Blockchain Consensus Research Articles

An Effective and Lightweight Countermeasure Scheme to Multiple Network Attacks in NDN

In Named Data Networking, cache pollution, cache poisoning and interest flooding are three popular types of attacks that can drastically degrade the network performance. However, previous methods for mitigating these attacks are not sufficiently effective or efficient. Also, they cannot simultaneously handle the three attacks, or the case that core routers or edge routers are compromised. To handle these problems, we propose an effective and lightweight countermeasure scheme. It consists of token-based router monitoring policy (TRM), hierarchical consensus-based trust management (HCT), and popularity-based probabilistic caching and caching replacement policy (PPC). In TRM, each edge router monitors and evaluates each data requester’s probability of launching the cache pollution attack and each data provider’s probability of launching the cache poisoning attack, and accordingly assigns, rewards and penalizes tokens to them to control their data request and data provision activities. Thus, the interest flooding attack can also be mitigated by limiting the consumption of tokens. In HCT, each core router manages its directly connected edge routers using TRM, and the core routers trust each other through adopting the concept of consensus in Blockchain. Thus, the edge and core routers executing monitoring and evaluation are trustable. PPC uses probabilistic caching and caching replacement based on the popularity of received content to further mitigate the attacks and reduce caching and data verification overhead. Results from simulation experiments demonstrate that our proposed scheme has better performance, in terms of interest satisfaction ratio and average end-to-end delay than current mechanisms.

On the Robustness of Quantum Algorithms for Blockchain Consensus.

Blockchain has revolutionized many fields, such as distributed sensor networks, finance, and cryptocurrency. Consensus between distributed network nodes is at the core of such blockchain technologies. The three primary performance measures for any consensus algorithm are scalability, security, and decentralization. This paper evaluates the usefulness and practicality of quantum consensus algorithms for blockchain-enhanced sensor, and computing networks and evaluates them against the aforementioned performance measures. In particular, we investigate their noise robustness against quantum decoherence in quantum processors and over fiber-optic channels. We observe that the quantum noise generally increases the error rate in the list distribution. However, the effect is variable on different quantum consensus schemes. For example, the entanglement-free scheme is more affected than entanglement-based schemes for the local noise cases, while in the case of noisy optical fiber links, the effect is prominent on all quantum consensus schemes. We infer that the current quantum protocols with noisy intermediate-scale quantum devices and noisy quantum communication can only be employed for modular units in intraenterprise-level blockchain, such as Zilliqa, for sensor, and computing networks.

Design Guidelines and a Prototype Implementation for Cyber-Resiliency in IT/OT Scenarios Based on Blockchain and Edge Computing

The advent of the Internet of Things (IoT) and its spread in industrial environments has changed production lines by dramatically fostering the dynamicity of data sharing and the connectivity of machines. However, such increased flexibility (also pushed by the adoption of edge devices) must not negatively affect the security and safety of industrial environments. The proposed solution adopts the blockchain to securely store in distributed ledgers topology information and access rules, maximizing the cyber resiliency of industrial networks. Topology information and access rules are stored and queried in a completely distributed manner, ensuring data availability even in case a centralized controller is temporarily down or the network partitioned. Moreover, blockchain consensus algorithms foster a participative validation of topology information, to ensure the identity of interacting machines/nodes, to securely distribute topology information and commands in a privacy-preserving manner, and to trace any past modification in a nonrepudiable manner. Finally, the adoption of configurable edge gateways allows to take prompt countermeasures in case potential threats are identified, by activating access rules stored in ledgers in a secure and distributed manner. In addition to solution design guidelines and architectural considerations, the article also presents performance results achieved with our CyberChain working prototype, with the goal of not only demonstrating the feasibility of the proposed solution but also its suitability in industrial environments.

