Search

Currently, Raft, as an mainstream consensus mechanism, has received widespread attention. Partition consensus can reduce the number of nodes involved in a single consensus and improve consensus efficiency. However, existing algorithms suffer from unreasonable partitioning and intolerance of Byzantine nodes. To address these problems, this paper proposes a novel Raft consensus algorithm combining comprehensive evaluation partitioning and Byzantine fault tolerance, CB-Raft. First, a comprehensive evaluation of nodes is conducted from the perspectives of consensus behavior and location, and the nodes are evenly divided based on the parity of the comprehensive ranking. Second, the leader is selected from the nodes with the top rankings in the comprehensive evaluation, and the nodes communicate with each other based on BLS signatures. Finally, a fast response mechanism based on cross-partition leader-follower communication is proposed to avoid the continued evil behavior of the leader, and a pipeline mechanism based on changeable signature thresholds is proposed to solve consensus blocking. The experimental results show that compared with the existing partitioning methods, the proposed partitioning scheme has significant advantages in terms of consensus latency, throughput, and the probability of partition success. Compared with the similar Raft algorithms, CB-Raft has high consensus performance and good resistance to Byzantine nodes. [ABSTRACT FROM AUTHOR]

Consensus mechanism (CM) is the heart and soul of blockchain, for it allows nodes in a blockchain network to reach an agreement on the state of system execution. Among the CMs, the right for constructing the next new block is regarded as the most important one since it is required for the blockchain to grow so that transaction data can be recorded in it. Proof-of-work (PoW) is an efficient CM since it allows all the nodes to participate equally in the competition for the right. However, high energy consumption makes PoW less desirable for applications. Moreover, application-oriented blockchains should employ CMs that could reflect some main characteristics of the applications to facilitate the development of other mechanisms, such as the incentive mechanisms. Proof-of-contribution (PoC) is an effective, application-oriented CM since the right for constructing the next new block is determined by contributions made by the nodes and the node that has accumulated the highest contribution value (CV) gets the right. PoC is a general-purpose CM since the behavior of nodes can be characterized in the form of contributions. However, the deterministic nature of PoC as the result of ranking nodes based on CVs may lower efficiency since nodes could fail to function due to network delay, node failure or node's simply dropping out of the network. This paper proposes to design highly effective and efficient CMs by integrating PoC with PoW, which we refer to as PoCW. In PoCW, nodes compete for the right for constructing the next new block based on PoW after being assigned different difficulty values (DVs) based on the ranking of their CVs. Since assigning DVs strictly according to the ranking of CVs would make PoCW resemble PoC while assigning the same DV to all the nodes would make PoCW the same as PoW, PoCW could be designed as a class of CMs through applying different DV assignment strategies to meet the effectiveness and efficiency requirements of a variety of applications. We can further apply the same principle at finer levels of granularity by dynamically grouping nodes along the ranking of CVs and then applying different DV assignment strategies to different groups. The paper will first describe a generic PoCW without involving node grouping and then present the design of a general PoCW through applying an example node grouping method to demonstrate the feasibility of PoCW as a general-purpose CM for blockchain-based applications. Experiments were also conducted to demonstrate the effectiveness and the efficiency of PoCW as well as its advantages over comparable CMs. [ABSTRACT FROM AUTHOR]

