• Proceedings of the Korea Information Processing Society Conference
• /
• 2019.10a
• /
• pp.106-109
• /
• 2019

비트코인은 분산시스템으로 많은 노드를 가질수록 가용성 및 안정성이 유지된다. 이를 위해서는 블록 크기가 작고 많은 트랜잭션을 처리할 수 있는 구조를 가지는 것이 유리하다. 비트코인의 트랜잭션이 많아지면서 2017 년 8 월 24 일 세그윗(SegWit) 이후에 블록사이즈는 1MB 에서 2MB 로 변경되었고, 2019 년 9 월 현재 블록당 사이즈는 1MB 이상이 사용되고 있다. 이러한 추세라면 가까운 시일 내에 최대 블록사이즈에 근접하게 될 것이다. 본 논문에서는 세그윗 적용에 따른 비트코인의 변화를 조사하여 세그윗을 적용하지 않은 레거시(Legacy) 노드와의 차이점과 소프트포크(Softfork)로 알려진 호환성(Backward Compatibility)을 살펴보고, 세그윗을 통해 가단성(Malleability) 버그가 해결과 블록 사이즈 증가를 통해 TPS(Transaction Per Second)가 향상되는 것을 확인하고자 한다.

• 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.

• Electronics and Telecommunications Trends
• /
• v.33 no.6
• /
• pp.139-153
• /
• 2018

The explosive interest in block chain, which was triggered by Bitcoin in 2009, is leading to substantial investment and the development of block chain technology. There is no dispute among experts that block chain will be the next generation of innovation. However, despite the high expectations for block chains, the related technology still has certain limitations. In addition to improving issues such as a low transaction throughput, inefficient agreement algorithms, and an inflexible governance structure, it is necessary to solve various problems for commercialization and full-scale spreading owing to the trilemma problem among the scalability, security, and decentralization. Under this situation, identification of the technology characteristics according to the generation is helpful for the development of the core technology requirements and commercialization blueprint in establishing an R&D direction. Therefore, in this article, the development of blockchain technology is divided into generations and analyzed in terms of the operational structure, consensus algorithm, governance, scalability, and security.

• International Journal of Computer Science & Network Security
• /
• v.21 no.4
• /
• pp.9-18
• /
• 2021

Blockchain and its infrastructure technology have expanded rapidly in the last decade and are in high demand, but there is a lack of comprehensive studies on those platforms. Blockchain is a new technology based on the distributed digital ledger system. Decentralized trust is one of the key factors behind the blockchain-based system. Transparency of such a system is better than a conventional centralized ledger system. By using a blockchain-based transaction system, any business organization can harness key benefits like data integrity, confidentiality, and anonymity without involving any third party in control of the transactions. Since the blockchain is used in numerous applications and the horizon is expanding at an unprecedented pace. So, there is a need for an introducing and reviewing of blockchain platforms. In this paper, we have reported a review on existing contemporary blockchain platforms. In particular, From the existing studies, we have identified eighty blockchain platforms and the majority of them have a lack of technical details. To provide the researchers a comprehensive introducing on blockchain platforms to perform a broad guideline for future research and investment in the blockchain domain.

• Electronics and Telecommunications Trends
• /
• v.37 no.1
• /
• pp.63-72
• /
• 2022

Recently, blockchain has been attracting attention as a high-reliability technology in various fields. However, the Proof-of-Work-based distributed consensus algorithm applied to representative blockchains, such as Bitcoin and Ethereum, has limitations in applications to various industries owing to its excessive resource consumption and performance limitations. To overcome these limitations, various distributed consensus algorithms have appeared, and recently, hybrid distributed consensus algorithms that use two or more consensus algorithms to achieve decentralization and scalability have emerged. This paper introduces the technological trends of the latest high-performance distributed consensus algorithms by analyzing representative hybrid distributed consensus algorithms.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.16 no.3
• /
• pp.861-876
• /
• 2022

Cryptoassets such as Bitcoin and Ethereum are widely traded around the world. Cryptocurrencies are also transferred between investors. Cryptocurrency has become a new and attractive means of remittance. Thus, blockchain-based smart contracts also attract attention when central banks design digital currencies. However, it has been discovered that a significant amount of cryptoassets on blockchain are lost or stranded for a variety of reasons, including the loss of the private key or the owner's death. To address this issue, we propose a method for recoverable transactions that would replace the traditional transaction by allowing cryptoassets to be sent to a backup account address after a deadline has passed. We provide the computational workload required for our method by analyzing the prototype. The method proposed in this paper can be considered as a good model for digital currency design, including central bank digital currency (CBDC).

