• Electronics and Telecommunications Trends
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• v.35 no.5
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• pp.134-138
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• 2020

Blockchain is an enabling technology for managing data with high trust and transparency among connected computers. Blockchain emerged with the advent of the Bitcoin cryptocurrency, and then, evolved as general-purpose platforms such as Ethereum, EOS, R3 Corda, and IBM Hyperledger Fabric. The application of blockchain covers a broad range of areas such as fintech, decentralized identity, distribution, real estate trading, games, and drone air traffic management. Smart contracts are indispensable for constructing blockchain services. This survey classifies smart contract languages by their features and shows their differences from existing general-purpose programming languages.

• Journal of the Korea Society of Computer and Information
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• v.25 no.2
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• pp.231-239
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• 2020

Cryptocurrency, represented by Bitcoin, initially received little public attention, but recently raised global cryptocurrency investments with recognition of future value. The academic interest in cryptocurrency lies elsewhere. This is because the future value of cryptocurrency is likely to be highly applicable to the technology underlying cryptocurrency. The technology is the blockchain. The purpose of this study is to find out what factors influence logistics companies to adopt blockchain technology. Based on the TOE frame, this study presented expected profit, organizational readiness, technology compatibility, and competitive pressure as factors of adoption of blockchain technology. And the effects of these factors on the adoption intention of logistics companies were analyzed empirically. A survey was conducted on Korean logistics companies. Analysis of the collected data showed that expected profit, organizational readiness, technology compatibility, and competitive pressures influence the intention to adopt blockchain technology. Among them, however, expected profit and organizational readiness were found to have the greatest influence on adoption intention.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.12
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• pp.159-168
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• 2020

The cryptocurrency market has received immense consideration in media and academia since the beginning of 2013 because of its huge price fluctuation. This study focuses on Arab investors who invest in the cryptocurrency market by investigating the influence of behavioral finance factors on investment decisions in the cryptocurrency market. A quantitative approach was used by employing a snowball sampling method through 112 questionnaires. The results show that herding theory, prospect theory, and heuristic theory have a significant effect on investors' investment decisions in the cryptocurrency market. This emphasizes the significant role of the proposed behavioral factors as determinants of the investors' investment decisions. This study contributes to the existing research by consolidating the results of different researches in this study. It also contributes to the investors' understanding of the dynamics of the cryptocurrency market and it enhances the ability to make informed decisions based on their understanding. The implication of the findings will prepare hit and run investors to be progressively prepared to stay in the cryptocurrency market and develop their abilities on the most proficient method to settle on sound venture choices. Furthermore, the findings of this study will encourage financial specialists to realize that information on the traditional finance theory is not adequate to excel in the cryptocurrency market.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.4
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• pp.1020-1041
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• 2024

With the development of covert communication technologies, the number of covert communication technologies using blockchain as a carrier is increasing. However, using the transaction amount of digital currency as a carrier for covert communication has problems such as low embedding rate, large consumption of transaction amount, and easy detection. In this paper, firstly, by experimentally analyzing the distribution of bitcoin transaction amounts, we determine the most suitable range of amounts for matrix decomposition. Secondly, we design a novel matrix decomposition method that can successfully decompose a large amount matrix into two small amount matrices and utilize the elements in the small amount matrices for covert communication. Finally, we analyze the feasibility of the novel matrix decomposition method in this scheme in detail from four aspects, and verify it by experimental comparison, which proves that our scheme not only improves the embedding rate and reduces the consumption of transaction amount, but also has a certain degree of resistance to detection.

• Journal of the Institute of Convergence Signal Processing
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• v.20 no.4
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• pp.218-225
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• 2019

Since the publication of Satoshi Nakamoto's white paper on Bitcoin in 2008, blockchain is in the spotlight as one of the core technologies of the Fouth Industrial Revolution, which can be used in various industries beyond simple cryptocurrency. various researches and developments are being conducted worldwide to utilize blockchain technology, and a global blockchain consortium is formed. In addition, attempts are being made to apply to various industries such as logistics, distribution, and medical care as well as the financial sector. However, blockchain tecnology developments still do not reach the level that meets these concerns and expectations. In this paper, we presents a comprehensive overview of blockchain technology by giving its brief concepts, consensus algorithms, standardization, and security threats.

