Blockchain Consensus Research Articles

Blockchain Consensus Mechanism for Distributed Energy Transactions

In order to reduce the cost of grid dispatching and increase the transparency of energy transactions, the distributed energy transaction model based on blockchain is constructed. At the same time, in order to improve the high communication overhead and low throughput of the traditional PBFT algorithm in the consortium blockchain, an efficient Byzantine fault-tolerant consensus mechanism (DE-BFT) for the energy blockchain is designed. The algorithm improves from two aspect: node election and main chain consensus. In the stage of node election, the model uses a health score evaluation and a verifiable random function to improve the security and randomness of node selection. In the stage of main chain consensus, the efficient data consistency interaction protocol decreases the complexity of the communications between nodes, down to a constant term level from exponential one. The result shows that, compared with other consensus algorithm, the DE-BFT algorithm performs better in terms of consensus delay, communication overhead, throughput, and consensus node reliability.

Traceability model based on improved witness mechanism

Traceability system is one of the popular applications of graphic blockchains. However, there are centralisation problems and a long time for final consistency confirmation in the graphic blockchain. In addition, the blockchain system in the traceability application scenario has the problem of insufficient supervision. Therefore, a witness-based graphic blockchain consensus mechanism is proposed. In the consensus mechanism, a verifiable random function is used to screen the publishers of the unit; an SM2 threshold signature is used to sign the unit information to improve the non-repudiation of the traceability information uploaders to the unit information under the supervision of the witness. The improved consistency algorithm cancels the process of finding a stable main chain and makes relatively many nodes to participate in the consensus process. The experimental results show that the graphic blockchain using the improved witness mechanism can reduce the degree of centralisation, shorten the time for new units to reach consensus, and greatly ensure the security and scalability of the blockchain system.

A probabilistic Proof-of-Stake protocol with fast confirmation

Proof-of-Stake (PoS) protocol is one of the most promising blockchain consensus protocols in the permissionless setting. However, there is a general problem of slow confirmation in PoS protocol. To address the issue, a small-sized committee in PoS protocol is used to reduce the costs in terms of communication and computation, and accelerate confirmation. Following this idea, a committee-based PoS protocol called LaKSA (NDSS’2021) is proposed recently.In this paper, we present a balance attack on LaKSA, and show LaKSA cannot satisfy the liveness property even in the synchronous network. To ensure security and improve efficiency, we propose a self-healing probabilistic PoS protocol with a small-sized committee and a fast confirmation. Specifically, we propose a three-phase broadcast finality gadget and two compatible confirmation rules. The participants can invoke the three-phase broadcast periodically and commit a block according to different confirmation rules. By our approaches, on the one hand, we can prevent the PoS protocol from the balance attack and keep it committing new blocks over time. On the other hand, it empowers the protocol an ability of self-healing, by which nodes can commit a block as quickly as possible instead of waiting for a long time. Furthermore, we prove that our protocol can achieve the security properties of probabilistic safety and liveness. Finally, we conduct extensive experiments to evaluate the performance of the self-healing protocol. The experimental results show that, compared with LaKSA protocol, our protocol improves the commit rate by about 30% with a high throughput under a poor network condition.

Blockchain Consensus Mechanism Based on Quantum Teleportation

The consensus mechanism is the core secret of the blockchain network. However, the consensus mechanism of the classical blockchain is based on the classical cryptosystem, which is based on the problem of computational complexity. With the improvement of computing power, the security of this cryptosystem is being threatened. In addition, the consensus mechanism of classic blockchain also has the following disadvantages: serious waste of computing resources and energy; the inability to withstand a 51% attack; low system throughput and large delay. Based on quantum teleportation technology and the randomness of quantum measurement, a consensus mechanism for a quantum blockchain system is proposed. Based on the physical properties of quantum mechanics, this scheme has the unconditional security of quantum cryptography. This new consensus mechanism does not involve a great deal of computing resources and hence has a lower energy consumption, shorter time delay and higher throughput. Furthermore, the new consensus mechanism could withstand a 51% attack.

