At present, the number of incoming devices and mobile data traffic has seen explosive growth, and spectrum resources are difficult to meet the increasing demand. The traditional centralized spectrum management model suffers from low spectrum utilization, high maintenance costs, and data security issues. The decentralized and secure nature of blockchain technology is a natural advantage in solving the problems faced by the current spectrum management model. However, when introducing traditional blockchain technology into spectrum management, it faces problems such as high latency and high resource consumption. In this letter, we design a new blockchain-enabled spectrum trading framework consisting of the access layer, distribution layer, and core layer, and then propose a user benefit-maximum spectrum trading matching scheme. To solve the problem of latency and energy consumption of consensus algorithms in blockchains, the dynamic credit aggregate-signature Byzantine fault tolerance (DCABFT) algorithm based on the Boneh-Lynn-Shacham (BLS) aggregated signature is proposed. Simulation results demonstrate that the proposed scheme can greatly improve the transaction latency and users’ quality of service.
Sharding technology is a promising solution for improving the scalability of blockchain systems. However, it faces the problem of allocating suitable trusted nodes into separate shards to satisfy security and efficiency requirements. Existing blockchain sharding methods fail to consider shard trust difference, communication latency difference, and node count difference among shards. This tends to increase the risk of a blockchain failure. This work proposes a novel blockchain sharding model for node allocation by considering shard trust difference. Its key idea is to allocate nodes of different trust levels to suitable shards to make shards have almost the same trust, such that shards’ reliability increases and blockchain failure probability decreases. To reduce the communication delay among shards, this work considers the communication latency difference and node count difference among shards. It proposes a sharding algorithm to iteratively adjust node allocations such that an optimal or near-optimal node allocation set is obtained. Simulation results show that the proposed method can effectively improve shard security and the performance of blockchain sharding compared with two state-of-the-art methods, i.e., Monoxide and Rapidchain, in terms of throughput, latency, and blockchain failure probability.
Hyperledger Fabric is a popular permissioned blockchain system that features a highly modular and extensible system for deploying permissioned blockchains which are expected to have a major effect on a wide range of sectors. Unlike traditional blockchain systems such as Bitcoin and Ethereum, Hyperledger Fabric uses the EOV model for transaction processing: the submitted transactions are executed by the endorsing peer, ordered and batched by the ordering services, and validated by the validating peers. Due to this EOV workflow, a well-documented issue that arises is the multi-version concurrency control conflict. This happens when two transactions try to writes and read the same key in the ledger at the same time. Existing solutions to address this problem includes eliminating blocks in favor of streaming transactions, repairing conflicts during the ordering phase, and automatically merging the conflicting transactions using CRDT (Conflict Free Replicated Data) techniques. In this paper, we propose a novel solution called Early Detection for MVCC Conflicts. Our solution detects the conflicting transactions at an early stage of the transaction execution instead of processing them until the validation phase to be aborted. The advantage of our solution is that it detects conflict as soon as possible to minimize the overhead of conflicting transaction on the network resulting in the reduction of the end-to-end transaction latency and the increase of the system's effective throughput. We have successfully implemented our solution in Hyperledger Fabric. We propose three different implementations which realize early detection. Our results show that our solutions all perform better than the baseline Fabric, with our best solution SyncMap which improves the goodput by up to 23% and reduces the latency by up to 80%.
József Udvaros, Norbert Forman, Szilárd Mihály Avornicului
We present a solution based on blockchain technology and smart contracts for agile project management in light of the continuing transition in the software development industry. Due to the fact that these technologies are self-executing, customized, and impervious to tampering, they are considered to be crucial for the transition to a more efficient, transparent, and transactive payment gateway between major stakeholders. These major stakeholders will be able to communicate through smart contracts, which will act as a bridge between them. As part of their responsibility, they will make sure that all of the terms of the contract are met and acknowledged by all members of the team. As a result of our research, we propose a model in which payouts could be automatically enabled and penalties or grants could be introduced based on performance. If any changes were to be made to the contract in the future, all parties involved would be automatically notified. To maintain the development cycle, they should accept these changes as soon as possible. Because of this, the product owner and client are able to concentrate their resources on more profitable and productive tasks, without the need to monitor this aspect of agile project management. Our proposed model brings together different partners with the objective of successfully developing different IT projects by leveraging software engineering solutions such as smart contracts.
Majed Abdullah Alrowaily, Mansoor Alghamdi, Ibrahim S. Alkhazi, Ahmad B. Hassanat · 6 authors
Blockchain technology has a wide range of applicability in the fields of transportation infrastructure construction and maintenance, transportation big data analysis and application, expressway toll collection, and logistics. The core technology lies in the distributed, decentralized, immutable, and programmable features brought about by consensus. This paper studies the dynamic analytical modeling of Proof-Based Consensus (PBC) strategies in blockchain systems, focusing on basic strategies, including Proof of Work (PoW), Proof of Stake (PoS), Proof of Authority (PoA), and Proof of Luck (PoL), which can be extended to other PBC models. We focus on modeling these typical strategies and discuss their solution characteristics in terms of algorithmic mechanisms and principles. The relevant results can be used for quantitative analysis and evaluation of distributed consensus based on the model.
