chaincode, and dApp execution process were checked step by step, and it was very easy to understand the overall flow for blockchain services. In addition, it is expected that a systematic understanding of the overall flow will be possible even in future network expansion.

• Journal of Information Technology Services
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• v.16 no.2
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• pp.33-44
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• 2017

The financial industry recently introduces several issues for utilizing the blockchain technology as the core infrastructure of future finance. Blockchain, first introduced as the underlying technology of Crypto-currencies, Bitcoin is a technology that can ensure the integrity and reliability of data by verifying, recording, and storing data jointly in the network without a central administration organization or a manager. This blockchain has its potential power as a technology for issuing digital currencies, providing transparency, and securing record management, that is expected to be useful in the financial sector. At the same time, considering the characteristics of financial transactions which emphasize privacy, questions are raised about whether a blockchain structure in which information is distributed and shared among participants can be successful. How will we support to implement the potential of the blockchain in order to change the paradigm of the financial industry? How can we manage the side effects of blockchain effectively? Such a policy discussion is necessary. This study introduces the meaning of the blockchain technology, various utilization attempts, and possible problems facing technology from the viewpoint of financial industry, and suggests a policy direction for utilizing this technology as a catalyst to the progress of the financial industry or as a new technology power.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.8
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• pp.4093-4107
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• 2019

Proof of Work (PoW) based blockchains have limitations in throughput, time consumption, and energy efficiency. In these systems, a miner will consume significant time and resources to obtain a reward for contributing to the blockchain. To overcome these limitations, recent research on blockchains are focused on accelerating the speed, scalability, and enhancing the security level. By enhancing specific procedures of blockchain system, the level of data integrity supported by the blockchain can become more robust, and efficient. In this paper, a new blockchain consensus model based on the Bryllite Consensus Protocol (BCP) is proposed to support a hyper-connected massively multiplayer online game (MMOG) ecosystem. The BCP scheme enables users to participate directly in new consensus processes through a Proof of Participation (PoP) algorithm. In this model, the consensus algorithm has a simpler form while maintaining high security level. In addition, because the BCP scheme gives users an equal chance to make a contribution to the blockchain, rewards are distributed in an equal fashion, which motivates user participation. The analysis of the proposed scheme is applied to the Bryllite consortium blockchain system (homed in Hong Kong), which is a new blockchain network developed for international game industries, gamers, and game events.

• 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.

• 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.

• 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.