• Title, Summary, Keyword: Smart Contract

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Cost Minimization of Solidity Smart Contracts on Blockchain Systems

  • Lee, Wan Yeon
    • 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.

Design Model for Extensible Architecture of Smart Contract Vulnerability Detection Tool

  • Choi, Yun-seok;Lee, Wan Yeon
    • International Journal of Internet, Broadcasting and Communication
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    • v.12 no.3
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    • pp.189-195
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    • 2020
  • Smart contract, one of the applications of blockchain, is expected to be used in various industries. However, there is risks of damages caused by attacks on vulnerabilities in smart contract codes. Tool support is essential to detect vulnerabilities, and as new vulnerabilities emerge and smart contract implementation languages increase, the tools must have extensibility for them. We propose a design model for extensible architecture of smart contract vulnerability detection tools that detect vulnerabilities in smart contract source codes. The proposed model is composed of design pattern-based structures that provides extensibility to easily support extension of detecting modules for new vulnerabilities and other implementation languages of smart contract. In the model, detecting modules are composed of independent module, so modifying or adding of module do not affect other modules and the system structure.

Role Based Smart Contract For Data sharing

  • Joachim, Kweka Bruno;Rhee, Kyung-Hyune
    • Proceedings of the Korea Information Processing Society Conference
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    • pp.235-237
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    • 2018
  • The Internet has allowed many things to move fast, including sharing of data, files and others within a second. Many domains use applications range from IoT, smart cities, healthcare, and organizations to share the data when necessary. However, there are some challenges faced by existing systems that works on centralized nature. Such challenges are data breach, trustiness issue, unauthorized access and data fraud. Therefore in this work, we focus on using a smart contract which is used by blockchain platform and works on decentralized form. Furthermore, in this work our contract provides an access to the file uploaded onto the decentralized storage such as IPFS. By leveraging smart contract-role based which consist of a contract owner who can manage the users when access the certain resources such as a file and as well as use of decentralized storage to avoid single point of failure and censorship over secure communication channel. We checked the gas cost of the smart contract since most of contracts tends to be a high cost.

A Study on the Normative Recognition of Blockchain Smart Contract

  • Song, In-Bang;Kim, Yeon-Jong
    • 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.

Smart Contract and Dispute Resolution by Arbitration (스마트 계약과 중재에 의한 분쟁해결)

  • Han, Jong-Kyu
    • 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.

A Study on Privacy and Information Protection in Distributed Network Environment - Focused on Blockchain - (P2P 분산 네트워크 환경 내 프라이버시 및 정보보호 방안 - 블록체인 중심으로 -)

  • Park, Sumin;Hong, Seng-phil
    • Journal of Security Engineering
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    • v.14 no.2
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    • pp.167-180
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    • 2017
  • The smart contract of the block chain is a technology that guarantees the reliable contract without intermediary third party, and various studies are being carried out in various fields. When smart contracts are placed on the block chain, if the sensitive information of the contracting parties is registered, it may become an example of infringement of personal information. However, research on privacy and information protection among the research using the block chain smart contract seems to be insufficient. In this paper, we propose a design method to solve this issue by deriving the issue of reliable block chain smart contract and contribute to making it safe to use in P2P distributed network environment through case study.

The Smart Contract based Copyright Protection Model for Wisdom Contents Distribution (지혜콘텐츠 유통에 적합한 스마트계약 기반 저작권 보호 모델)

  • Yun, Sunghyun
    • Journal of The Korea Internet of Things Society
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    • v.5 no.2
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    • pp.21-26
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    • 2019
  • Wisdom contents is made by an ordinary person and contains life tips helpful in general. As the existing copyright management systems are designed for the corporate or professional authors, it's not easy to use and requires high cost for the ordinary person to get the copyright. Blockchain based system can notarize the block of transactions without help of trustful third party such as existing copyright protection center. Thus, blockchain based copyright protection model is needed to protect the ordinary author's copyright. In this study, we propose the smart contract based copyright protection model which run on the blockchain network. The proposed model consists of smart contract creation, contents purchase and profit sharing stages. The digital signature scheme is used to get the contract agreed by the seller and the author. The smart contract stores the author information, contents information and the percentage of the share as states. If the contents is sold, the sales tokens are redistributed to the author and the seller according to the share. The proposed model can be applied to the ordinary person's copyright registration and management for Wisdom contents distributed in cafe, blog, YouTube, etc.

A Study on the Design of Smart Contracts mechanism based on the Blockchain for anti-money laundering (자금 세탁 방지를 위한 블록체인 기반 스마트 컨트랙트 메커니즘 설계)

  • Kang, Heejung;Kim, Hye Ri;Hong, Seng-phil
    • Journal of Internet Computing and Services
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    • v.19 no.5
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    • pp.1-11
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    • 2018
  • The Blockchain is a technique that prevents data from being manipulated and guarantees the integrity and reliability of the data by all participants in the network jointly owning and validating the data. Since the Blockchain characterized by security, scalability and transparency, it is used in a variety of fields including logistics, distribution, IoT and healthcare, including remittance. In particular, there is a growing interest in smart contract that can create different forms of contracts and automate implementation based on Blockchain. Smart Contract can be used to pre-programme contracts and are implemented immediately when conditions are met. As a result, digital data can be more reliable. In this paper, we are conducting a study on the smart contract design as a way to solve such problems as illegal misuse of funds on virtual currency, which has become an issue recently. Through this process, we applied the customer identification and money laundering prevention process using smart contract, and then check the possibility of preventing money laundering and propose the ASM (AML SmartContract Mechant) design.

Smart Contract's Hierarchical Rules Modularization and Security Mechanism (스마트 컨트랙트의 계층형 규칙 모듈화와 보안 메커니즘)

  • An, Jung Hyun;Na, Sung Hyun;Park, Young B.
    • 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.

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A Static and Dynamic Design Technique of Smart Contract based on Block Chain (블록체인 기반의 스마트 컨트랙트 정적/동적 설계 기법)

  • Kim, Chul-Jin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.6
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    • pp.110-119
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    • 2018
  • Blockchain technology has been highly evaluated for its contracts (contracts for sale, real estate contracts) because of its excellent security, including integrity and non-repudiation. In a blockchain, these contract services can be developed using a technology called a smart contract, and several blockchain platforms provide a programming language for developing smart contracts. Bitcoin and Ethereum, typical blockchain platforms, provide the Bitcoin Scripts and Solidity languages. Using these programming languages, we can develop the smart contract, a digital contract that can be processed dynamically. Smart contracts are being developed in a variety of areas, but studies of designs based on a blockchain are insufficient. In this paper, we propose a meta-model and a static/dynamic design method based on Unified Modeling Language (UML) for smart contracts based on Ethereum. We propose a method for static design attributes and functions of smart contracts, and propose a technique for designing structures among contracts. Dynamic design proposes a technique for designing deployment, function calls, and synchronization among smart contracts, accounts, and blocks within a blockchain. Experiments verify the validity of the design method by applying the static/dynamic design method through real estate contracts.