• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.571-572
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• 2017

The blockchain technology that implements electronic money uses decentralized computing and all transactions in a blockchain are open to everyone. This technique seems to guarantee anonymity by performing the transaction on the address instead of the user, but by using direction acyclic graph based on the transaction graph, the privacy problem is caused by tracking the addresses. In this paper, we analyze various techniques for centralized processing which makes it difficult to find the relevance on the graph in order to protect the privacy in the block chain technology. We also analyze the techniques of anonymizing in a distributed way to enhance privacy. Using the zero knowledge proof scheme guarantees full distributed anonymity but requires more computation and storage space, and various techniques to make this efficient are proposed. In this paper, we propose a privacy protection scheme of blockchain technology to integrate existing privacy protection techniques into a blockchain technology and perform it more efficiently with a centralized or decentralized technique.

• Journal of Industrial Convergence
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• v.20 no.9
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• pp.47-58
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• 2022

Digital content is difficult to distinguish between the original and the replica due to its nature. For this reason, NFT technology using blockchain technology is attracting attention because it can guarantee the proof and scarcity of the original digital content. However, the NFT buyer does not own the copyright to the digital content, but the ownership. In particular, since the minting process of issuing NFTs is possible for anyone, there is a copyright threat to the copyright holder. In this study, we propose a verification protocol based on DID for the process of issuing and transacting NFTs for copyright protection of copyright holders' digital contents. As a research method, the problems of research cases related to digital contents were analyzed and the safety was comparatively analyzed. NFT issuance can only be issued by copyright holders whose identity has been verified through DID, and only users who have completed authentication can participate in the transaction to prevent indiscriminate theft and use of digital content and form a safe and transparent transaction market.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.71
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• pp.217-243
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• 2016

As the rapid development of IT and the internet changed the trading method from the traditional offline transaction into the online e-Trading, the international documentation standards, the eUCP and the domestic laws and legislations have been established, adapting to the new e-Trading environment. This study was conducted to analyze the factors which affect the use of uTradeHub on the domestic trading companies and trade-related organizations and suggest how to activate e-Trading. To do this, classify the users into the enterprises and the trade-related organizations, set up the hypothesis of the study with the measurement variables of the user convenience, the new service, the system suitability and the legislation environment and carry out a survey targeting the trading companies and the trade-related offices to do an actual proof analysis. The analysis was performed by using the statistical program, SPSS IBM22.0, and the study hypothesis was tested by the multiple regression analysis methodology. The test result showed that the trading companies set a high value on the user convenience, the new service and the legislation environment of uTradeHub, meanwhile the trade-related organizations regarded the system security and reliability, the user convenience and the legislation environment as the major affecting factor on the use of uTradeHub.

• International Commerce and Information Review
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• v.12 no.1
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• pp.35-54
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• 2010

This article explored the bank's responsibilities in electronic payment system between Korea and U.S.A. In order to complete my research object, I used Article 4A of the U.C.C. and EFTA of 1978 and by Electronic Financial Transaction Act of Korea as a analytic instruments. I also adapted America's various regulations to regulate concerned parties(banks). The system of this article is going to display as fellows; First, I presented recent trend and legal stabilities of electronic payment in this article. Second, I focuses on the allocation of risk of loss caused by ambiguous term in payment orders that do not express the subjective intention of the senders. I also did analyze the solution procession of error occurring in course of send of payment order. Third, In any action which involves a customers's liability for an unauthorized electronic fund transfer, the burden of proof is upon the financial institution to show that the electronic fund transfer was authorized. Forth, Customers have to report the error and unauthorized electronic fund transfer after awaring of it. Then bank will be liable for such a unauthorized electronic fund transfer. But If customer's failure to report, the bank has exemptions. Lastly, In order to prevent or detect the unauthorized electronic fund transfer, bank will agree with custom to establish a commercially reasonable security procedure, while bank has duties to notify in order to decrease the loss resulted from unauthorized payment order in korea law.

• Current Optics and Photonics
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• v.6 no.5
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• pp.453-462
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• 2022

Blockchain technology provides a decentralized and peer-to-peer network, which has the advantages of transparency and immutability. In this paper, a novel secure authentication scheme applying digital holography to blockchain technology is proposed to protect privacy information in network nodes. The transactional information of the node is chained permanently and immutably in the blockchain to ensure network security. By designing a novel two-dimensional (2D) array data structure of the block, a proof of work (PoW) in the blockchain is executed through digital holography technology to verify true authentication and legal block linkage. A hash generated from the proposed algorithm reveals a random number of 2D array data. The real identity of each node in the network cannot be forged by a hacker's tampering because the privacy information of the node is encrypted using digital holography and stored in the blockchain. The reliability and feasibility of the proposed scheme are analyzed with the help of the research results, which evaluate the effectiveness of the proposed method. Forgery by a malicious node is impossible with the proposed method by rejecting a tampered transaction. The principal application is a secure anonymity system guaranteeing privacy information protection for handling of large information.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.1
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• pp.1-9
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• 2022

