• 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.

Survey on Smart Contract Programming Languages (스마트 컨트랙트 프로그래밍 언어 동향 조사)

  • Kim, Ik-Soon
    • 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.

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 Conference Key Distribution Scheme (스마트계약 기반 회의용 키 분배 기법)

  • Yun, Sunghyun
    • Journal of The Korea Internet of Things Society
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    • v.6 no.4
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    • pp.1-6
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    • 2020
  • Recently, epidemic of covid-19 causes rapid increase in demand for untact video conferences. In existing server-client based video conference systems such as Zoom, Google Meet, etc., the server generates the conference key and controls the access rights of meeting members and their contents with it. In this case, the server can fabricate or repudiate the meeting. So, the privacy of the meeting members is not guaranteed. It's necessary to make the conference key distribution scheme where all participants can verify the trustfulness without help of the server. The smart contract is the program stored to the blockchain. Its contents cannot be altered due to the property of the blockchain, and everybody can verify the execution results of it. In this study, we propose the smart contract based conference key distribution scheme. The proposed scheme is consisted of smart contract deployment, conference key generation and verification stages. The smart contract replaces the role of existing trustful server and the meeting members can generate the conference key according to the protocols implemented on it. The proposed scheme can be applied to the video conference systems and only the meeting members can access the conference key.

Design and Implementation of Ethereum Smart Contract State Monitoring System (이더리움 스마트 컨트랙트 상태 모니터링 시스템의 설계 및 구현)

  • Hong, Joongi;Kim, Suntae;Ryu, Duksan
    • Journal of Software Engineering Society
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    • v.28 no.2
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    • pp.1-6
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    • 2019
  • There are various stakeholders in the blockchain ecosystem. Since the emergence of Ethereum, many transactions have been made using smart contracts, and a wider range of stakeholders are participating, including not only developers, but also investors, banks, companies, and general users. However, various stakeholders have a problem in that it is difficult and complicated to check the state of smart contracts. If it becomes difficult to check the state, the reliability of the smart contract will be lowered and the utilization will be lowered. Also, if the state check is difficult and complicated for the developer, it will be difficult to provide high quality due to the difficulty of testing and debugging the smart contract developed by the developer. In this research, we propose a design and implementation method of the Ethereum Smart Contract State Monitoring System that enables various stakeholders and developers to easily and continuously check the state of smart contracts and analyze them using historical data.

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.