The rapid development of network technology makes the implementation of ubiquitous tasks possible in which the Flying Ad-Hoc Network(FANET) plays an important role. Control stations distributed in different task areas can control UAVs in FANET to complete a complex task. However, the application of FANET brings about problems of identity security and data security. Attackers can impersonate legal entities to issue fake commands or modify task data, which will hinder the smooth execution of tasks. The existing centralized entity authorization method has the single point of failure problem, and the distributed method based on the blockchain does not consider the entity security and data security issues at the task level. Therefore, to protect the entity identity security and task data security of ubiquitous tasks in FANET, in this paper, we propose a blockchain-based ubiquitous entity authorization and management scheme (BUAMH), which uses smart contracts and homomorphic encryption technology to achieve entity registration, access control and dynamic task member management. Specifically, the blockchain is used to record and protect entity behavior information and the results of smart contracts. Five smart contracts are designed to realize the authorization and management of entity identity. Besides, Homomorphic encryption technology is used to manage UAVs while protecting entity privacy. Furthermore, a side-chain structure is constructed and an identity consensus mechanism(ICM) is proposed to manage multi tasks and speed up the consensus of miners, respectively. The experimental results show that the computational costs and communication costs of the proposed BUAMH are superior to the existing technology. [ABSTRACT FROM AUTHOR]

Blockchain technology is widely used in various fields due to its high security and reliability. And Unmanned aerial vehicle (UAV)-assisted edge computing is easy to deploy, fast, and flexible. Combining blockchain technology with UAV-assisted edge computing is a hot research topic today. In order to improve the problem of the high overhead of node communication in this environment. In this paper, a primary node selection method based on node reputation evaluation is proposed. In the traditional Practical Byzantine Fault Tolerance (PBFT) algorithm, the efficiency of node communication is very low when the number of nodes becomes large. The algorithm proposed in this paper selects the primary node based on the reputation value, which not only reduces the probability that the primary node is the wrong node but also reduces the number of communications and the communication overhead during the communication process, based on the node identity determined by the node reputation. In the experimental results, three benchmarks are selected for comparison experiments, and it is concluded that the algorithm proposed in this paper can effectively reduce the communication overhead in the PBFT algorithm, reduce the communication delay and improve the efficiency of nodes. [ABSTRACT FROM AUTHOR]

Traditional solutions in commerce scenarios rely on core nodes for global data management. This approach often struggles to balance security and user experience. To address these shortcomings and take advantage of the decentralization and privacy protection offered by blockchain technology, we propose a decentralized commerce data management model. This model aims to ensure secure and efficient transactions in complex network and trust environments. Firstly, the drawbacks of the traditional scheme are analyzed, and the technical advantages of blockchain technology to ensure data security are clarified; secondly, the framework and smart contract implementation scheme are proposed for the characteristics of trade scenario; then, a node selection scheme based on reputation and Quality of Service is designed to meet its performance requirements, and the consensus algorithm is optimized. Finally, the security of the platform in the trade transaction process is verified and analyzed, and the simulation results prove that our proposed scheme, which take credit and dynamic group management into account, can better improve user experience while reducing resource consumption, and optimize the overall network latency and throughput performance. [ABSTRACT FROM AUTHOR]

Modern industrial systems are mostly integrated with the IoT ecosystem for rapid communication with the Internet of Things (IoT). In industrial systems, the interaction among different devices requires a secure, efficient, and robust IoT infrastructure. Emerging blockchain technology provides highly secure network nodes to support industrial systems and IoT. This work discusses the current state of blockchain integration with industrial IoT systems. In order to improve the security of Industrial IoT, a DAG-based consensus model is developed to addresses the issues in the generic blockchain network. We compared the merits of the DAG-based blockchain model with the Proof of Work (PoW) and Proof of Stake (PoS) consensus mechanism. Moreover, a main integration of DAG-based blockchain technology with industrial IoT and key challenges are presented with evaluation results. The performance evaluations are carried out with the help of block weight, ledge scalability and IIoT reliability analysis. [ABSTRACT FROM AUTHOR]