A Blockchain Consensus Optimization-Based Algorithm for Food Traceability

At present, blockchain technology is more and more widely used in the field of food traceability, and good results have been achieved. However, many of the current blockchain technologies and algorithms are not developed for the specific situation of food traceability, resulting in resource waste and low computational efficiency. In view of these problems, this paper analyzes and summarizes the classic distributed consensus mechanism in blockchain technology, focusing on the PBFT (practical Byzantine fault tolerance) consensus mechanism and the existing problems related to the improvement scheme. In order to solve the problem of low efficiency of a consensus algorithm in a food traceability scenario, this paper proposes a blockchain consensus algorithm suitable for the food traceability scenario based on clustering and food credit. In addition, the differences between the improved algorithm and the classical Byzantine consensus algorithm in consensus algorithm time and communication times are analyzed through experiments and simulations. The consensus efficiency of the improved algorithm in this paper is significantly improved, which can greatly reduce the application difficulty of blockchain in food traceability.

Blockchain-Based Crowdsourcing Framework with Distributed Task Assignment and Solution Verification

Internet backboned crowdsourcing utilizes network-wide resources to solve complicated and large-scale tasks, which are not accomplishable for independent individuals. Existing crowdsourcing platforms are mostly centralized solutions with reliability and trustworthiness fragile to single-point failures on the central servers. The innovation of distributed ledgers as blockchain inspires us to optimize the traditional crowdsourcing procedure with distributed sustainability. We propose a blockchain-based design of the distributed secure crowdsourcing scheme for task distribution and result verification without relying on any third trusted institution. A preference-based task distribution (PTD) mechanism is presented which guarantees the percentage of task distribution and the satisfaction of the chosen workers. Task works are continuously assessed for reputations based on their historical behaviors. Task completion correctness is verified by blockchain consensus in two different scenarios after workers submit their results with reputations. We implement a prototype system based on the Ethereum chain with PTD and solution verification components. With various tasks and scenarios evaluated in the system, the proposed distributed crowdsourcing framework shows system reliability, data security, and scenario feasibility.

An Effective Big Data Sharing Prototype Based on Ethereum Blockchain

Because of its many advantages, big data has been extending to various domains of science, health, education, and commerce. Despite its many applications, big data sharing typically suffers from some key issues, such as user control, lack of incentives, cost, and the right of data. This paper proposes a decentralized big data sharing prototype to improve the applications and services of big data. The method makes use of Ethereum blockchain and related technologies to systematically recommend the implementation guidelines. The research provides a detailed description of the design and implementation of each sublayer of a big data system. As the method is based on blockchain technology, the key technical points are properly addressed in each of the layers. For evaluation, relevant data were collected, and functional testing was performed. A comparison was performed about the sharing frequency and blockchain consensus performance of similar platforms. The dual mining node of the proposed prototype succeeded in processing 1366 blocks and 300 messages. A comparatively satisfactory file access time in the range of 10 m to 20 s and file transmission time between 100 m and 200 s were achieved. The results obtained show that this prototype can effectively verify the feasibility of the model, the layered architecture, and the related sharing mechanism. For the functional and performance testing, practical projects were implemented and evaluated. The promising results obtained testify that the research offers a theoretical background for innovative research in the domain and specialized guidelines for practical implementation.

Leveraging Blockchain for Multi-Operator Access Sharing Management in Internet of Vehicles

Wireless service providers (WSPs) are seeking cooperation to share both resources (spectrum, infrastructures) and costs. In particular, cooperation is critical for vehicle-to-everything (V2X) applications that value quality-of-service foremost. However, cooperation is inefficient without strong trust bases. Recently, blockchain arises as a promising solution to decentralized trust, owing to its transparency and immutability. Therefore, we propose a WSP cooperation framework based on blockchain, which keeps a shared ledger on resource utilization. In this paper, we first study the WSP selection problem of vehicles by evolutionary game. Then, we make the blockchain public to vehicles to maintain its decentralization and enhance its security by crowdsourcing idle computing resources from vehicles. To deal with the mobility of vehicles, as well as to improve the consensus efficiency, we propose delegated proof-of-work (DPoW) scheme, which introduces delegate nodes for participating in the blockchain consensus on behalf of the vehicles. The alternating direction method of multipliers (ADMM) optimization framework is further used to derive optimal consensus parameters including block size, computing resource demand of delegate nodes, and prices paid for vehicles. We conduct extensive simulations to show the effectiveness of the proposed methods.