A public blockchain consensus mechanism for fault-tolerant distributed computing in LEO satellite communications

In LEO (Low Earth Orbit) satellite communication systems, the satellite network is made up of a large number of satellites, the dynamically changing network environment affects the results of distributed computing. In order to improve the fault tolerance rate, a novel public blockchain consensus mechanism that applies a distributed computing architecture in a public network is proposed. Redundant calculation of blockchain ensures the credibility of the results; and the transactions with calculation results of a task are stored distributed in sequence in Directed Acyclic Graphs (DAG). The transactions issued by nodes are connected to form a net. The net can quickly provide node reputation evaluation that does not rely on third parties. Simulations show that our proposed blockchain has the following advantages: 1. The task processing speed of the blockchain can be close to that of the fastest node in the entire blockchain; 2. When the tasks' arrival time intervals and demanded working nodes(WNs) meet certain conditions, the network can tolerate more than 50% of malicious devices; 3. No matter the number of nodes in the blockchain is increased or reduced, the network can keep robustness by adjusting the task's arrival time interval and demanded WNs.

Critical Review of Blockchain Consensus Algorithms: challenges and opportunities

Blockchain is a distributed ledger in which transactions are grouped in blocks linked by hash pointers. Blockchain-based solutions provide trust and privacy because of the resistance to the inconsistency of data and advanced cryptographic features. In various fields, blockchain technology has been implemented to ensure transparency, verifiability, interoperability, governance, and management of information systems. Processing large volumes of data being generated through emerging technologies is a big issue. Many researchers have used Blockchain in various fields integrated with IoT, i.e., industry 4.0, biomedical, health, genomics, etc. Blockchain has the attributes of decentralization, solidness, security, and immutability with a possibility to secure the system design for transmission and storage of data. The purpose of the consensus protocols is to keep up the security and effectiveness of the blockchain network. Utilizing the correct protocol enhances the performance of the blockchain applications. This article presents essential principles and attributes of consensus algorithms to show the applications, challenges, and opportunities of blockchain technology. Moreover, future research directions are also presented to choose an appropriate consensus algorithm to enhance the performance of Blockchain based applications

Proof of Learning: Towards a Practical Blockchain Consensus Mechanism Using Directed Guiding Gradients (Student Abstract)

Since Bitcoin, blockchain has attracted the attention of researchers. The consensus mechanism at the center of blockchain is often criticized for wasting a large amount of computing power for meaningless hashing. At the same time, state-of-the-art models in deep learning require increasing computing power to be trained. Proof of Learning (PoL) is dedicated to using the originally wasted computing power to train neural networks. Most of the previous PoL consensus mechanisms are based on two methods, recomputation or performance metrics. However, in practical scenarios, these methods both do not satisfy all properties necessary to build a large-scale blockchain, such as certainty, constant verification, therefore are still far away from being practical. In this paper, we observe that the opacity of deep learning models is similar to the pre-image resistance of hash functions and can naturally be used to build PoL. Based on our observation, we propose a method called Directed Guiding Gradient. Using this method, our proposed PoL consensus mechanism has a similar structure to the widely used Proof of Work (PoW), allowing us to build practical blockchain on it and train neutral networks simultaneously. In experiments, we build a blockchain on top of our proposed PoL consensus mechanism and results show that our PoL works well.

