• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.10a
• /
• pp.249-251
• /
• 2021

PBFT (Practical Byzantine Fault Tolerant) is a consensus algorithm that guarantees higher processing speed compared to PoW (Proof of Work) and absolute finality that records are not overturned due to the superiority of computing power. However, due to the complexity of the message, there is a limit that the network load increases exponentially as the number of participating nodes increases. PBFT is an important factor in determining the performance of a blockchain network, but studies on evaluation metrics and evaluation technologies are lacking. In this paper, we propose a PBFT evaluation framework that is convenient to change the consensus algorithm to easily evaluate quantitative indicators and improved methods for evaluating PBFT.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.26 no.2
• /
• pp.271-277
• /
• 2022

PBFT (Practical Byzantine Fault Tolerant) is a consensus algorithm that can achieve consensus by resolving unintentional and intentional faults in a distributed network environment and can guarantee high performance and absolute finality. However, as the size of the network increases, the network load also increases due to message broadcasting that repeatedly occurs during the consensus process. Due to the characteristics of the PBFT algorithm, it is suitable for small/private blockchain, but there is a limit to its application to large/public blockchain. Because PBFT affects the performance of blockchain networks, the industry should test whether PBFT is suitable for products and services, and academia needs a unified evaluation metric and technology for PBFT performance improvement research. In this paper, quantitative evaluation metrics and evaluation frameworks that can evaluate PBFT family consensus algorithms are studied. In addition, the throughput, latency, and fault tolerance of PBFT are evaluated using the proposed PBFT evaluation framework.

• Journal of KIISE:Computing Practices and Letters
• /
• v.14 no.5
• /
• pp.487-491
• /
• 2008

This paper proposes the Byzantine fault tolerant clock synchronization scheme for wireless sensor networks to cope with the clock synchronization disturbance attack of malicious nodes. In the proposed scheme, a node which is requiring clock synchronization receives 3m+1 clock synchronization messages not only from its parent nodes but also from its sibling nodes in order to tolerate malicious attacks even if up to m malicious nodes exist among them. The results show that the proposed scheme is 7 times more resilient to the clock synchronization disturbance attack of malicious nodes than existing schemes in terms of synchronization accuracy.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.7
• /
• pp.3351-3368
• /
• 2019

The Internet of Things (IoT) enables machines and devices in a global network to connect and provide applications. The Vehicular Ad-hoc NETwork (VANET) allows vehicles in the network to communicate with each other as an application of the IoT. The safety and comfort of passengers can be improved through VANET related applications. In order to be able to provide related applications, there must be a reliable VANET topology. As a result of the Byzantine agreement (BA), fault tolerance can be solved in VANET. In order to improve the reliability of the system, even if some components in the system are damaged, a protocol is needed to assist the system to perform normally. Therefore, the BA problem in VANET with multiple impairments is revisited in this research. The proposed protocol allows all normal processing elements (PEs) to reach agreement using the least amount of information exchange. Moreover, the proposed protocol can tolerate the largest number of damaged PEs in VANET.

• Convergence Security Journal
• /
• v.20 no.3
• /
• pp.71-78
• /
• 2020

Bitcoin-based blockchain technology provides an infrastructure that enables anonymous smart contracts, low-cost remittances, and online payments. However, the block-chain technology that implements the bitcoin has scalability constraints in tradeoffs between throughput and latency. To solve these problems, the Byzantine fault tolerant block-chain technique has been proposed. This technique improves throughput without increasing latency by selecting a leader and constructing many microblocks that do not contain proofs of work within the existing block by the leader. However, this technique may be less secure than existing techniques in selecting the reader.

• Journal of Information Processing Systems
• /
• v.16 no.2
• /
• pp.301-317
• /
• 2020

An enterprise patch-management system (PMS) typically supplies a single point of failure (SPOF) of centralization structure. However, a Blockchain system offers features of decentralization, transaction integrity, user certification, and a smart chaincode. This study proposes a Hyperledger Fabric Blockchain-based distributed patch-management system and verifies its technological feasibility through prototyping, so that all participating users can be protected from various threats. In particular, by adopting a private chain for patch file set management, it is designed as a Blockchain system that can enhance security, log management, latest status supervision and monitoring functions. In addition, it uses a Hyperledger Fabric that owns a practical Byzantine fault tolerant consensus algorithm, and implements the functions of upload patch file set, download patch file set, and audit patch file history, which are major features of PMS, as a smart contract (chaincode), and verified this operation. The distributed ledger structure of Blockchain-based PMS can be a solution for distributor and client authentication and forgery problems, SPOF problem, and distribution record reliability problem. It not only presents an alternative to dealing with central management server loads and failures, but it also provides a higher level of security and availability.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.10a
• /
• pp.569-570
• /
• 2017

Bitcoin-based blockchain technology provides an infrastructure that enables anonymous smart contracts, low-cost remittances, and online payments. However, the block-chain technology that implements the bitcoin has scalability constraints in tradeoffs between throughput and latency. To solve these problems, the Byzantine fault tolerant block-chain technique has been proposed. This technique improves throughput without increasing latency by selecting a leader and constructing many microblocks that do not contain proofs of work within the existing block by the leader. However, this technique may be less secure than existing techniques in selecting the reader. In this paper, we propose a technique for scalability of the blockchain technology by using microblock technology and parallel execution technique. Within one microblock there is information about several transactions. In the proposed scheme, the throughput of the microblocks can be increased by performing concurrently.

• Journal of Digital Convergence
• /
• v.17 no.1
• /
• pp.195-201
• /
• 2019

This paper proposes a blockchain system to share Wireless Local Area Network (WLAN) that recently suffers from mutual interference among increasing devices using unlicensed bands. Blockchain technology can induce cooperation from users by incentivizing them with cryptocurrency like shown in Bitcoin example. In this paper, we describe Blockchain based access mechanism in WLAN instead of conventional authentication based access. Here, users can access any WLAN access point by paying through smart contract while they also receive payment from others. In order to support real-time transaction, we apply proof-of-authority that is realized by Byzantine fault tolerant protocol instead of well-known proof-of-work that requires huge computing power and delay.