• Journal of Internet of Things and Convergence
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• v.6 no.4
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• pp.65-72
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• 2020

In this paper, we developed a web-based DApp system based on a private blockchain by applying machine learning techniques to automatically identify Android malicious apps that are continuously increasing rapidly. The optimal machine learning model that provides 96.2587% accuracy for Android malicious app identification was selected to the authorized experimental data, and automatic identification results for Android malicious apps were recorded/managed in the Hyperledger Fabric blockchain system. In addition, a web-based DApp system was developed so that users who have been granted the proper authority can use the blockchain system. Therefore, it is possible to further improve the security in the Android mobile app usage environment through the development of the machine learning-based Android malicious app identification block chain DApp system presented. In the future, it is expected to be able to develop enhanced security services that combine machine learning and blockchain for general-purpose data.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.05a
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• pp.182-185
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• 2019

최근 다양한 보안 사고들이 발생함에 따라 보안의 중요성이 대두되고 분야를 가리지 않고 일어나는 보안 이슈에 대응하기 위한 개발이 다양화되고 있다. 이 중 블록체인 기반 암호화폐의 일종인 이더리움(Ethereum)의 탈중앙화 어플리케이션(DApp) 시스템이 이슈화되었다. DApp을 이용하여 개발된 취약점 분산 관리 솔루션은 DApp의 기능과 장점을 포함한다. 취약점 분산관리 솔루션은 현 시대의 데이터 관리 구조의 문제점을 해결하기 위한 대책으로 제시되며 필요성을 드러낸다. 또한, 기존의 중앙 집중형 시스템에서 벗어나 솔루션의 이점을 활용하여 사용 영역을 확장할 수 있다.

• Journal of IKEEE
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• v.23 no.4
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• pp.1343-1352
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• 2019

To manage the Internet of Things(IoT) Network, which consists of a large number of various devices, a secure and automatic method of strengthening the IoT network is being proposed. Blockchain has a 'smart contract' element of autonomous execution method, which is emerging as a way to not only exchange data quickly without mediators but also securely and automatically manage processes between IoT devices. In this paper, we implement a prototype of the entire IoT device management system based on the EOSIO with DPoS(Distributed Proof of Stake)-based blockchain structure, proposed as a prior study, including the user application DApp(Decentralized Application) and the actual IoT devices (Raspberry Pi-based device, and smart lamp) that interact with the blockchain platform. We analyze the benefits of the system and measure the time overhead to show the feasibility of the system.

• Journal of the Korea Society of Computer and Information
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• v.24 no.2
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• pp.67-74
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• 2019

Since the announcement of bitcoin, new cryptocurrencies have been launched steadily and blockchain technology is also evolving with cryptocurrcies. In particular, security-related technologies such as consensus algorithm and hash algorithm have been improved and transaction processing speed has also been drastically improved to a level that can replace a centralized system. In addition, the advent of smart contract technology and the DApp platform also provides a means for cryptocurrency to decentralize social services beyond just payment. In this paper, we first describe the technologies for implementing cryptocurrency. And the major cryptocurrencies are described with a focus on the technical characteristics. In addition, the development of cryptocurrency technology is expanding the scope of use, so we tried to introduce various cryptocurrencies.

• Journal of Korea Game Society
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• v.21 no.2
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• pp.123-138
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• 2021

This study aims to empirically prove that blockchain games can provide business model innovations through interoperability among NFT based game items. Through our research on 'PlayDapp platform', we figured out that the technological innovation of blockchain games not only has provided a positive influence to the socio-economic and industrial ecosystem perspectives, but also it differentiates companies(game developers and platform providers in this eco-system) and increases customer benefits.