Editable and Verifiable Anonymous Authentication Incorporating Blockchain in the Internet of Energy

With the continuous development of the Internet of Energy, the access of a large number of distributed renewable energy has caused difficulties in energy management. The traditional energy management mode cannot meet the needs of existing energy management and trading. Therefore, this paper proposes an integrated energy management platform based on blockchain, which allows multiple decentralized energy management systems to conduct unified identity authentication. At the same time, an editable and verifiable anonymous authentication (EVAA) scheme integrating blockchain in the Internet of Energy is designed, which combines the idea of chameleon hash (CH) and the algorithm of elliptic curve encryption (ECC) to realize the dual identity authentication of user information. Finally, the generated certificate is stored in the chain through blockchain consensus. The scheme is mainly constructed using multiple secure cryptographic algorithms, which combine the advantages of blockchain for information authentication. Thus, it can accomplish user cross-system authentication and transaction, and achieve more secure editable anonymous identity authentication through the algorithm performance test, compared with the existing similar schemes under the unified test standard. This paper not only ensures the operation efficiency, but also reflects the obvious advantage of realizing higher intensity security performance.

Optimization of PBFT Algorithm Based on QoS-Aware Trust Service Evaluation

In service-transaction scenarios, blockchain technology is widely used as an effective tool for establishing trust between service providers and consumers. The consensus algorithm is the core technology of blockchain. However, existing consensus algorithms, such as the practical Byzantine fault tolerance (PBFT) algorithm, still suffer from high resource consumption and latency. To solve this problem, in this study, we propose an improved PBFT blockchain consensus algorithm based on quality of service (QoS)-aware trust service evaluation for secure and efficient service transactions. The proposed algorithm, called the QoS-aware trust practical Byzantine fault tolerance (QTPBFT) algorithm, efficiently achieves consensus, significantly reduces resource consumption, and enhances consensus efficiency. QTPBFT incorporates a QoS-aware trust service global evaluation mechanism that implements service reliability ranking by conducting a dynamic evaluation according to the real-time performance of the services. To reduce the traffic of the blockchain, it uses a mechanism that selects nodes with higher values to form a consensus group that votes for consensus according to the global evaluation result of the trust service. A practical protocol is also constructed for the proposed algorithm. The results of extensive simulations and comparison with other schemes verify the efficacy and efficiency of the proposed scheme.

PROACT: Parallel multi-miner proof of accumulated trust protocol for Internet of Drones

Several types of networks that comprise unmanned aerial vehicles (UAV or drone) are being utilized in important applications such as emergency response, environment and infrastructure monitoring, defense and security, and commerce. In such networks, swarms of UAVs cooperate in executing one or more missions to achieve the application's objectives. The UAVs communicate with terrestrial networks by connecting to fixed or mobile ground control stations (GCS). The ability of drones to connect to online applications and offer services to Internet users has led to the proliferation of the Internet of Drones (IoD). However, IoD applications are highly vulnerable to many types of cyberattacks. Hence, mechanisms must be deployed to secure the IoD operations and data. Recently, the blockchain has been proposed as a solution to detect and prevent malicious attacks on the UAV network (UAVN). Due to the UAV's limited resources, it becomes a challenge to integrate the blockchain into the IoD. In this paper, we propose a model that enables a drone to store the important data that it requires during its flight within a lightweight blockchain system. In addition, we propose a new blockchain consensus mechanism in which several miners produce their blocks in parallel, which decreases the time needed to add transactions securely to the blockchain and meets the requirements of delay-sensitive applications. Our simulations prove the advantages of the proposed model in decreasing the transaction-to-blockchain delay, the average drone energy consumption, and the blockchain block size as compared to other IoD blockchain systems.

The Block Propagation in Blockchain-Based Vehicular Networks

Consensus is one of the most important issues of a blockchain system because it is a necessary process to reach an agreement between a group of separated nodes that do not trust each other in a decentralized framework. Most existing blockchain consensus works assume that the time of block propagation among separated nodes during the consensus process is ignorable, i.e., a block always successfully reaches every participating node during a period of time that is far shorter than the mining time. However, when blockchain is used in vehicular <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ad hoc</i> networks (VANETs), the block propagation time is no longer negligible since the dynamic connectivity of the moving nodes in a wireless environment brings opportunistic communication to blockchain consensus. In this article, we study the impact of mobility on block propagation under the single-chain structure in VANET. Specifically, we investigate the dynamics of block propagation from the macroscopic view and derive the closed-form expression of the single-block propagation time. Then, we characterize the blockchain forking as the multiblock competitive propagation. In this way, an approximate result on multiblock propagation time is discussed. An interesting finding is that higher mobility and more moving vehicles can speed up the block propagation. In addition, we also discover that distinct propagation capabilities of moving nodes contribute to the forking reduction in the blockchain consensus.

