• Journal of the Korea Society of Computer and Information
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• v.26 no.2
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• pp.89-97
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• 2021

Blockchain is designed to collect and store the data recorded on the network in one block unit, and is connected and stored back and forth, and its form is similar to how the blocks are connected, so it is called a blockchain. Many companies are trying to popularize blockchain-based services at home and abroad, and blockchains are used in various industries. This study introduces the technical characteristics of the blockchain and deals with application services utilizing the blockchain. Introducing 5 types of blockchain architecture and core technologies and introducing blockchain application services that are used in payment services, blockchain service networks, blockchain real estate platforms, identity verification, cryptocurrency, diamond distribution path tracking, and blog information recording. do. It is expected to increase the understanding of the blockchain and provide usefulness in future blockchain research and service development.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.1-10
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• 2021

The purpose of the study is to contribute to the positive development of blockchain technology by providing data to examine security vulnerabilities and threats to blockchain-based services and review countermeasures. The findings of this study are as follows. Threats to the security of blockchain-based services can be classified into application security threats, smart contract security threats, and network (P2P) security threats. First, application security threats include wallet theft (e-wallet stealing), double spending (double payment attack), and cryptojacking (mining malware infection). Second, smart contract security threats are divided into reentrancy attacks, replay attacks, and balance increasing attacks. Third, network (P2P) security threats are divided into the 51% control attack, Sybil attack, balance attack, eclipse attack (spread false information attack), selfish mining (selfish mining monopoly), block withholding attack, DDoS attack (distributed service denial attack) and DNS/BGP hijacks. Through this study, it is possible to discuss the future plans of the blockchain technology-based ecosystem through understanding the functional characteristics of transparency or some privacy that can be obtained within the blockchain. It also supports effective coping with various security threats.

• Journal of Information Processing Systems
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• v.16 no.4
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• pp.935-958
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• 2020

The core value of finance is credit. It can be said that without credit, there can be no finance. The distributed structure of the blockchain and the low-cost trust-building mechanism based on mathematical algorithms provide a new solution and path for solving and optimizing related problems in the financial field. The blockchain technology is applied in the development of the financial industry through consensus mechanisms, smart contracts, and distributed networks. In this research, a comprehensive survey of the blockchain technology is proposed in the development of financial services including equity crowdfunding and credit investigations in inclusive finance, cross-border remittance, Internet financial payment, P2P lending, supply chains finance, and the application of blockchain in the field of anti-money laundering. This paper discusses the role of blockchain in solutions to different issues in the financial field. It also discusses the architectures in different financial service application scenarios from the perspective of the financial trust mechanism and the perspective of the technology and rule change of blockchain participation in financial innovation. Finally, the problems and challenges of blockchain in financial services are discussed, and corresponding solutions are proposed.

• Journal of the Korea Society of Computer and Information
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• v.25 no.10
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• pp.77-86
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• 2020

In this paper, we propose a technique for blockchain service replication and recovery using kubernetes(BR2K) that robustly executes blockchain services based on replication and supports systematic recovery in case of the service failure. Blockchain services are being developed and applied in various fields such as administration, finance, and medical systems based on the features of blockchain, such as decentralization, high security, and data integrity. In such areas where service continuity is important, it is necessary to provide robustness for execution of blockchain services, and a recovery plan for service failure is also required. To this end, BR2K provides an execution replication technique that systematically supports the sustainable execution of blockchain application services. Also, it introduces a robust container registry based on the blockchain service registry, systematically supporting the recovery of service failures by using it. In addition, Truffle, a blockchain service development framework, is extended to utilize the Kubernetes container management tool, and BR2K provides a technique for rapidly deploying blockchain services using the extended framwork.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.5
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• pp.899-914
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• 2022

A blockchain-based decentralized service can offer reliable services without the centralized server by operating the system based on the consensus among byzantine participants. Participants can interact with the blockchain network through a digital signature mechanism but the private key management issue remains unresolved. NIST SP800-57 provides a key-management guidance but this guidance is not appropriate for blockchain-based services because it does not consider a decentralized environment. In this paper, we define the core functions of the blockchain wallet application for private key management and present security protections according to NIST SP800-57, as well as related techniques to satisfy them. Finally, we propose the private key management guideline for secure blockchain-based decentralized services.

• International Journal of Computer Science & Network Security
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• v.23 no.9
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• pp.29-36
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• 2023

Blockchain is an emerging technology that is used to address ownership, centrality, and security issues in different fields. The blockchain technology has converted centralized applications into decentralized and distributed ones. In existing sharing economy applications, there are issues related to low efficiency and high complexity of services. However, blockchain technology can be adopted to overcome these issues by effectively opening up secure information channels of the sharing economy industry and other related parties, encouraging industry integration and improving the ability of sharing economy organizations to readily gain required information. This paper discusses blockchain technology to enhance the development of insurance services by proposing a five-layer decentralized model. The Najm for Insurance Services Company in Saudi Arabia was employed in a case study for applying the proposed model to effectively solve the issue of online underwriting, and to securely and efficiently enhance the verification and validation of transactions. The paper concludes with a review of the lessons learned and provides suggestions for blockchain application development process.

• Journal of the Korea Society of Computer and Information
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• v.25 no.3
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• pp.73-80
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• 2020

In this paper, we propose a robust execution scheme for Ethereum blockchain application services which provide continuous services and support recovery even in the case of failures of those services. As of now, blockchain services are rapidly expanding to all industries and being combined with various infrastructure services of public institutions. But if these services fail in disastrous situations such as earthquakes, floods and terrors or various hacking attacks, the aftermath is very serious and its side effects are difficult to assess. To resolve this issue, we develop the service registry as a smart contract of the Ethereum blockchain, which provides useful information on the services to users even in disasters. With the help of the service registry, we also present a method of replicating services on the basis of the ETCD distributed storage system. The proposed scheme is confirmed by the test service developed by the proposed techniques.

• Journal of the Korea Society of Computer and Information
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• v.26 no.4
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• pp.75-84
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• 2021

In this paper, we introduce InfoDID, a robust user information management service based on DID that manages user information reliably. Since blockchain technology provides an environment in which data can be handled transparently on a decentralized basis, various services using blockchain are currently being developed As the importance of user's personal information has recently emerged, the DID technology is receiving attention. The technology allows a user to control his or her information through decentralized identifiers, and various information management services are being tried based on the technology. Using blockchain-based DID technology, InfoDID reliably controls personal information requested frequently, helping users to provide their information to other services more conveniently. In addition, to support service continuity, InfoDID uses BR2K technique that provides robust execution of blockchain application services, so that even partial service failures can be systematically recovered. To facilitate this operation, we present a replication status monitoring tool that can continuously check the replication states of blockchain application services running in association with the BR2K technique such as InfoDID.

• International Journal of Advanced Culture Technology
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• v.10 no.2
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• pp.233-239
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• 2022

Recently, research is being conducted on the rapid service provision and reliability of the instance-based rather than the existing IP-based structure. Research is mainly conducted through Block cloud, a platform that combines service-centric networking (SCN) and blockchain. In addition, the Internet of Things network has been proposed as a fog computing environment in the structure of the existing cloud computing. Fog computing is an environment suitable for real-time information processing. In this paper, we propose a new Internet network structure based on fog computing that requires real-time for rapid processing of IoT services. The proposed system applies IoTA, the third-generation blockchain based on DAG, to the block cloud. In addition, we want to propose a basic model of the object block chain and check the application services of electric vehicles.

• 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.