The PoN (Proof of Nonce) distributed consensus algorithm basically uses a non-competitive consensus method that can guarantee an equal opportunity for all nodes to participate in the block generation process, and this method was expected to resolve the first trilemma of the blockchain, called the decentralization problem. However, the decentralization performance of the PoN distributed consensus algorithm can be greatly affected by the network transaction transmission delay characteristics of the nodes composing the block chain system. In particular, in the consensus process, differences in network node performance may significantly affect the composition of the congress and committee on a first-come, first-served basis. Therefore, in this paper, we presented a problem by analyzing the decentralization performance of the PoN distributed consensus algorithm, and suggested a fairness control algorithm using a learning-based probabilistic acceptance rule to improve it. In addition, we verified the superiority of the proposed algorithm by conducting a numerical experiment, while considering the block chain systems composed of various heterogeneous characteristic systems with different network transmission delay.

• The Korean Journal of Archival Studies
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• no.73
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• pp.47-79
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• 2022

NFT is literally a 'non-fungible token', a digital file that records specific virtual assets on a blockchain. Events such as ownership of the asset and transaction history are recorded on the blockchain through the token transaction, so counterfeiting and falsification are impossible. Therefore, NFT is used as a tool that can uniquely represent a specific virtual asset. The main purpose of this paper is to examine the characteristics of NFT from a records management point of view and to find ways to use them, and focuses on digital records that have the characteristics of assets as digital works. For this purpose, we first examine the basic concept of NFT and the principle of ownership and proof of value as an asset for digital works. In addition, it was confirmed how the advantages of NFT were applied through NFT use cases in various fields, and in particular, areas related to audio-visual records such as art, music, sports, and fashion were focused on. Furthermore, by comparing the characteristics of digital records with those of NFT, factors applicable to electronic records were identified. Finally, the types of digital records that are expected to be effective in the application of NFT were identified, and the possibility of their use and discussion points for introduction in records management are presented.

• Journal of Korean Society of Archives and Records Management
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• v.20 no.4
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• pp.81-105
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• 2020

This study examines the possibility of applying various recordkeeping methods through a platform built in 2019 by the National Archives of Korea. In particular, it aims to develop a way to track and store transactions using blockchain and to design and present the method of records management automation using smart contracts. In this regard, a literature review, a system analysis of CAMS and MAM, interviews with the experts, designing, implementation, and the development of the system's proof of concept were performed. These efforts resulted in the proposal of an archives and records management strategy utilizing blockchain, which guarantees transparency and accountability by preserving an audit trail on recordkeeping activities.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.1
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• pp.225-234
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• 2019

Bitcoin is a cryptocurrency with characteristics such as de-centralization and distributed ledger, and these features are maintained through a mining system called "proof of work". In the mining system, mining difficulty is adjusted to keep the block generation time constant. However, Bitcoin's current method to update mining difficulty does not reflect the future hash power, so the block generation time can not be kept constant and the error occurs between designed time and real time. This increases the inconsistency between block generation and real world and causes problems such as not meeting deadlines of transaction and exposing the vulnerability to coin-hopping attack. Previous studies to keep the block generation time constant still have the error. In this paper, we propose a machine-learning based method to reduce the error. By training with the previous hash power, we predict the future hash power and adjust the mining difficulty. Our experimental result shows that the error rate can be reduced by about 36% compared with the current method.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.4
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• pp.168-177
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• 2020

In recent years, importance of blockchain systems has been grown after success of bitcoin. Distributed consensus algorithm is used to achieve an agreement, which means the same information is recorded in all nodes participating in blockchain network. Various algorithms were suggested to resolve blockchain trilemma, which refers conflict between decentralization, scalability, security. An algorithm based on Byzantine Agreement among Decentralized Agents (BADA) were designed for the same manner, and it used limited committee that enables an efficient consensus among considerable number of nodes. In addition, election of committee based on Proof-of-Nonce guarantees decentralization and security. In spite of such prominence, application of BADA in actual blockchain system requires further researches about performance and essential features affecting on the performance. However, performance assessment committed in real systems takes a long time and costs a great deal of budget. Based on this motivation, we designed and implemented a simulator for measuring performance of BADA. Specifically, we defined a simulation framework including three components named simulator Command Line Interface, transaction generator, BADA nodes. Furthermore, we carried out response surface analysis for revealing latent relationship between performance measure and design parameters. By using obtained response surface models, we could find an optimal configuration of design parameters for achieving a given desirable performance level.