Survey on Blockchain Consensus Algorithms and Application

Survey on Blockchain Consensus Algorithms and Application

A blockchain consensus mechanism that uses Proof of Solution to optimize energy dispatch and trading

A blockchain consensus mechanism that uses Proof of Solution to optimize energy dispatch and trading

A Proof-of-Transactions Blockchain Consensus Protocol for Large-Scale IoT

Blockchain technology can benefit Internet of Things (IoT) in terms of message exchange, access control and management, however, existing blockchain consensus protocols cannot provide sufficient performance without compromising security and fairness. This paper proposes a round-based two-stage blockchain consensus protocol called Proof-of-Transactions (PoT) for a variety of requirements such as performance and security of large-scale IoT. In the first stage of each round, all nodes pre-construct new blocks and exchange information about the number of valid transactions contained in each other’s blocks. The block containing most valid transactions is broadcasted in the second stage and examined by all nodes of the cluster before being received as the new block in the global blockchain ledger. The consensus reaching of a new block requires only two rounds of message exchange process. Theoretical analysis and experimental results verify the feasibility and superiority of the proposed protocol.

Blockchain in energy systems: From centralized to decentralized

The increasingly distributed energy system poses a serious challenge to traditional centralized management schemes. Blockchain is a promising technique for enabling trusted collaboration without a trusted central authority. Still, blockchains are limited to being applied in the energy system as they are not specialized for mathematical optimization. To fill this gap, Chen et al. propose a blockchain consensus mechanism (proof of solution, PoSo) tailored to support mathematical optimization problems in energy systems, which replaces the meaningless mathematical puzzle in proof of work (PoW) with a meaningful optimization problem. The inspiration comes from the fact that both the solutions to the puzzle and to an optimization problem are hard to find but easy to verify.

A DAG Blockchain-Enhanced User-Autonomy Spectrum Sharing Framework for 6G-Enabled IoT

The rapidly growing number of Internet-of-Things (IoT) devices poses new challenges for spectrum management in future wireless communication networks. It is critical to achieve efficient and dynamic spectrum management in the sixth-generation (6G) wireless communication networks era. To tackle the challenges of managing a large-scale IoT network with heterogeneous devices, we propose a directed acyclic graph (DAG) blockchain-enhanced user-autonomy spectrum sharing model. As the proposed consensus rule is closely related to system utility, the swarm intelligence of users gradually reaches the point of convergence in the process of blockchain consensus. We analyze the effect of the tip selection method of the DAG blockchain on spectrum allocation utility. A dynamic tip selection method is proposed to enhance the global utility, which is related to the spectrum supply–demand. In addition, the ring signature technique is utilized to realize privacy protection during the sharing process. Simulation indicates that the proposed tip selection method achieves a 10% enhancement in terms of the global utility. Furthermore, significant reductions in administrative expense and reliability improvement are demonstrated by simulation results. The stability of the tip number in the proposed model has been proved theoretically, which is also validated by simulation experiments.

