• Journal of the Korea Convergence Society
• /
• v.9 no.9
• /
• pp.83-88
• /
• 2018

The blockchain is the technique which is used in decentralized system instead of centralized system. Its characteristics are anonymous and transparency. However, there are still some traditional attacks. In this paper, we introduced some of the famous consensus algorithm with blockchain: Bitcoin, Algorand, and IOTA. Also, this paper talked about how each consensus algorithm tried to solve those traditional attacks such as double spending attack or sybil attack. Furthermore, if the consensus algorithm does not consider those attacks yet, then the author would introduce additional methods to solve those attacks. Furthermore, this paper proposed the new scenario that can make classical attacks be happened.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2020.05a
• /
• pp.242-245
• /
• 2020

최근 IT 기술의 발전에 따라 블록체인 기술과 융합하려는 다양한 시도를 보인다. 비트코인(Bitcoin)의 탄생으로 알려지게 된 블록체인은 P2P (Peer-to-Peer) 네트워크에서 데이터의 무결성 조건을 만족할 수 있게 되면서 보안 기술에 대해 많은 연구가 진행 중이다. 데이터의 무결성을 증명하기 위해 합의 알고리즘을 사용하는데 합의 알고리즘의 처리속도 및 저장 공간 문제 등으로 인해 다른 분야로 확장에 어려움을 겪고 있다. 따라서 블록체인을 구성하는 환경이나 목표에 따라서 적절한 합의 알고리즘을 선택하는 것이 중요하다. 본 논문에서는 확장성 문제를 해결할 수 있는 Bitcoin-NG 합의 알고리즘을 비롯하여 다양한 합의 알고리즘의 원리와 장단점을 소개한다. 블록의 합의에 참여하는 범위, 리더를 선정하는 방법 등의 기준으로 Bitcoin-NG 알고리즘이 확장성 문제에 긍정적인 합의 알고리즘으로서 갖춘 특징을 살펴 보고 앞으로 합의 알고리즘의 발전 방향에 대해 고찰한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.23 no.6
• /
• pp.21-26
• /
• 2023

Recently, cryptocurrencies such as Ethereum and Bitcoin, which are called digital assets, Cryptocurrency has completely different characteristics from real assets and must be handled carefully and safely. But The disadvantage of digital assets is that anyone who knows the private key of the wallet can easily steal the digital assets. If the seed card is lost, stolen, or exposed when used, you can use the wallet by recovering the private key using the seed card acquired by someone else. In this paper We aim to safely protect encrypted assets by using QR codes when providing mnemonic words needed to create seed cards.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2024.01a
• /
• pp.331-334
• /
• 2024

하이퍼레저 패브릭(Hyperledger Fabric)은 참여자의 신원을 확인하고, 정보교환(트랜잭션)의 유효성을 검증하는 허가형 블록체인 모델이다. 기존의 대표적인 블록체인 모델인 비트코인, 이더리움과 대비하여 효율적인 데이터 검증 방안이 가능한대, 체인코드와 채널, 그리고 피어를 중심으로 구성되어 있기 때문이다. 먼저 본 블록체인 모델은 '체인코드'라는 스마트 계약(컨트랙트)를 실행하며 허가된 사용자만 네트워크에 참여할 수 있다. 또한, '채널' 기능이 있어 서로 다른 조직 간의 데이터 공유와 검증에 대한 새로운 접근방식을 보여줄 수 있으며, 특정 네트워크 내에서 데이터를 분리할 수 있다. 이를 통해 특정 데이터에 대한 접근권한을 제어하는 기능을 제공하며 동시에 데이터의 신뢰성과 보안성을 높일 수 있다. 마지막으로 '피어'는 체인코드를 통해 들어온 트랜잭션을 검증하고, 유효한 데이터만 원장에 추가하는 기법으로 무결성을 유지하는 데 중요한 역할 담당하고 있다. 본 연구결과를 기반으로 하이퍼레저 패브릭을 효과적으로 활용하여 데이터 검증 프로세스가 산업계에 널리 적용될 수 있기를 기대한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.05a
• /
• pp.203-204
• /
• 2018

In recent years, interest in various virtual currencies has been increasing, starting with bit coin, and investment and trading of virtual currencies are being activated. However, since the price of virtual money is unstable and the rate of change of the price is very large, frequent confirmation of the amount of money is required, so that virtual money investors often have to check the virtual money market. Therefore, in this paper, we expect that it will reduce the wasted time on the exchange by using the price information guidance system that collects the virtual currency price information data and express it in RGB, and only the system user can understand the data expression and support the confidentiality.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.13 no.3
• /
• pp.1-9
• /
• 2017