In the process of continuous development of rural economy, big data management plays an important role. Rural economic data mainly include rural labor force, added value of agriculture, forestry, fishery and animal husbandry, agricultural product output and per capita net income. Using big data to manage economic data can not only integrate and analyze a large number of data, build an economic management analysis database, but also predict and warn related risks in time and provide reasonable and effective economic management suggestions, thus ensuring the smooth operation of the economy. However, there are some shortcomings in data reliability, data quality and data management efficiency in rural regional economic data management, which have a great impact on the long-term stable development of the economy. This paper makes a systematic analysis of rural regional economic data, uses the blockchain consensus mechanism to quickly manage and analyze different types of economy in rural areas, and improves the speed of economic data analysis through smart contracts. This paper makes a comparative analysis of rural regional economic data management before and after adopting blockchain technology. In view of this phenomenon, according to the development demand of data management, this paper uses blockchain technology to effectively analyze and study the big data management of rural regional economy, and makes a comparative analysis through the tests of data operation efficiency, data quality, data management security and sharing degree. The experimental data show that the efficiency of data operation is as high as 1100 times per minute after the combination of blockchain technology, and the minimum manual modification ratio of node data is 0.24. This shows that the data quality of technical means is guaranteed. The data leakage rate per hour is at least 66%, and the data sharing volume is maintained at about 8000 views/hour and 7000 references/hour. The improvement of quality and efficiency can ensure the effectiveness of data management and improve the speed of economic development in rural areas, thus promoting good economic development. This paper uses blockchain technology to manage rural economic data, which has certain reference value for rural economic development. [ABSTRACT FROM AUTHOR]

The performance of blockchains is a critical issue in various applications, such as digital currency transactions and balance checking. Blockchain system architectures such as the Hyperledger Fabric blockchain system (HFBS) have decentralized modular functions, where each module runs on an independent set of hosts. This study conducts a series of experiments to understand the performance limitations of each modular operation in a blockchain system architecture. Three studies involving software programs installed on cloud computing platforms are conducted to evaluate the transaction processing bottleneck. We present an improved modular configuration to enhance the cost efficiency of consortium blockchain systems. Although the CLI module consumes the largest processing resource, the scaled features make the traffic load distributed. The endorsing module is actually bottleneck due to inextensibility and state database. Experimental results obtained from the state database and system performance evaluation indicate that the performance of the state database is highly related to the read-type transactions of the HFBS but not to the write-type transactions. We argue that the performance bottleneck of read operations can be attributed to the fact that CouchDB cannot achieve high system performance under a large number of query operations. When querying the internal text in CouchDB, the system scans the entire data table. Thus, performance and scalability bottlenecks occur for CouchDB. Accordingly, we propose the adoption of MySQL Document Store, which uses a binary storage format similar to that of the state database of HFBS. The experimental results confirm that MySQL Document Store outperforms CouchDB and native state database. The consequent increase in the operational efficiency of the state database enhanced the operational performance of the HFBS. The practical contribution of this study is that its findings can serve as a reference for system structure design for developers and indicate suitable strategies that can be deployed by developers in blockchain systems. [ABSTRACT FROM AUTHOR]

This exploration aims to effectively improve the data security of the financial poverty alleviation system, and provide a new idea for realizing highly credible targeted poverty alleviation. The centralized structure of the existing targeted poverty alleviation system leads to excessive power and a lack of trust. Hence, a decentralized targeted poverty alleviation system based on Ethereum blockchain technology of Internet of things technology is proposed. The system records personnel information, poverty alleviation data and funds in the blockchain to ensure the data credibility and security. A method of combining blockchain and InterPlanetary File System is proposed to jointly maintain the query and storage of large text data. It reveals that the application products using Ethereum blockchain technology have the characteristics of distribution, autonomy, contract execution and traceability. They will become mainstream applications in future development and can help society enter a highly trusted big data era. Ethereum blockchain has grown in the financial field and other fields. Moreover, the new model of Ethereum blockchain combined with government work can make government work more standardized, rigorous and credible. The research contribution is to propose an architecture based on Ethereum blockchain technology to realize automatic transaction generation and processing by combining smart contracts. [ABSTRACT FROM AUTHOR]

