• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.10
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• pp.1398-1404
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• 2018

The Blockchain technology could represent a solution to unexpected problems. In modern society, the domain of value has become diversified. The Crypto currency would replace the area that conventional currency could not function. The Japanese government recognized the Bitcoin as an official currency from April 2017 through amendment of the Money Transfer Act in 2016, and has been leading the related regulation policy recently. This paper examines the policy strategy of the Japanese government that is leading the current policy related to the Crypto currency market. The sequence of this paper is as follows: Coordination Process of Japanese Government's Crypto currency Policy of Special Mission Committee on IT Strategy as a Coordinator, Amendment of the Fund Settlement Act and the Establishment of a Self-Regulation Organizations in Crypto currency and Japan's Crypto currency Taxation and Supplementary System.

• Convergence Security Journal
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• v.18 no.3
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• pp.45-51
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• 2018

Recently, Crypto currency has evolved along with Blockchain technology and the voice of concern and concern of many people. Global nations that consider the use of Crypto currency are prudent in their protection of their economies due to legal regulations and institutional arrangements, and are watching the trends of various Crypto currency. Among them, Crypto currency is very popular because it can acquire money through cryptographic computation. However, there is a need to consider the impact of high-quality computing resources and the consumption of many electrical energy on global warming. Therefore, this study investigated the calculation of electric energy consumption and Carbon Dioxide Emissions, data and cases related to the mining of Crypto currency, examined variable factors. This will be used as research data that will respond to the 4th industrial revolution, such as the presentation of a more positive development direction of Crypto currency, and the development of various related technologies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.287-294
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• 2018

This thesis covers legal aspects of the crypto-currency exchange and the legal rights of crypto-currencies holders. Unlike financial markets in which central authorities or intermediaries determine the validity of transactions and manage records, crypto-currency markets utilize a decentralization system based on block chain technology. Such distinct characteristics distinguish crypto-currency from currency, notes, or financial instruments. Therefore, we need to check closely the legal principles that are applicable to crypto-currency. Crypto-currency users possess rights indirectly through the crypto-currency exchange. However, we should look at whether crypto-currency can be an object of ownership. This research found that legal protection for crypto-currency exchanges are limited. Domestic laws have many shortcomings to protect users' rights. This study found that users who incurred damages due to internet computation errors at exchanges require a protective system like stock markets. Therefore, studies on the legal controls and system regulations are required to protect users' rights. Also, crypto-currency information exchanges keep inside and protections for users' private information need to be further examined.

• Journal of Information Processing Systems
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• v.15 no.3
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• pp.457-463
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• 2019

The blockchain and crypto currency has become one of the most essential components of a communication network in the recent years. Through communication networking, we browse the internet, make VoIP phone calls, have video conferences and check e-mails via computers. A lot of researches are being conducting to address the blockchain and crypto currency challenges in communication networking and provide corresponding solutions. In this paper, a diverse kind of novel research works in terms of mechanisms, techniques, architectures, and frameworks have been proposed to provide possible solutions against the existing challenges in the communication networking. Such novel research works involve thermal load capacity techniques, intelligent sensing mechanism, secure cloud computing system communication algorithm for wearable healthcare systems, sentiment analysis, optimized resources.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.5
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• pp.812-817
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• 2018

Blockchain technology removes the central system and connects each block throughout every person. This paper proposes new method to exploit the blockchain feature to apply existing donation system. In the current system, the donator does not donate to poor neighbor which means donator must have to donate some donate organization. The donator does not recognize how the donation has been spent after donation. In this case, we can solve that problem by using the blockchain where the donator can watch how the money works and everyone can browse the account history. To make a virtual fundraising box based on blockchain technology, donator sends some money at virtual account and exchanges the money to crypto-currency. Donator can use crypto-currency which is donate to poor neighbor that poor neighbor can exchanges crypto-currency to the money. Through this proposed system, the donation is managed by secure and transparent blockchain system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.1
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• pp.187-194
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• 2019