• Journal of Information Technology Applications and Management
• /
• v.29 no.2
• /
• pp.17-25
• /
• 2022

Although the two types of currencies compete, the possibility of a virtual currency price bubble is diagnosed by assuming an economic model with currencies (won, virtual currency) that are intrinsically worthless. The won is supplied by the central bank to achieve the price stability target, while the supply of virtual currency increases by a fixed number. According to the basic price theory equation, as a simple proposition, cryptocurrency prices form a Martin Gale process [Schilling and Uhlig, 2019, p.20]. Based on the existing theoretical proposition, we applied the variance ratio verification method [Linton and Smetanina, 2016] and a simple technical chart method for empirical analysis. For the purpose of this study, the possibility of a bubble was empirically analyzed by analyzing the price volatility formed in the Korean virtual currency market over the past year, and brief policy implications for this were presented.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2021.05a
• /
• pp.466-469
• /
• 2021

최근 암호화폐가 발전함에 따라 다양한 연구들이 진행되고 있지만 그 중에서도 암호화폐의 가격 예측 연구들이 활발히 진행되고 있다. 특히 이러한 예측 분야에서도 인공지능 기술을 접목시켜 암호화폐 가격의 예측 정확도를 높이려는 노력들이 지속되고 있다. 인공지능 기반의 기법들 중 시간적 정보를 가진 데이터를 기반으로 하고 있는 LSTM(Long Short-Term Memory) 모델이 다각도로 활용되고 있으나 급등락하는 암호화폐 가격 데이터가 많을 경우에는 그 성능이 상대적으로 낮아질 수 밖에 없다. 따라서 본 논문에서는 가격이 급등락하고 있는 Bitcoin, Ethereum, Dash 암호화폐 데이터 환경에서 LSTM 모델의 예측 성능이 향상될 수 있는 세부 하이퍼 파라미터 값을 실험 및 분석하고, 그 결과의 의미에 대해 고찰한다. 이를 위해 LSTM 모델에서 향상된 예측률을 보일 수 있는 epoch, hidden layer 수, optimizer 에 대해 분석하였고, 최적의 예측 결과를 도출해 줄 수 있는 최소 training data 개수도 함께 살펴보았다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2022.11a
• /
• pp.440-442
• /
• 2022

2017년 가치가 급상승하며 전 세계적으로 큰 이슈를 끈 비트코인은 최근 많은 사람들의 재태크 수단으로 이용되고 있다. 그러나 비트코인은 비슷한 재태크 수단인 주식과 다르게 24시간 내내 거래되고, 기사 하나하나에 의해 가격변동의 폭이 굉장히 크다. 이는 가격이 급변하는 비트코인 시장에서 가격을 예측하는데 어렵게 작용한다. 본 논문에서는 직접적인 가격 예측은 어렵다고 판단해 비트코인 가격변동에 영향을 주는 요소들을 딥러닝 모델을 통해 일일 단위 종가 가격의 등락을 예측해 위의 요소들이 비트코인 가격변동과 상관관계를 가지는지 확인한다.

• Journal of Digital Convergence
• /
• v.18 no.11
• /
• pp.129-136
• /
• 2020

The advantages of Blockchain present the necessity of Blockchain in various fields. However, there are several disadvantages to Blockchain. Among them, the uncle block problem is one of the problems that can greatly hinder the value and utilization of Blockchain. Although the value of Blockchain may be degraded by the uncle block problem, previous studies did not pay much attention to research on uncle block. Therefore, the purpose of this study attempts to predict the occurrence of uncle block in order to predict and prepare for the uncle block problem of Blockchain. This study verifies the validity of introducing new attributes and ensemble analysis techniques for accurate prediction of uncle block occurrence. As a research method, voting, bagging, and stacking ensemble analysis techniques were employed for Ethereum's uncle block where the uncle block problem actually occurs. We used Blockchain information of Ethereum and Bitcoin as analysis data. As a result of the study, we found that the best prediction result was presented when voting and stacking ensemble techniques were applied using only Ethereum Blockchain information. The result of this study contributes to more accurately predict the occurrence of uncle block and prepare for the uncle block problem of Blockchain.