The practical Byzantine fault tolerant (PBFT) consensus mechanism is one of the most basic consensus algorithms (or protocols) in blockchain technologies. Thus its performance evaluation is an interesting and challenging topic due to the higher complexity of its consensus work in a peer-to-peer network. This study describes a simple stochastic performance model of the PBFT consensus mechanism. This model is refined not only as a queuing system with complicated service times but also as a level-independent quasi-birth-and-death (QBD) process. With regard to the level-independent QBD process, we apply the matrix-geometric solution to obtain the necessary and sufficient condition under which the PBFT consensus system is stable and then numerically compute the stationary probability vector of the QBD process. Thus, we provide four useful performance measures for the PBFT consensus mechanism, and we can numerically calculate these performance measures. Finally, we use numerical examples to verify the validity of our theoretical results and demonstrate how the four performance measures are influenced by certain key parameters of the PBFT consensus. Considering theory of multi-dimensional Markov processes, we are optimistic that the methodology and results presented in this study are applicable to a wide range of PBFT consensus mechanism and even other types of consensus mechanisms. [ABSTRACT FROM AUTHOR]

As the number of devices joining the Internet of Things (IoT) keeps increasing, vast amounts of data are being mined, and data sharing can exploit their considerable value. Owing to its advantages of decentralization, consistency, and traceability, blockchain technology can be used to build an efficient and reliable IoT data sharing system. To facilitate the use of blockchain in IoT devices, we design a new slicing- and coding-based consensus algorithm (SCCA). The proposed consensus algorithm considers the storage optimization of the blockchain ledger. Specifically, the SCCA slices and encodes consensus resources and divides the blockchain nodes into different domains. It allows multiple domains to perform consensus concurrently and collaborate to store the blockchain ledger. Finally, we construct an experimental platform and evaluate the scheme. Experimental results reveal that the SCCA can increase throughput by more than five times and reduce communication costs by 95.7%, compared to the practical Byzantine fault tolerance method. In addition, the SCCA can reduce the storage cost of a single node to approximately 28.5% of that of the Bitcoin system. [ABSTRACT FROM AUTHOR]

With the increasingly complex social situation, the problems of traditional online public opinion governance are increasingly serious. Especially the problem of transmission efficiency, public opinion data management and user information security of Internet users is urgently needed. Here, we design a functional infrastructure framework of the network public opinion collaborative governance model based on the blockchain with strong practicality and comprehensiveness. In order to reach the consensus mechanism requirements under the framework, the algorithm is improved on the basis of the defects of the traditional DPoS consensus algorithm. Considering time dynamic factors in the process of reaching consensus, the paper proposes a reputation-based voting model. Furthermore, the paper purposes a rewards and punishments incentive mechanism, and also designs a new method of counting votes. From the simulation results, it was found that after the improvement of the algorithm, the enthusiasm of node participation was significantly increased, the proportion of error nodes was significantly reduced, and the operating efficiency was significantly improved. It shows that the improved consensus algorithm we propose applies to public opinion governance can not only improve the security of the system with the reduce of false public opinion spreading, but also improve the efficiency of information processing, so it can be well applied to information sharing and public opinion governance scenarios. [ABSTRACT FROM AUTHOR]

Existing public blockchain architectures suffer from the difficulty of scaling to support large-scale networks with high TPS, low latency and security. Using the idea of network fragmentation, an improved Raft-based PBFT consensus mechanism is proposed to solve the problem. The network nodes are grouped, and the group adopts the improved Raft mechanism for consensus, and then, the leaders elected in each group form the network committee, and the network committee uses the PBFT mechanism for consensus within the network committee. The results show that R-PBFT is more scalable than PBFT and Raft in a large-scale network environment because it can guarantee high consensus efficiency while having Byzantine fault tolerance; similarly, to improve the fairness between user experience and TPS in blockchain systems, based on the transaction fairness model, a fairness packing algorithm is proposed for storing transactions. It is based on a two-level model, firstly sorting the transactions in descending order based on GasPrice, moreover considering the fairness model for descending order. The experimental confirmed that all the performance of fairness packing is superior to Ethereum packing. [ABSTRACT FROM AUTHOR]

