• Electronics and Telecommunications Trends
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• v.33 no.1
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• pp.45-56
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• 2018

A Blockchain is a type of distributed ledger system that consists of a large number of nodes. A block is a container in which transactions are included, and the transactions can be recorded in chronological order by chaining blocks. To work properly, it is essential that the nodes in the Blockchain system have the same image of the chained-blocks. Blockchain systems use various types of consensus algorithms to achieve the same states among the nodes, and the fundamental elements in these algorithms are proof of work and the main chain selection policy, particularly in permissionless Blockchain systems. However, consensus algorithms for permissioned Blockchain systems can be completely different from those of permissionless blockchain systems. In this paper, we overview the basic working mechanism of consensus algorithms, and briefly introduce a few that are currently being applied.

• Journal of Information Processing Systems
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• v.16 no.2
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• pp.421-434
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• 2020

The development of digital technology has changed the lives of many people in terms of the velocity and convenience of completing tasks. This technology has also been applied to the process of voting, yet electronic voting is seldom used. The existing electronic voting scheme operates by applying various encryption algorithms. This type of electronic voting can be problematic since the administrator is given full authority. The administrator cannot always be trusted, and the contents of the ballot could be forged or tampered by a single point of failure. To resolve these problems, researchers continue to apply blockchain technology to electronic voting. Blockchain technology provides reliability and data integrity because all untrusted network participants have the same data. In this paper, we propose an electronic voting system that secures reliability by applying blockchain technology to electronic voting and ensures secret voting.

• Journal of the Korea Society of Computer and Information
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• v.23 no.1
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• pp.111-116
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• 2018

Recently, IoT and Big Data dealing with voluminous and complex sensitive information is one of the key issues in the era of the 4th industrial revolution. There have been a lot of studies to store the collected and processed sensitive information safely in storage data. Especially biometric information, if it is leaked and becomes identity theft, is hard to be corrected and results in serious event. To fix the problem, methods such as FIDO or KFTC have been proposed. In this paper, we propose a modified method of TTAK.KO-12.0098 according to the environment of this paper and propose a method of safely storing the generated disposable template in a block chain. We show that our method is better by comparing the existing method and the security analysis.

• International journal of advanced smart convergence
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• v.10 no.4
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• pp.198-205
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• 2021

With the development of blockchain technology, the scope of blockchain applications has expanded rapidly. Blockchain decentralization allows transaction participants to make transparent and safe transactions without a third trust agency. A distributed ledger-based system enables transparent and trusted business for anonymous users. For this reason, many companies apply blockchain to various fields such as logistics, electronic voting, and real estate. Despite this interest, there are still not enough case studies confirming the potential of blockchain as a concrete business model. Therefore, it is necessary to study how blockchain technology can change the existing business model and connect it to a new business model. In this paper, we propose blockchain-based business models and workflow types in various fields such as healthcare, logistics, and energy. We also present application cases. We expect to help companies apply blockchain to their business.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.3
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• pp.861-876
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• 2022

Cryptoassets such as Bitcoin and Ethereum are widely traded around the world. Cryptocurrencies are also transferred between investors. Cryptocurrency has become a new and attractive means of remittance. Thus, blockchain-based smart contracts also attract attention when central banks design digital currencies. However, it has been discovered that a significant amount of cryptoassets on blockchain are lost or stranded for a variety of reasons, including the loss of the private key or the owner's death. To address this issue, we propose a method for recoverable transactions that would replace the traditional transaction by allowing cryptoassets to be sent to a backup account address after a deadline has passed. We provide the computational workload required for our method by analyzing the prototype. The method proposed in this paper can be considered as a good model for digital currency design, including central bank digital currency (CBDC).

• ETRI Journal
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• v.45 no.6
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• pp.982-995
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• 2023

Technological innovation generates products, services, and processes that can disrupt existing industries and lead to the emergence of new fields. Distributed ledger technology, or blockchain, offers novel transparency, security, and anonymity characteristics in transaction data that may disrupt existing industries. However, research attention has largely examined its application to finance. Less is known of any broader applications, particularly in Industry 4.0. This study investigates academic research publications on blockchain and predicts emerging industries using academia-industry dynamics. This study adopts latent Dirichlet allocation and dynamic topic models to analyze large text data with a high capacity for dimensionality reduction. Prior studies confirm that research contributes to technological innovation through spillover, including products, processes, and services. This study predicts emerging industries that will likely incorporate blockchain technology using insights from the knowledge structure of publications.

• Journal of Information Technology Services
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• v.19 no.4
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• pp.125-138
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• 2020

This paper proposes a more advanced livestock insurance product by comparing the status of livestock management in Korea with Netherlands case. The project focused on blockchain technology, IoT based management manual and planned livestock insurance related to Insurtech. The livestock insurance policy automatically stores information on each block through sensors attached to livestock, so that the livestock manager carries out follow-up manual for each livestock. Blockchain technology contains numerous advantages such as distributed ledger and irreversibility. However, the sharing of transparent information can be a burden to the policyholder. To compensate it, new business model needs to be proposed to provide incentives to the policyholder. We focused on the data of Gyeonggi Province, which suffered the most from African swine fever (ASF) in Korea. The corresponding Insurtech based livestock insurance can enable policyholders and insurers to build trust by sharing objective and transparent information, and maximize their respective profits by enabling mutual control.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.4
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• pp.99-106
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• 2017

With the advent of virtual money such as bit coins, interest in the block chain is increasing. Block Chain is a technology that supports Distributed Ledger and is a versatile technology applicable to various fields. Currently, the block chain is conducting research for various applications such as virtual money, trade finance, marketplace, power market, image contents service, and IoT. The technologies that make up the block chain are smart contract, digital signature/hash function and consensus algorithm. And these technologies operate on P2P networks. In this paper, we have studied e-mail system based on the ethereum which is one of the block chain based technologies. Most legacy mail systems use SMTP and the POP3/IMAP protocol to send and receive e-mail, and e-mail use S/MIME to protect the e-mail. However, S/MIME is vulnerable to DDoS attacks because it is configured centrally. And it also does not provide non-repudiation of mail reception. To overcome these weaknesses, we proposed an e-mail system model based on ethereum. The proposed model is able to cope with DDoS attack and forgery prevention by using block chain based technology, and reliable recording and management among block chain participants are provided, so that it is possible to provide a non-repudiation function of e-mail transmission and reception.

• Journal of Information Technology Services
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• v.16 no.2
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• pp.1-20
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• 2017

A bitcoin-based technology named blockchain is garnering attention in various industries as a cost-effective measure in strengthening security and a reliable technology medium. Blockchain technology will play a critical role in the Fourth Industrial Revolution, and IT technology is expected to bring fundamental changes. This study focuses on the characteristics of blockchain technology and the effects of the intention to accept its technology in an empirical manner. The aspects of the technology are organized by researching blockchain technology and theories of technology acceptability and previous studies were used as guidelines to create the research model and propose the hypothesis. The research model is based on UTAUT with a set-up of 5 factors for performance expectancy and effort expectancy. For empirical analysis, a survey was conducted on 283 IT workers in Korea, To examine the hypothesis structural equation modeling was used performance expectancy was influenced by security, reliability, diversity, and economic efficiency while effort expectancy was influenced by reliability and economic efficiency. Performance expectancy, social influence, facilitating conditions affect the intention to accept. Innovativeness of an organization and control effects are influenced as well. The present study aims to provide practical guidance as supplementary research in utilizing blockchain technology, and the limitations of the study and future research possibilities are discussed as well.

• 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.