CICM: A Collaborative Integrity Checking Blockchain Consensus Mechanism for Preserving the Originality of Data the Cloud for Forensic Investigation

The originality of data is very important for achieving correct results from forensic analysis of data for resolving the issue. Data may be analysed to resolve disputes or review issues by finding trends in the dataset that can give clues to the cause of the issue. Specially designed foolproof protection for data integrity is required for forensic purposes. Collaborative Integrity Checking Mechanism (CICM), for securing the chain-of-custody of data in a blockchain is proposed in this paper. Existing consensus mechanisms are fault-tolerant, allowing a threshold for faults. CICM avoids faults by using a transparent 100% agreement process for validating the originality of data in a blockchain. A group of agreement actors check and record the original status of data at its time of arrival. Acceptance is based on general agreement by all the participants in the consensus process. The solution was tested against practical byzantine fault tolerant (PBFT), Zyzzyva, and hybrid byzantine fault tolerant (hBFT) mechanisms for efficacy to yield correct results and operational performance costs. Binomial distribution was used to examine the CICM efficacy. CICM recorded zero probability of failure while the benchmarks recorded up to 8.44%. Throughput and latency were used to test its operational performance costs. The hBFT recorded the best performance among the benchmarks. CICM achieved 30.61% higher throughput and 21.47% lower latency than hBFT. In the robustness against faults tests, CICM performed better than hBFT with 16.5% higher throughput and 14.93% lower latency than the hBFT in the worst-case fault scenario.

Design and implementation of hybrid consensus mechanism for IoT based healthcare system security.

Nowadays, blockchain is emerging as a worthwhile technology for managing sensitive data in electronic healthcare system. It plays an important role in healthcare, medical research and insurance sectors. The consensus algorithms used in blockchain technology for the selection of a new block, provide high-level of security to IoT devices. However, the reliability problem still exists. In the present paper, a blockchain based hybrid consensus mechanism (HCM) is implemented in electronic healthcare system (EHS) to overcome trustworthiness issues. The aim of the proposed HCM is to maintain reputation module on the basis of the block activities. In this context, EHS is designed in four layers namely: system layer, inter-network layer, blockchain layer, and cloud layer. Moreover, HCM consists of five algorithms for creation, validation, fork handling (if any), Merkle tree construction and reward/punishment module respectively. Dev C++ software platform is used for the simulation of the above mentioned HCM algorithms excluding Merkle tree construction which is simulated using conditional contrast high itemset tree. It is observed that all the blocks use same methodology to be the part of a new blockchain network. Moreover, the CPU and memory consumption in the implementation of HCM is always below two percent and about fifty percent respectively as shown in the latency graph. The basic security goal (confidentiality, integrity and availability) is guaranteed with the help of the height of the Merkel tree as well. The performances of the proposed HCM and Proof of X-repute (PoXR) blockchain consensus algorithms are compared with respect to various parameters such as final difficulty, reward and punishment provisions etc. HCM shows superior performance as the final earned reputation is calculated for each block along with the reward and punishment modules during the deployment of blockchain network. In addition, a simple concept of Merkle-tree is opted for providing reward and punishment rather than a set of complex mathematical equations as used in PoXR consensus algorithm.