A MCDM-based framework for blockchain consensus protocol selection

Blockchain is one of the most disruptive technologies introduced in Bitcoin, which engaged great attention from the industry and academia and determined a rapid growth of other Distributed Ledger Technologies (DLTs). In the complex architecture of a DLT system, a consensus protocol plays a key role by ensuring that all participants agree on the data integrity without any central authority. A wide range of consensus protocols have been designed with different concepts and properties (e.g., lower energy consumption, better scalability, smaller latency, higher throughput, etc.). The key requirements for consensus protocols passing from one blockchain system to another often differ significantly, and there is no one-fit-all protocol. Therefore, selecting the most suitable consensus protocol for a particular DLT system is essential, but at the same time a challenging step, as decision-makers need to make a trade-off between conflicting requirements. This paper introduces a framework for selecting the most suitable consensus protocols depending on the identified criteria, priorities, and other requirements by incorporating Multi-Criteria Decision-Making (MCDM) techniques. We demonstrate its potential by identifying the preferable consensuses for the three most common types of existing blockchain systems and on an actual application for bike renting. Moreover, the collected data and tools are freely available, ensuring full replicability, reusability, and further development.

A Random and Scalable Blockchain Consensus Mechanism

The central piece of blockchain technologies is the consensus algorithm. The consensus is reached via consensus algorithms in the distributed network of the blockchain. The consensus becomes stronger if nearly all the nodes in the blockchain network take part in building the blockchain. Even if some nodes misbehave or malfunction, the consensus should not break down then. Since blockchain networks are distributed, even if some regions of the network or some nodes of the network leave, the blockchain network should not malfunction and it should be consistent. Therefore, the consistency of the blockchain transactions should be assured by all the nodes or nearly all the nodes, or most of the nodes. In other words, the consensus should be the issue of all the nodes. In this work, a novel consensus algorithm is presented to diffuse the mission of building the blockchain to all the nodes. In other words, the consensus should be the issue of all the nodes. In this work, a novel consensus algorithm is presented to diffuse the mission of building the blockchain to all the nodes. The algorithm increases the randomness of nodes and enforces the blockchain network to be more decentralized. Randomness is realized by employing the power of cryptography, especially by using public keys as a characteristic for miners, which are also called signers. Moreover, since the algorithm is realized with a few operations, it contributes to the scalability of the blockchain. Furthermore, digital signatures improve the security level and consistency of the blockchain.

Trusted Blockchain-Driven IoT Security Consensus Mechanism

Single point of failure and node attack tend to cause instability in the centralized Internet of Things (IoT). Combined with blockchain technology, the deficiency of traditional IoT architecture can be effectively alleviated. However, the existing blockchain consensus mechanism still has the problems of forks and wasting of computing power. Therefore, this paper proposes a new framework based on a two-stage credit calculation to handle these problems. Notably, the nodes are selected through the model, and these nodes will compete on the chain according to the behavior of participating in the creation of the block. Then, a comparative simulation with the existing consensus mechanism proof of work (PoW) is presented. The results show that the proposed framework can quickly eliminate malicious nodes, maintain the overall security of the blockchain and reduce consensus delay.

A Novel Consensus Algorithm Based on Segmented DAG and BP Neural Network for Consortium Blockchain

Currently, because of the excellent properties of decentralization, hard tamperability, and traceability, blockchain is widely used in WSN and IoT applications. In particular, consortium blockchain plays a fundamental role in the practical application environment, but consensus algorithm is always a key constraint. Over the past decade, we have been witnessing the obvious growth in blockchain consensus algorithms. However, in the existing consortium blockchain consensus algorithms, there is a limited characteristic of scalability, concurrency, and security. To address this problem, this work introduces a new consensus algorithm that is derived from a directed acyclic graph and backpropagation neural network. First, we propose a partitioned structure and segmented directed acyclic graph as data storage structure, which allows us to improve scalability, throughput, and fine-grained granularity of transaction data. Furthermore, in order to provide the accuracy of node credit evaluation and reduce the possibility of Byzantine nodes, we introduce a novel credit evaluation mechanism based on a backpropagation neural network. Finally, we design a resistant double-spending mechanism based on MapReduce, which ensures the transaction data are globally unique and ordered. Experimental results and security analysis demonstrate that the proposed algorithm has advantages in throughput. Compared with the existing methods, it has higher security and scalability.