• Title, Summary, Keyword: Smart Contract

Search Result 110, Processing Time 0.031 seconds

Private Blockchain and Smart Contract Based High Trustiness Crowdsensing Incentive Mechanism (프라이빗 블록체인 및 스마트 컨트랙트 기반 고신뢰도 크라우드센싱 보상 메커니즘)

  • Yun, Jun-hyeok;Kim, Mi-hui
    • Journal of the Korea Institute of Information Security & Cryptology
    • /
    • v.28 no.4
    • /
    • pp.999-1007
    • /
    • 2018
  • To implement crowdsensing system in reality, trustiness between service provider server and user is necessary. Service provider server could manipulate the evaluation of sensing data to reduce incentive. Moreover, user could send a fake sensing data to get unjust incentive. In this paper, we adopt private blockchain on crowdsensing system, and thus paid incentives and sent data are unmodifiablely recorded. It makes server and users act as watcher of each others. Through adopting smart contract, our system automates sensing data evaluation and opens to users how it works. Finally, we show the feasibility of proposing system with performance evaluation and comparison with other systems.

Blockchain Oracle for Random Number Generator using Irregular Big Data (비정형 빅데이터를 이용한 난수생성용 블록체인 오라클)

  • Jung, Seung Wook
    • Convergence Security Journal
    • /
    • v.20 no.2
    • /
    • pp.69-76
    • /
    • 2020
  • Blockchain 2.0 supports programmable smart contract for the various distributed application. However, the environment of running smart contract is limited in the blockchain, so the smart contract only get the deterministic information, such as block height, block hash, and so on. Therefore, some applications, which requires random information, such as lottery or batting, should use oracle service that supply the information outside of blockchain. This paper develops a random number generator oracle service. The random number generator oracle service use irregular big data as entropy source. This paper tests the randomness of bits sequence generated from oracle service using NIST SP800-22. This paper also describes the advantages of irregular big data in our model in perspective of cost comparing hardware entropy source.

A Study on Smart Contract for Personal Information Protection (개인정보보호를 위한 스마트컨트랙트 연구)

  • Kim, Young-Hun
    • Journal of Digital Convergence
    • /
    • v.17 no.3
    • /
    • pp.215-220
    • /
    • 2019
  • The block chain technology is a technique that prevents manipulation of data and ensures integrity and reliability. Ethereum is building a smart contract environment as a type of encryptionenabled system based on block chains. Smart contracts can be implemented when conditions are met, thus increasing confidence in digital data. However, smart contracts that are being tried in various ways are not covered by information security and personal information protection. The structure in which the network participant can view the open transaction ledger is exposed to data or personal information listed in the block chain. In this study, it is possible to manage the data of personal information recorded in the block chain directly. This study is protected personal information by preventing the exposure of personal information and by executing time code, it is possible to erase recorded information after a certain period of time has elapsed. Based on the proposed system in the future, it is necessary to study the additional management techniques of unknown code defects or personal information protection.

Accident Information Based Reliability Estimation Model for Car Insurance Smart Contract (자동차보험용 스마트 컨트랙트를 위한 사고정보 기반 신뢰도 산정 모델)

  • Lee, Soojin;Kim, Aeyoung;Seo, Seung-Hyun
    • KIPS Transactions on Computer and Communication Systems
    • /
    • v.9 no.4
    • /
    • pp.89-100
    • /
    • 2020
  • In order to reduce the time and cost used in insurance processing, studies have been actively carried out to apply blockchain smart contract technology to car insurance. However, by using traffic data that is insufficient to prove accidents, existing studies are being exposed to the risk of insurance fraud, such as forgery and overstated damage by malicious insurers. To solve this problem, we propose an accident data-based reliability estimation model by using both various types of data through sensors, RSUs, and IoT devices embedded in automobiles and smart contracts. In particular, the regression model was applied in consideration of the weight estimation according to the type of traffic accident data and the reliability estimation model trained according to various accident situations. The proposed model is expected to effectively reduce fraud and insurance litigation while providing transparency in the insurance process and streamlining it is well.