A Blockchain Based Federated Learning for Message Dissemination in Vehicular Networks

Message exchange among vehicles plays an important role in ensuring road safety. Emergency message dissemination is usually carried out by broadcasting. However, high vehicle density and mobility lead to challenges in message dissemination such as broadcasting storm and low probability of packet reception. This paper proposes a federated learning based blockchain-assisted message dissemination solution. Similar to the incentive-based Proof-of-Work consensus in blockchain, vehicles compete to become a relay node (miner) by processing the proposed Proof-of-Federated-Learning (PoFL) consensus which is embedded in the smart contract of blockchain. Both theoretical and practical analysis of the proposed solution are provided. Specifically, the proposed blockchain based federated learning results in more vehicles uploading their models in a given time, which can potentially lead to a more accurate model in less time as compared to the same solution without using blockchain. It also outperforms other blockchain approaches in reducing 65.2% of time delay in consensus, improving at least 8.2% message delivery rate and preserving privacy of neighbor vehicle more efficiently. The economic model to incentivize vehicles participating in federated learning and message dissemination is further analyzed using Stackelberg game. The analysis of asymptotic complexity proves PoFL as the most scalable solution compared to other consensus algorithms in vehicular networks.

Blockchain-based random auditor committee for integrity verification

With the popularity of cloud storage, integrity verification for outsourced data has attracted more and more attention. The majority of existing research works rely on a unique third-party auditor (TPA) or fixed TPAs to audit the integrity of outsourced data, and thus they are vulnerable to DoS and collusion attacks as the TPA is not completely trusted. To conquer this problem, a blockchain-based random auditor committee is proposed to replace the fixed TPAs for the integrity verification (call BRAC scheme for short). The proposed blockchain consensus algorithm utilizes a verifiable random function (VRF) to select the third-party auditor committee (TPAC) which performs contract verification. The leader of TPAs (LTPA) packs the verification proof into a blockchain called verification chain. The main idea is employing the output of a VRF for leader election to make it probabilistic, such that specific nodes cannot be targeted in advance and a certain fraction of the nodes being malicious can be tolerated. We present rigorous security analysis to demonstrate the security of the proposed scheme. Meanwhile, the comprehensive performance evaluation shows that the proposed scheme improves the performance of data integrity verification effectively.

Research on Progress of Blockchain Consensus Algorithm: A Review on Recent Progress of Blockchain Consensus Algorithms

Blockchain technology can solve the problem of trust in the open network in a decentralized way. It has broad application prospects and has attracted extensive attention from academia and industry. The blockchain consensus algorithm ensures that the nodes in the chain reach consensus in the complex network environment, and the node status ultimately remains the same. The consensus algorithm is one of the core technologies of blockchain and plays a pivotal role in the research of blockchain technology. This article gives the basic concepts of the blockchain, summarizes the key technologies of the blockchain, especially focuses on the research of the blockchain consensus algorithm, expounds the general principles of the consensus process, and classifies the mainstream consensus algorithms. Then, focusing on the improvement of consensus algorithm performance, it reviews the research progress of consensus algorithms in detail, analyzes and compares the characteristics, suitable scenarios, and possible shortcomings of different consensus algorithms, and based on this, studies the future development trend of consensus algorithms for reference.

Blockchain, climate damage, and death: Policy interventions to reduce the carbon emissions, mortality, and net-zero implications of non-fungible tokens and Bitcoin

The art industry has commercialised and popularised non-fungible tokens (NFTs), with the volume and value of NFT transactions rapidly growing to US$ 10.7 billion in Q3 2021. The increase in NFT transactions has drawn the attention of the art market to the consequent carbon emissions resulting from verifying transactions in proof-of-work blockchains supporting NFT transactions. With CO2-related deaths attributable to NFT transactions, social pressure from the art market has helped to progress the switch away from the deliberately polluting proof-of-work blockchains to more sustainable consensus protocols.Nonetheless, many popular types of blockchain have resisted the pressure to decrease their environmental impact, including Bitcoin, whose attributed 2021 annual emissions will produce emissions responsible for around 19,000 future deaths. In response, recent global policy interventions have employed legal and fiscal tools to reduce the carbon impact of some or all types of blockchains. Linking the damage caused by proof-of-work blockchains to climate change and human mortality, this study examines the recent policy interventions designed to motivate a shift in blockchain consensus protocols and promote miners' energy efficiency to mitigate environmental damage. This article further explores available policy intervention options that are currently not utilised.