Resource allocation aims at using the storage, computing and bandwidth between edge servers and end users while satisfying the requirement of different application scenarios. However, there are some security threats in the allocation process, such as unreal resources and denial of service, in which the trusted resource allocation becoming a critical research content. Blockchain technology is one important solution for this problem, but the high-delay and low-throughput shortcomings in blockchain cannot fulfill the requirements of time-sensitive applications. In this paper, we firstly utilize a reputation evaluation mechanism to calculate and rate the servers' reputation values in the resource allocation process. The high-reputation servers are added as candidate leaders into a block generation group, while the remaining low-reputation edge servers are added as verifiers into a block verification group. Secondly, we utilize a round-robin mechanism to choose a leader from the block generation group. The leader is responsible for generating a new block in each timeslot and is updated in different timeslots. Thirdly, we utilize a reward and punishment mechanism to encourage low-reputation servers to participate in consensus. Finally, we propose a proof-of-reputation consensus mechanism to realize the trusted resource allocation based on smart contracts, which can match the end users with high-reputation edge servers automatically. Simulation results show the consensus delay and throughput of resource allocation achieve significant performance improvements in comparison with current schemes, and the system is more sensitive to dishonest edge servers and quickly reduces their reputation values. [ABSTRACT FROM AUTHOR]

Nowadays, people trade electricity through centralized companies or organizations which is vulnerable to cyber attacks and incapable of coping with increasing demands from stakeholders. In this paper, we propose a new Peer-to-Peer Electricity Blockchain Trading (P2PEBT) system based on the current charging and discharging schemes for electric vehicles (EV) in the smart grid to enable users to participate in the trading process. In order to cope with the current situation of the high volume of EV integration, the proof-of-Benefit (PoB) consensus primitives are proposed for P2PEBT to achieve demand response by providing incentives to balance local electricity demand in the novel blockchain system. PoB is implemented by executing the smart contracts on the Ethereum platform, and the process of achieving the maximal benefits is completed by submitting the transaction in the decentralized network. Security analysis shows that the P2PEBT system is able to manage a potential protection against up to a number of attacks. We demonstrate that the proposed system using the PoB consensus mechanism can achieve lower power fluctuation without requiring a third-party intermediary. [ABSTRACT FROM AUTHOR]

The cheque based banking transactions are widely used all over the world. The reason is that it is a hustle free and trusted way of money transaction. The existing cheque settlement process involves manual processing of submitted cheques, and large amounts of time for clearance. This paper proposes a framework to automate the cheque settlement process. This framework proposes cheque generation, cheque processing and cheque settlement process through online and physical modes. The proposed framework is based on blockchain technology, where the blockchain network brings all different banks on a common platform i.e. the e-cheque issued from one bank can be submitted to any other bank in any mode of operation either physical or online. The proposed framework comprises a novel trust based consensus mechanism for block mining. The proposed consensus approach outperforms the existing proof-of-work based approach by reducing consensus time by 25%. The proposed framework can partially transform the current banking system over the blockchain. Security threats and vulnerability of the proposed framework is also discussed in this paper. [ABSTRACT FROM AUTHOR]

Background: Bitcoin system, when more than 51% computing power is controlled by a single node, the block chain can be distorted maliciously. This is called 51% attack which is a well-known potential risk that could destroy the Bitcoin system. Method: The paper proves that under the current proof-of-work mechanism, computing power eventually will be centralized at a single node if miners are rational enough. Result: The paper propose a new proof-of-work mechanism that improves decentralization and reduces the risk of 51% attack without increasing the risk of Sybil attack. Concusions: This new mechanism introduces a series of principles such as Career open to all talents, without distinction of birth, Distribution according to labor and All Men are created equal. [ABSTRACT FROM AUTHOR]