Recently, Bitcoin which is digital currency and cryptocurrency is getting worldwide attention since Bitcoin has an ability to replace legal tender unlike other existing cyber currency. Especially, most Bitcoin trading is done between two traders such as P2P method and it does not require a third-party to make sure reliability and it records every transaction details, so it is more transparent then traditional financial trade, so the number of users is increasing. However, Bitcoin, which has been recognized for transparency, confidentiality and stability among traders has recently been threatened by illegal transactions such as money laundering and the attack on the exchange. These threats to Bitcoin are becoming social problems. At first, it seems that most of the digital currency is difficult to get hacked due to the Blockchain technology. However, threats such as digital money leaks by user account hacking and paralyzing the servers are increasing. In this paper, it will examine the features of the Bitcoin and the threatening elements to secure marketability of digital currency such as Bitcoin and receive more interest from public in domestic. The paper will examine the problems of Blockchain technology on speculative transactions and fraudulent behavior by analyzing the problems of Bitcoin transaction. Lastly, it will propose ways to make transparent and secure digital currency transactions.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2019.10a
• /
• pp.737-741
• /
• 2019

최초의 암호화폐인 비트코인과 동시에 등장한 블록체인 기술은 시대를 지나며 발전을 거듭하여 현재는 많은 사람들의 관심을 이끄는 기술이 되었다. 블록체인은 내용을 손쉽게 변경할 수 없는 특징을 지니며 그에 따라 강한 신뢰도를 지니게 된다. 이러한 특징으로 인해 블록체인은 암호화폐 뿐만 아니라 다양한 분야에서 사용되기 시작했다. 우리는 본 특징을 활용하여 블록체인 기반의 애완동물 등록제를 제안한다. 현재 애완동물 산업은 규모가 상당히 거대하며 애완동물은 주인에게 강한 책임이 주어진다. 국내에서는 동물등록제를 통해 동물을 관리하지만 다른 법령과 상충되는 부분 때문에 의미가 퇴색하며 실효성에 이의가 제기되고 있다. 블록체인을 활용한 동물등록제는 부분적으로 공개된 환경에서 정보를 공유하며 분양 등의 사유로 주인이 변경되었을 경우 이를 손쉽게 추적할 수 있는 기반을 제공한다. 따라서 현재 동물등록제의 단점을 크게 해소할 수 있을 것으로 예상되며 다양한 장점을 지니기에 제안하는 바이다.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.29 no.2
• /
• pp.309-320
• /
• 2019

Blockchain has been developed as a key technology for many cryptocurrency systems such as Bitcoin. These days, blockchain technology attracts many people to adopt it to various fields beyond cryptocurrency systems for their information sharing and processing. However, with the development and increasing adoption of the blockchain, security incidents frequently happen in the blockchain systems due to their implementation flaws. In order to solve this problem, in this paper, we analyze the software vulnerabilities of Bitcoin and Ethereum, which are the most widely used blockchain applications in real world. For that purpose, we conduct an in-depth analysis of source code of them to detect software vulnerabilities, and examine an OS command injection attack exploiting the detected ones.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.6
• /
• pp.201-206
• /
• 2018

As the artificial intelligence and big data technology has been developed recently, the importance of GPGPU, which is a general purpose graphics processing unit, is emphasized. In addition, by the demand for mining equipment to obtain bit coins, which is a block chain application technology, the price of GPGPU has increased sharply with scarcity. If a GPGPU can be precisely simulated, it is possible to conduct experiments on various GPGPU types and analyze performance without purchasing expensive ones. In this paper, we investigate the configuration of a GPGPU simulator and measure the performance of various benchmark programs using GPGPU-Sim.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2019.05a
• /
• pp.67-70
• /
• 2019

Blockchain, which emerged with the development of IT technology, has emerged as a new technology in security in recent years, although it has only been known as a technology associated with digital currencies, such as bitcoin. In particular, various studies have been conducted involving biometric technology and blockchain in the security of the mobile environment, and blockchain-based certifications between different devices are also presented in the IoT base of the wireless mobile environment. In this paper, we want to analyze the trends that are currently being applied to various wireless mobile environments and set up guidelines for future blockchain research.