Delegated Proof of Secret Sharing: A Privacy-Preserving Consensus Protocol Based on Secure Multiparty Computation for IoT Environment

With the rapid advancement and wide application of blockchain technology, blockchain consensus protocols, which are the core part of blockchain systems, along with the privacy issues, have drawn much attention from researchers. A key aspect of privacy in the blockchain is the sensitive content of transactions in the permissionless blockchain. Meanwhile, some blockchain applications, such as cryptocurrencies, are based on low-efficiency and high-cost consensus protocols, which may not be practical and feasible for other blockchain applications. In this paper, we propose an efficient and privacy-preserving consensus protocol, called Delegated Proof of Secret Sharing (DPoSS), which is inspired by secure multiparty computation. Specifically, DPoSS first uses polynomial interpolation to select a dealer group from many nodes to maintain the consensus of the blockchain system, in which the dealers in the dealer group take turns to pack the new block. In addition, since the content of transactions is sensitive, our proposed design utilizes verifiable secret sharing to protect the privacy of transmission and defend against the malicious attacks. Extensive experiments show that the proposed consensus protocol achieves fairness during the process of reaching consensus.

Reputation-Driven Dynamic Node Consensus and Reliability Sharding Model in IoT Blockchain

The Internet of Things that links the cyber and physical worlds brings revolutionary changes to society, however, its security and efficiency problems have not been solved. The Consortium Blockchain + IoT is considered to be an effective solution. The IoT blockchain network’s demand for transaction processing speed is gradually increasing. The throughput problem of the blockchain needs to be solved urgently and the security problem of transaction processing that comes with it. To solve the above problems, this paper proposes a reputation-driven dynamic node security sharding consensus model (RDSCM) in the blockchain, which consists of two parts: a reputation-driven node to eliminate PBFT (RE-PBFT) and a reputation-driven node cross reconfiguration sharding scheme (NCRS). The RE-PBFT eliminates abnormal nodes in the consensus network and reduces the probability of abnormal nodes becoming master nodes. NCRS improves the blockchain throughput while ensuring sharding reliability. Finally, the experiment proves that RE-PBFT can identify abnormal nodes and remove them in a short time. NCRS can effectively guarantee the reliability of sharding, and the transaction processing efficiency has been greatly improved after sharding.

Queuing Theory of Improved Practical Byzantine Fault Tolerant Consensus

In recent years, the use of consensus mechanism to maintain the security of blockchain system has become a considerable concern of the community. Delegated proof of stake (DPoS) and practical Byzantine fault tolerant (PBFT) consensus mechanisms are key technologies in maintaining the security of blockchain system. First, this study proposes a consensus mechanism combining DPoS and PBFT, which can rapidly deal with malicious witness nodes and shorten the time of block verification. Second, the M/PH/1 queuing model is used to analyze the performance of the proposed consensus mechanism, and the performance of the improved practical Byzantine fault tolerant consensus mechanism is evaluated from steady-state conditions and key performance measure of the system. Third, the current study uses the theoretical method of open (Jackson) queuing network, combined with the blockchain consensus process, and provides theoretical analysis with special cases. Lastly, this research utilizes numerical examples to verify the computability of the theoretical results. The analytic method is expected to open a series of potentially promising research in queueing theory of blockchain systems.