• Journal of the Korea Society of Computer and Information
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• v.26 no.2
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• pp.69-78
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• 2021

In this paper, we propose a implementation plan of the human resource pool recruitment system using private (permitted) blockchain. The term Human Resource has become commonly used and has come to recognize human resources as resources. Despite these changes, the use of human resource pools has been sluggish. Once entered, information is often not updated on a regular basis and does not provide sharing, searching, carrier management and anti-counterfeiting. In this research, in order to provide a human resource pool recruitment system that utilizes private (permitted) blockchain, we first used the blockchain network to enable sharing and searching of human resource pools, and to use keywords. Used to get results that meet certain conditions. Second, we added an institutional verification process to ensure the integrity of the input data and prepared preventive measures in the non-technical part by utilizing the structural characteristics of the blockchain to prevent counterfeiting and alteration. Third, we designed and implemented a Dapp (Decentralized application) that includes a Web UI so that each of the three groups can control the blockchain and the predefined processes and business logic.

• Journal of Digital Convergence
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• v.18 no.10
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• pp.253-263
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• 2020

Since the birth of the Ethereum in 2015, various decentralized applications (DApp) based on blockchain smart contract technology have appeared. However, CryptoKitty's case showed instability in terms of performance and scalability in real-world service environments. To solve this, a blockchain platform that developed a high transaction per second (TPS) has appeared, but there have been no environments and services to test it. Therefore, this paper intends to design and develop a game that can record the contents of all games on the chain and verify the performance and scalability of the blockchain platform through oversized transactions. The developed game generated a total of 6.3 million blocks and 8.9 million transactions through by 682 and verified the improved performance and scalability of the existing platform. Additionally, the maximum TPS was measured at 1,309 during the test period. In the future, it is expected that performance and scalability can be compared in a realistic environment through the method presented in this paper.

• Journal of Korea Multimedia Society
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• v.24 no.2
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• pp.255-266
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• 2021

Most common web or application system architectures have central network. As a result, central network can be supervised and controlled in all situation. And It has the advantage of easy to manage and fast to work. However, central network have a disadvantage of weak to security and unclear. In particular, many institutions used by web system be has many problems by central network. In this paper, we proposed blokchain technology based on ethereum to resolve of problem and trading structure that arise in cental network. We propose a decentralized application based on points including cryptocurrency functions and smart contract to the advantages of blockchain with a decentralized structure. The results of the performance experiment are as follows; It has shown the advantages of reliable use and security in a variety of environments(Windows, Ubuntu, Mac).

• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.31-40
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• 2021

Blockchain technology is also actively studied in the real estate transaction field, and real estate transactions have various ways. In this paper, we propose a model that simplifies the authentication procedure of auction systems using Ethereum's Ether to solve the problem of offline court auctions. The proposed model is written in Ethereum's Solidity language, the court registers the sale date and the sale date with the DApp browser, and the bidder accesses the address of the individual's wallet created through Metamask's private key. The bidder then selects the desired sale and enters the bid price amount to participate in the auction. The bidder's record of the highest bid price for the sale he wants is written on the Ethereum test network as a smart contract. and creates a block. Finally, smart contracts written on the network are distributed by the court auction manager to all nodes in the blockchain network, and each node in the blockchain network can be viewed and contract verified. As a result of analyzing the smart contracts of the proposed model and the performance of the system, there are fees incurred due to the creation and use of Ether on platforms using Ethereum, and participation. Ether's changes in value affect the price of the sale, resulting in inconsistent fees in smart contracts each time. However, in future work, we issue our own tokens to solve the market volatility problem and commission problem with the value change of Ether, and refine complex court auction systems.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.7
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• pp.283-290
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• 2022

Blockchain is a technology that secures integrity and transparency by distributing and storing transaction details within multiple node networks. Recently, research is being conducted to secure integrity by applying blockchain to Bill of Lading (B/L documents) of monetary value. In this paper, we study a blockchain-based bill of lading system to improve usability. The shippers register the issued bill of lading on the blockchain, and banks in each country read it to conduct L/C transactions. The consignees receive the goods after completing certification with a quick response code (QR) containing the bill of lading information. Through this, shippers enjoy merits in that they can shorten the time and cost of sending shipping documents by mail and prove the integrity of the documents. The consignees have the advantage of being able to check the documents at the same time as they are registered and trust the transaction. Finally, on the bank side, the security of shipping documents is ensured and verification can be done quickly.