A Study on the Measurement Method of Cold Chain Service Quality Using Smart Contract of Blockchain (블록체인의 스마트계약을 이용한 콜드체인 서비스 품질 측정 방안에 대한 연구)

  • Kim, ChangHyun;Shin, KwangSup
    • The Journal of Society for e-Business Studies
    • /
    • v.24 no.3
    • /
    • pp.1-18
    • /
    • 2019
  • Due to the great advances in e-Marketplace and changes in type of items purchased from the online market, it has been dramatically increased the demand of the storage and transportation under the special conditions such as restricted temperature. Especially, the cold chain needs the way to transparently measure and monitor the entire network in realtime because it has a very complicated structure and requires totally different criteria at the every different steps and items. In this research, it has been presented the performance evaluation metrics to make contract using service level agreement (SLA), the way to apply the smart contract based on blockchain, the structure of blocks, service platform and application in order to build cold chain which can prevent the risk factors by measuring and sharing information in realtime using block chain technology. In addition, we have proposed the way to store the measured performance and reputation of each player in the block using smart contract based on SLA. With the presented framework, all players including service providers as well as users can secure the information for making the rational decisions. When the service platform is actually built and operated, it seems possible to secure the information in transparently and realtime. Also, it is possible to prevent the risk factors or prepare the preemptive plans to react on them.

Smart Contract Code Rewritter for Improving Safety of Function Calls (함수 호출의 안전성 향상을 돕는 스마트 계약 코드 재작성기)

  • Lee, Sooyeon;Jung, Hyungkun;Cho, Eun-Sun
    • Journal of the Korea Institute of Information Security & Cryptology
    • /
    • v.29 no.1
    • /
    • pp.67-75
    • /
    • 2019
  • When a Solidity smart contract has a problem in calling a function of another contract, the fallback function is supposed to be executed automatically. However, it may be are arbitrarily created, with their behaviors unknown to developers, and fallback function execution is vulnerable to exploits by attackers. in In this paper, we propose a preprocessing based method to reduce the risk with less overhead of developers'. Developers mark the intention using the newly defined keywords in this paper, and the preprocessor reduces the risk by preprocessing the conditional variables and conditional statements according to the keywords.

A Study on Privilege Elevation Attack Management for Smart Transaction Security on BlockChain Etherium Based System

  • Min, Youn-A
    • Journal of the Korea Society of Computer and Information
    • /
    • v.24 no.4
    • /
    • pp.65-71
    • /
    • 2019
  • IAs smart device penetration rate is more than 90%, mobile transaction ratio using smart device is increasing. Smart contracts are used in various areas of real life including smart trading. By applying smart contracts to the platform for smart transactions through block-chain technology, the threat of hacking or forgery can be reduced. However, various threats to devices in smart transactions can pose a threat to the use of block chain Etherium, an important element in privilege and personal information management. Smart contract used in block chain Ethereum includes important information or transaction details of users. Therefore, in case of an attack of privilege elevation, it is very likely to exploit transaction details or forge or tamper with personal information inquiry. In this paper, we propose a detection and countermeasure method for privilege escalation attack, which is especially important for block chain for secure smart transaction using block chain Ethereum. When comparing the results of this study with the results of similar applications and researches, we showed about 12~13% improvement in performance and suggested the future countermeasures through packet analysis.

A Survey of Cryptocurrencies based on Blockchain

  • Kim, Junsang
    • Journal of the Korea Society of Computer and Information
    • /
    • v.24 no.2
    • /
    • pp.67-74
    • /
    • 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.

Improved Ad Hoc On-demand Distance Vector Routing(AODV) Protocol Based on Blockchain Node Detection in Ad Hoc Networks

  • Yan, Shuailing;Chung, Yeongjee
    • International Journal of Internet, Broadcasting and Communication
    • /
    • v.12 no.3
    • /
    • pp.46-55
    • /
    • 2020
  • Ad Hoc network is a special wireless network, mainly because the nodes are no control center, the topology is flexible, and the networking could be established quickly, which results the transmission stability is lower than other types of networks. In order to guarantee the transmission of data packets in the network effectively, an improved Queue Ad Hoc On-demand Distance Vector Routing protocol (Q-AODV) for node detection by using blockchain technology is proposed. In the route search process. Firstly, according to the node's daily communication record the cluster is formed by the source node using the smart contract and gradually extends to the path detection. Then the best optional path nodes are chained in the form of Merkle tree. Finally, the best path is chosen on the blockchain. Simulation experiments show that the stability of Q-AODV protocol is higher than the AODV protocol or the Dynamic Source Routing (DSR) protocol.