• International journal of advanced smart convergence
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• v.9 no.2
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• pp.157-163
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• 2020

Recently the blockchain technology has been actively studied due to its great potentiality. The smart contract is a key mechanism of the blockchain system. Due to the short history of the smart contract, many issues have not been solved yet. One main issue is vulnerability and another main issue is cost optimization. While the vulnerability of smart contract has been actively studied, the cost optimization has been rarely studied. In this paper, we propose two cost optimization methods for smart contracts running on the blockchain system. Triggering a function in a smart contract program code may require costs and it is repeated continuously. So the minimization of costs required to trigger a function of smart contract while maintaining the performance equally is very important. The proposed two methods minimize the usage of expensive permanent variables deployed on the blockchain system. We apply the proposed two methods to three prevalent blockchain platforms: Ethereum, Klaytn and Tron. Evaluation experiments verify that the proposed scheme significantly reduces the costs of functions in the smart contract written with Solidity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.2
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• pp.286-293
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• 2021

Smart contract based on the blockchain technology can be applied to the real estate registry including transactions. The Ethereum coin using multi layered protocol is widely accepted as the token for the smart contract. Block chain smart contract using SOLIDITY or PYTHON can mediate transactions auch as sale or lease, creating various scenarios in the property market. Those smart contract can construct the basis for the blockchain real estate registry, which is expected to overcome conventional transaction costs concerning the national law system, the asymmetric information and the currency exchange. The advantages of blockchain technology, namely security, decentralization, global transparency and openness can be applied to the smart contract system on the property registry. Several countries have advanced such blockchain real estate registry project recently, but no actual implementation has been reported for years, owing to institutional and technological impasses.

• Journal of KIBIM
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• v.11 no.1
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• pp.1-10
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• 2021

Blockchain is a secure technology that enables transactions between parties without risking data corruption. Besides cryptocurrencies, blockchain technology is being widely adopted in various forms by diverse industries. One promising application is construction contracts. Given that construction projects are executed under strict contractual requirements, blockchain technology-based contracts can ensure that contractual requirements are executed among parties to the contract. The objective of this study is to apply blockchain technology to smart construction contracts and determine their potential feasibility in construction management. In this study, a prototype smart construction contract is presented and its applicability is explored. We conclude that smart construction contracts can be effective as a contractual tool to enhance payment flows in the construction process.

• 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.

• 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 the Semiconductor & Display Technology
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• v.18 no.1
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• pp.74-78
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• 2019

As software becomes larger and network technology develops, the management of distributed data becomes more popular. Therefore, it is becoming increasingly important to use blockchain technology that can guarantee the integrity of data in various fields by utilizing existing infrastructure. Blockchain is a distributed computing technology that ensures that servers participating in a network maintain and manage data according to specific agreement algorithms and rules to ensure integrity. As smart contracts are applied, not only passwords but also various services to be applied to the code. In order to reinforce existing research on smart contract applied to the blockchain, we proposed a dynamic conditional rule of smart contract that can formalize rules of smart contract by introducing ontology and SWRL and manage rules dynamically in various situations. In the previous research, there is a module that receives the upper rule in the blockchain network, and the rule layer is formed according to this module. However, for every transaction request, it is a lot of resources to check the top rule in a blockchain network, or to provide it to every blockchain network by a reputable organization every time the rule is updated. To solve this problem, we propose to separate the module responsible for the upper rule into an independent server. Since the module responsible for the above rules is separated into servers, the rules underlying the service may be transformed or attacked in the middleware. Therefore, the security mechanism using TLS and PKI is added as an agent in consideration of the security factor. In this way, the benefits of computing resource management and security can be achieved at the same time.

• Journal of Arbitration Studies
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• v.30 no.1
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• pp.87-111
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• 2020

Smart contracts are implemented by blockchain technology, which stores the terms of the contracts of both parties on the blockchain. In the event of an international dispute over smart contracts and blockchains, no special solution has been proposed, such as the enactment of the International Unification Act. The blockchain platform which operates smart contracts is decentralized and operates through distributed nodes around the world without central servers, making it difficult to establish jurisdiction and governing laws. As an alternative to traditional dispute-solving methods, a new mediation model-smart arbitration-is being attempted. The arbitration process is likely to be a preferred means of resolving disputes over smart contracts in practice. There are many problems, such as the fairness of the arbitration center on the selection and judgment of arbitrators, the question of securing reliability, the question of the validity of the arbitration agreement, and how much the court can be involved in the case. Preparations at the national level, such as fostering blockchains and smart contract experts, and overhauling the legal system, are needed.

• Journal of the Korea Society of Computer and Information
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• v.25 no.1
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• pp.187-198
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• 2020

In this paper, We purpose an improvement plan for the settlement of smart contracts into legal norms through the recognition of the norms of blockchain-based smart contracts and the main influence factors on the norms of smart contracts. First, in terms of the normative necessity of smart contracts, legal protection against technical errors, government-level public relations education, and basic laws governing smart contract business are needed. Second, the contract norms will be accepted by the contract norms based on the blockchain designed to make the responsible material clear in terms of smart contract usability. Third, in terms of regulation of smart contracts, it can be seen that smart contracts are subsumed from existing laws or considering new legislation, but the norm of smart contracts cannot be prioritized over ease of use.

• Journal of Advanced Navigation Technology
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• v.27 no.2
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• pp.235-246
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• 2023

In the rapid technological development of artificial intelligence (AI), electric vehicles, and robots based the fourth industrial revolution, semiconductors determine the core performance, and semiconductor competitiveness is directly related to national competitiveness. However, the Korean semiconductor industry has continuously weakened its competitiveness in the system semiconductor field, excluding memory semiconductors, so in this study, a new smart contract basedblockchain business model to engage the global market, which is the most urgent need for the growth of Korean fabless system semiconductor industry in recession. F-SBM (Fabless-Smart contract based Blockchain Model) proposed. In this study, through the new F-SBM, it was verified how to engage new customers for fabless firms through smart contract based consortium blockchain regarding technology, economy, and reliability items of fabless. This model has great significance in improving the high entry barriers to engaging new customers for the long-cherished desire of the Korean fabless system semiconductor industry and deriving new growth solutions.

• Korea Trade Review
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• v.48 no.3
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• pp.243-262
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• 2023

This study provides a systematic review of smart trade contracts, examining the research trends and theoretical background of utilizing smart contracts and blockchain technology for the digitalization and automation of trade contracts. Smart trade contracts are a concept that applies the automated contract system based on blockchain to trade-related transactions. The study analyzes the technical and legal challenges and proposes solutions. The technical aspect covers the development of smart contract platforms, scalability and performance improvements of blockchain networks, and security and privacy concerns. The legal aspect addresses the legal enforceability of smart contracts, automatic execution of contract conditions, and the responsibilities and obligations of contract parties. Smart trade contracts have been found to have applications in various industries such as international trade, supply chain management, finance, insurance, and energy, contributing to the ease of trade finance, efficiency of supply chains, and business model innovation. However, challenges remain in terms of legal regulations, interaction with existing legal frameworks, and technological aspects. Further research is needed, including empirical studies, business model innovation, resolution of legal issues, security and privacy considerations, standardization and collaboration, and user experience studies to address these challenges and explore additional aspects of smart trade contracts.