• 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 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 Industrial Convergence
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• v.21 no.8
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• pp.51-58
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• 2023

Blockchains have recently struggled to design for the ideal distributed trust networks by solving scalability trilemma. However, local conflicts between some countries lead to imbalance on energy distribution. Besides, blockchain networks (e.g., Bitcoin) currently consume enormous energy for transaction and mining. The existing data volume based trust model evaluated an increasing blockchain size better than Lubin's trust model in scalability trilemma. In this paper, we propose a scalability based energy model to evaluate sustainability for blockchain networks, considering energy consumption for transaction, time duration, and the blockchain size of growing blockchain networks. Through the rigorous numerical analysis, we compare the proposed scalability based energy model with the existing model for the satisfaction and optimal blockchain size. Thus, the scalability based energy model will provide an assessment tool to choose the proper blockchain networks to solve scalability trilemma problem and prove sustainability.

• Journal of Internet Computing and Services
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• v.23 no.3
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• pp.21-33
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• 2022

This paper is to suggest the secure secret sharing system in order to outstandingly reduce the damage caused by the leakage of the corporate secret. This research system is suggested as efficient P2P distributed system kept from the centrally controlled server scheme. Even the bitcoin circulation system is also based on P2P distribution scheme recenly. This research has designed the secure circulation of the secret shares produced by Threshold Shamir Secret Sharing scheme instead of the shares specified in the torrent file using the simple, highly scalable and fast transferring torrent P2P distribution structure and its protocol. In addition, this research has studied to apply both Shamir Threshold Secret Sharing scheme and the securely strong multiple user authentication based on Collaborative Threshold Autentication scheme. The secure transmission of secret data is protected as using the efficient symmetric encryption with the session secret key which is safely exchanged by the public key encryption. Also it is safer against the leakage because the secret key is effectively alive only for short lifetime like a session. Especially the characteristics of this proposed system is effectively to apply the threshold secret sharing scheme into efficient torrent P2P distributed system without modifying its architecture of the torrent system. In addition, this system guaranttes the confidentiality in distributing the secret file using the efficient symmetric encryption scheme, which the session key is securely exchanged using the public key encryption scheme. In this system, the devices to be taken out can be dynamically registered as an user. This scalability allows to apply the confidentiality and the authentication even to dynamically registerred users.

• Economic Analysis
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• v.27 no.1
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• pp.67-90
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• 2021

This study found an interesting fact that the nonlinear relationship structure between volatility and trading volume changed before and after the COVID-19 pandemic according to empirical analysis using Bitcoin (BTC) market data that sensitively reflects investors' trading behavior. That is, their relationship appeared positive (+) in a stable market state before COVID-19 pandemic, as in theory based on the information flow paradigm. In a state under severe market stress due to COVID-19 pandemic, however, their dependence structure changed and even negative (-). This can be seen as a consequence of increased market stress caused by COVID-19 pandemics from a behavioral economics perspective, resulting in structural changes in the asset market and a significant impact on the nonlinear dependence of volatility and trading volume (in particular, their dependence at extreme quantiles). Hence, it should be recognized that in addition to information flows, psychological phenomena such as behavioral biases or herd behavior, which are closely related to market stress, can be a key in changing their dependence structure. For empirical analysis, this study performs a test of Ross (2015) for detecting a structural change, and proposes a Copula Regression Quantiles (CRQ) approach that can identify their nonlinear relationship structure and the asymmetric dependence in their distribution tails without the assumption of i.i.d. random variable. In addition, it was confirmed that when the relationship between their extreme values was analyzed by linear models, incorrect results could be derived due to model specification errors.