MSTDB: A Hybrid Storage-Empowered Scalable Semantic Blockchain Database

Blockchain has been regarded as a trusted carrier for distributed data storage. With large volumes of valuable data stored on blockchain, data query has become a major requirement. However, the existing blockchains do not provide efficient query functionality because of their deep-rooted chain structure. Blockchain database is a new direction that constructs index on top of blockchain to provide rich query functionalities. The existing works are either insecure because the query process separates from the blockchain consensus, or inscalable because all the data needs to be stored in the block. In this paper, we propose a novel semantic blockchain database called MSTDB. We design a hybrid on/off chain blockchain storage architecture in which the majority of blockchain storage is offloaded to the off-chain storage and a novel index structure named Merkle Semantic Trie (MST) is designed to be a secure and semantic bridge between on- and off-chain. Based on MST, MSTDB provides a variety of semantic query functions including multi-keyword query, range query, Top-K query, and cross-chain query. To improve the performance further, we design some index compression and query preprocessing techniques for MSTDB. Extensive experiments demonstrate the effectiveness and efficiency of our blockchain database.

Intelligent Terminal Computation Offloading Method Based on the Incentive of Reputation Value

Existing researches that apply blockchain into computation offloading do not consider the enthusiasm of terminals to participate in computation offloading, the fairness of terminals to obtain bookkeeping right and the consensus mechanism that applicable to computation offloading between terminals. So, in this paper, a computation offloading method based on reputation value incentive is proposed, and the detailed workflow of this method is designed. In the workflow, a computation resource allocation method based on dynamic adjustment auction, a mining difficulty setting method based on intelligent terminal devices (ITDs) clustering and an improved POW consensus mechanism based on reputation value (RVPOW) are proposed to ensure the fairness of ITDs to obtain bookkeeping right and improve the enthusiasm of ITDs to participate in computation offloading and blockchain consensus. Simulation results show that the proposed computation offloading method can encourage ITDs to participate in computation offloading, and the RVPOW consensus mechanism can achieve fast consensus.

Function Virtualization Can Play a Great Role in Blockchain Consensus

Bitcoin introduced a cryptocurrency as a form of public ledger consequently that turned into a most popular security technology, Blockchain. Its integrated mining technology lies the key security mechanism. The system allows forming a pool mining group to solve a particular job and share their revenues to their CPU usage while one of them successfully mines a block. To mine a block, a cryptographic puzzle should be solved, which requires significant compute resources that cause huge energy consumption. On the other hand, recent statistics show that low computational energy-restricted Internet of Things (IoT) devices are increasing exponentially. Although it has low energy and limited computation power, it is large in quantity when it is integrated. So we focus on a stochastic geometry theory, which resolves the issue of block mining computation via utilizing multiple mobile IoT devices, given that these IoT devices are Computation Capable Nodes (CCNs). To further normalize this issue, we propose an efficient mathematical solution that uses smart coordination of Virtual Network Functions (VNFs) for IoT devices to enable their CPU usage efficiently. At the same time, the work and credit point distribution policy is smartly handled through virtual pool mining. The proposal renders Network Function Virtualization technology to configure VNF, and Service Function Chain technology is utilized to enable the network flow of such VNFs. New algorithms are presented to solve multiple issues like node discovery, computation offloading, and work credit point distribution. Our goal is to minimize energy consumption within the given time constraint. Implementation results show that although virtual functions for block mining require extensive computations in IoT devices, dividing computation work into small fractions called tasks embedded with VNF, and offloading them to nearby CCNs, tend to minimize the cost and energy consumption of individual shared miners. The overall mining process is proved efficient and faster.

Research on the Judicial Expertise of Electronic Evidence Based on Blockchain

Give full play to the advantages of blockchain technology, guarantee the consensus of public credit institutions with the help of hierarchical nodes, and form a judicial alliance chain, so that the public can participate in the data verification activities of electronic evidence in the form of organizations, promoting the socialization and development of judicial activities. By using the credible time-stamp evidence, the judicial block chain presents the extremely formidable application superiority, the node verification based on the block chain consensus mechanism, is helpful to form the block chain judicial system which has the extremely application prospect. Through the analysis of the practical application and application prospect of the judicial block chain, the author makes a complete analysis of the idea of the electronic evidence judicial appraisal based on the block chain.