• Journal of Internet of Things and Convergence
• /
• v.5 no.2
• /
• pp.67-72
• /
• 2019

As Internet voting can take place regardless of a voter's location, the participation rate of the voters would be increased and economic costs will be reduced. But the drawback of it is that all participants have to trust the election management server. If the server colludes with the specific candidate, the other candidates cannot prove rigged election. In addition, majority of researches on Internet voting are mainly focused on the voting restricted by the region and the country. Thus, it's not appropriate for the election in Internet community such as YouTube channels. As the Internet community is composed of members from all around the world, the new type of voting model is needed. In this study, we propose the smart contract based Internet voting model applicable on the blockchain network. The proposed smart contract model consists of candidate registration, voter registration, voting and counting stages. In the proposed model, anonymity of the voter is assured in the voter registration and voting stages, and all candidates can confirm the fairness of the election in the counting stage.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2019.05a
• /
• pp.290-292
• /
• 2019

Since the advent of blockchain and bitcoin, decentralization has been accelerating around the world as a public blockchain ethereum with smartcontract has begun. Developers can use Ethereum's blockchain development platform to develop "distributed applications" (DApp) running on a decentralized P2P network, and various types of devices from IoT to mobile can participate in a block-chain distributed environment have. Using Ethereum's blockchain development platform, developers can develop "Decentralized Application (DApp)" that run on a decentralized P2P network and various types of devices from IOT to mobile can participate in distributed blockchain environments. There are many ways to interact with the blockchain and the smart contract, but users tend to prefer the mobile methods due to their convenience and accessibility advantages. Therefore, the author developed an Android based voting DApp and researched related issues. Since the current development methods of DApp are not adequately researched and standardized, efficient methods for developing user-friendly DApp were studied. Because DApp has to spend a certain amount of fees to interact with blockchain, it has intensively investigated the gas problem of Smart Contract code and the security problem of code, and author would like to introduce it in this paper.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.24 no.6
• /
• pp.786-794
• /
• 2020

For systematic pet management, the pet registration system has established. It makes the owner of the pet is given greater responsibility through the pet registration system but it also provided with welfare. One of the advantages of the pet registration system is that prepare system what return to owner quickly and safety through information inquiry when the pets are lost. But there are some conflict with the law in the information inquiry, so it occurs interfere the system. In this paper, we propose using the Smart Contract to finding the missing animal effectively. Proposed method discloses only the partially information. Thus it will be eliminated conflict parts, and increases the information accessibility to increase the number of people who can inquiry information. In addition, keeping the RFID inquired feature for compatible with the existing system. The smart contract querying enables quickly and precision access to information. Lastly, compare the proposed method with existing method to see the improvement.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.17 no.11
• /
• pp.3003-3029
• /
• 2023

The rapid evolution of the IoT has paved the way for new opportunities in smart city domains, including e-health, smart homes, and precision agriculture. However, this proliferation of services demands effective SLAs between customers and service providers, especially for critical services. Difficulties arise in maintaining the integrity of such agreements, especially in vulnerable wireless environments. This study proposes a novel SLA management model that uses an SDN-Enabled WSN consisting of wireless nodes to interact with smart contracts in a straightforward manner. The proposed model ensures the persistence of network metrics and SLA provisions through smart contracts, eliminating the need for intermediaries to audit payment and compensation procedures. The reliability and verifiability of the data prevents doubts from the contracting parties. To meet the high-performance requirements of the blockchain in the proposed model, low-cost algorithms have been developed for implementing blockchain technology in wireless sensor networks with low-energy and low-capacity nodes. Furthermore, a cryptographic signature control code is generated by wireless nodes using the in-memory private key and the dynamic random key from the smart contract at runtime to prevent tampering with data transmitted over the network. This control code enables the verification of end-to-end data signatures. The efficient generation of dynamic keys at runtime is ensured by the flexible and high-performance infrastructure of the SDN architecture.

• KIPS Transactions on Software and Data Engineering
• /
• v.11 no.10
• /
• pp.399-408
• /
• 2022

ERC-20, the standard API for Ethereum token smart contracts, was introduced to ensure compatibility among applications such as wallets and decentralized exchanges. However, many compatibility vulnerability problems have existed because there is no rigorous functional specifications for each API nor conformance review tools for the standard. In this paper, we proposed a new review procedure and a tool to perform the procedure to review if ERC-20 token smart contract programs for the Ethereum blockchain conform to the de facto standards. Based on the knowledge from an analysis on the ERC-20 API functional behavior of the top 100 token smart contract programs in the existing Ethereum blockchain, a new specification for the de facto standard for ERC-20 API was explicitly defined. The new specification enabled us to design a systematic review method for Ethereum smart contract programs. We developed a tool to support this review method and we evaluated a few benchmark programs with the tool.

• 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.

• 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.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.17 no.1
• /
• pp.193-200
• /
• 2022

In this study, the intellectual property rights of digital contents (creations) are protected by using block chain technology that cannot be damaged or forged. So, we build a blockchain-based content sales revenue tracking system and platform that activates the transaction and distribution of digital content (creation). We developed an API server that can be used for content registration and revision history management smart contract, license management smart contract according to content purchase, content inquiry function through files and hashes, and web and APP services. Through this, it is possible to prove the relationship between the rights of the creators of digital content creations and protect the rights of the creators.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.22 no.4
• /
• pp.195-201
• /
• 2022

For a efficient distance education environment, the need for correct problem recommendation guides considering the learner's exact learning pattern is increasing. In this paper, we study block chain based smart contract technology to suggest a method for presenting the optimal problem recommendation path for individual learners based on the data given by situational weights to the problem patterns of learners collected in the distance education environment. For the performance evaluation of this study, the learning satisfaction with the existing similar learning environment, the usefulness of the problem recommendation guide, and the learner data processing speed were analyzed. Through this study, it was confirmed that the learning satisfaction improved by more than 15% and the learning data processing speed was improved by more than 20% compared to the existing learning environment.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
• /
• v.9 no.9
• /
• pp.819-831
• /
• 2019

The types of properties traded in modern times are rapidly increasing due to changes in consumption patterns. However, as the type of properties traded increases, estimation about the value of properties may become inaccurate. There is a problem that it is difficult for consumers to estimate the right value and the variety of trading forms makes it difficult to guarantee the reliability of value estimation As access to a variety of properties has expanded, these shortcomings are considered to be a factor that hinders the stability of the shared economic market. In this paper, to resolve this issue, we present a blockchain-based property contract service through a trusted broker. The developed service registers trusted brokers into smart contracts on the Ethereum blockchain and use them for the evaluation and contract process of properties. In addition, registered contents, proposals and contracts of properties are stored in the blockchain to ensure the reliability of the contract process. Every step of the contract process is stored in the smart contract, recorded in the transaction history of the blockchain, ensuring the reliability of the stored data. In addition, the entire process of registration, proposal, and contract is driven by smart contracts designed by state machine technology, enabling users to more securely control the contract process.