Ever since the world's largest Bitcoin Echange, (Mt. Gox), was closed in March 2014 due to the series of hacking, still many other Exchages incl. recent Coinale in Korea have been attacked. Those hacking attempts never stopped and have caused significant threats to the overall industry of Crypto Currency and resulted in the loss of individual investors' asset. The DEX (Decentralized Exchange) has been proposed as a solution to fix the security problem at the Exchange, but still it is far away to resolve all issues. Therefore, this paper firstly analyzes security threats against existing Crypto Currency Exchanges and secondly derives security requirements for them. To do that it proposes a secure and distributed Crypto Currency Transaction Model through Personal Security devices as a solution. The paper also proves this new attempt by demonstrating its unique modelling; ultimately by adopting this modeling into Crypto Exchange is to avoid potential security threats.

• Journal of Korea Society of Digital Industry and Information Management
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• v.15 no.1
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• pp.77-86
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• 2019

Comparative analysis to secure safety of Blockchain Many investors have invested in virtual currency such as bit coins as a new investment due to increased popularity of virtual currency around the world. Also, virtual currency such as bit coin has a security technology and it has been relatively proved. popularity of virtual currency is rising as a new investment alternative because of this reason. This paper focused on the block chain's transparency and security of distributed ledger technology, which is relatively safe without third party's intervention. Many governments and companies around the world are developing and working on block chain technological development to introduce due to these reasons However, there are some suggestion that block chain has minor risks to its security. In this paper, it will examine security vulnerabilities from importance of security of Blockchain which relates to transactions of Bitcoin which stored by governments and companies around the world. This paper will propose measure which will improve safety and efficiency of Blockchain technology such as the existing Blockchain method, Blockchain proposal, traceability and awareness about hacking.

• Journal of Information Processing Systems
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• v.14 no.4
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• pp.837-850
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• 2018

Bitcoin is a decentralized crypto-currency, which is based on the peer-to-peer network, and was introduced by Satoshi Nakamoto in 2008. Bitcoin transactions are written by using a scripting language. The hash value of a transaction's script is used to identify the transaction over the network. In February 2014, a Bitcoin exchange company, Mt. Gox, claimed that they had lost hundreds of millions US dollars worth of Bitcoins in an attack known as transaction malleability. Although known about since 2011, this was the first known attack that resulted in a company loosing multi-millions of US dollars in Bitcoins. Our reason for writing this paper is to understand Bitcoin transaction malleability and to propose an efficient solution. Our solution is a softfork (i.e., it can be gradually implemented). Towards the end of the paper we present a detailed analysis of our scheme with respect to various transaction malleability-based attack scenarios to show that our simple solution can prevent future incidents involving transaction malleability from occurring. We compare our scheme with existing approaches and present an analysis regarding the computational cost and storage requirements of our proposed solution, which shows the feasibility of our proposed scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.8
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• pp.3243-3256
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• 2020

Recent years have shown a great interest of public in buying and selling of crypto/digital currency. With hundreds of digital currencies in financial market, bitcoin remains the most widely used, adapted, and accepted currency around the world. However, the critics of bitcoin still consider it a threat to modern day power usage. This paper discusses the important pitfalls, pros, and cons related to bitcoin's energy consumption. The paper begins by highlighting the flexibilities cryptocurrency can bring to online money transfers compared to traditional 'fiat' architecture. Then, the focus of the paper entirely remains on listing various facts related to bitcoin's energy utilization including a brief description of several emerging approaches for energy optimization. This paper is concluded by revealing key current challenges associated to bitcoin's energy usage.

• KNOM Review
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• v.24 no.2
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• pp.1-12
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• 2021

Recently, research on CBDC (Central Bank Digital Currency) has been actively conducted for various reasons by countries around the world. In addition, with the dazzling development of blockchain technology, blockchain technology is being adopted in CBDC. In this paper, we propose a blockchain-based CBDC system that can be effectively used in the traditional banking system. We also analyze the requirements of CBDC and suggest ways to commercialize CBDC. We present a system design and implementation method, especially in terms of compatibility, interoperability, and privacy.