Aside from the conception of new blockchain architectures, existing blockchain optimizations in the literature primarily focus on system or data-oriented optimizations within prevailing blockchains. However, since blockchains handle multiple aspects ranging from organizational governance to smart contract design, a holistic approach that encompasses all the different layers of a given blockchain system is required to ensure that all optimization opportunities are taken into consideration. In this vein, we define a multi-level optimization recommendation approach that identifies optimization opportunities within a blockchain at the system, data, and user level. Multiple metrics and attributes are derived from a blockchain log and nine optimization recommendations are formalized. We implement an automated optimization recommendation tool, BlockOptR, based on these concepts. The system is extensively evaluated with a wide range of workloads covering multiple real-world scenarios. After implementing the recommended optimizations, we observe an average of 20% improvement in the success rate of transactions and an average of 40% improvement in latency.
André Augusto, Rafael Belchior, Imre Kocsis, Gönczy László · 6 authors
The last few years have seen a steep increase in blockchain interoperability research. Most solutions connect public blockchains; hence, the main cross-chain use case is token transfer. By-design platform transparency, tamper-resistance, and auditability make blockchains an infrastructure candidate for Central Bank Digital Currencies (CBDCs), but bridging CBDCs is an important missing piece in general. In this paper, we leverage an asset transfer protocol, ODAP/SATP, to define an extendable and dependable blockchain interoperability middleware that can bridge CBDC from Hyperledger Fabric to EVM-based permissioned blockchains. The key interoperation enabler in the solution is a shared asset definition enforced by both sides of the bridge, accompanied by a mapping between Fabric Identities and Ethereum addresses for Identity management. We implement our design for the CBDC use case utilizing Hyperledger Cactus. Through a preliminary performance evaluation, we show that the underlying ledgers heavily influence the latency of the solution, not the bridging components.
Blockchain presents many new examples of delivering a robust audit trail using the distributed ledger. However, some potential issues, especially scalability and privacy, are still ongoing in the blockchain. Fortunately, these issues can be settled by using cloud computing. Cloud computing is an on-demand service that enables consumers to purchase and use IT resources. It saves the consumer's cost as consumers don't have to spend extra on building their on-premises server and providing extra security to the application. Enterprises interested in joining the blockchain flow can run their blockchain in the cloud. Cloud Service Providers (CSPs) provide multiple services such as IaaS, PaaS, SaaS and BaaS that can help a business start its blockchain application. But there are still risks that should be carefully noted. Data leaks and breaching are still possible despite the safety and privacy guarantees. The failure to achieve proper security will have to face massive potential fines. In this research, the authors addressed the impact of utilising the cloud in the blockchain and provided an in-depth understanding of the relationship between blockchain technology and cloud computing.
With the rapid growth of Industrial Internet of Things (IIoT) devices, managing an extensive volume of IIoT data becomes a significant challenge. While the conventional cloud storage approaches with centralized data centers suffer from high latency for large-scale IIoT data storage due to increased communication and latency overheads, distributed storage frameworks, such as blockchains, have become promising solutions. In this article, we design and analyze a dual-blockchain framework for secure and scalable distributed data management in large-scale IIoT networks. The proposed framework, namedMapChain-D, consists of a data chain that is mapped to an index chain to provide efficient data storage and lookup.MapChain-Dis designed for practical IIoT applications with storage, latency, and communication constraints. Detailed data exchange protocols are presented for data insertion and retrieval operations inMapChain-D. Based on these, theoretical analyses are provided on the space, time, and communication complexities ofMapChain-Dcompared with conventional single-chain frameworks with local and distributed data storage. We implement ourMapChain-Dprototype using open-source LoRaWAN communications with multiple Raspberry Pi and Arduino devices, Kademlia-based distributed hash table, and Ethereum-based blockchain with proof-of-authority consensus. Experimental results from our prototype show thatMapChain-Dis more suitable to be deployed on resource-constrained IIoT devices. We also highlight the scalability and flexibility ofMapChain-Dwith different number of edge nodes in the system.
Ye Lu, Caihua Liu, Meng Zhao, Xiaodong Duo · 7 authors
Transaction throughput is an important indicator of blockchain performance. However, many current smart contract virtual machines have low efficiency in executing smart contract transactions, which results in low transaction throughput of the blockchain. Some transaction parallel execution approaches have effectively improved transaction execution efficiency, but there are still problems such as low parallelism and large-scale transaction rollbacks. Therefore, we propose FSC, a fast execution approach for smart contract transactions based on fine-grained read-write analysis. The key idea is to obtain fine-grained read-write information from the smart contract compiler, and use this read-write information to group transactions at the blockchain platform layer, thereby improving the parallelism of transaction execution. FSC mainly includes three parts of work: 1) a fine-grained analysis method for read-write information at the contract state variable level based on the contract compiler; 2) a series of merging rules for merging read-write items; 3) a method to handle conflicting transactions. Our evaluation results show that FSC can accelerate the execution of smart contract transactions. Compared with before, FSC can reduce the overall transaction execution latency by 58.1%. In addition, FSC can shorten the longest execution path by 89.9% when the variation in transaction grouping latency is within 5.5%.
In the healthcare industry, software quality plays a crucial role as it is used in almost all systems used for medical intervention. If the quality of healthcare software is not considered, it can potentially have a negative effect and may create catastrophic situations for the patient’s health and can seriously affect the organisation’s reputation. Maintainability is a key component of software quality, making up 80% of the total cost of the software development life cycle cost. Software maintainability can be assessed using metrics that are stored in a centralised location. Software maintainability metrics and related data are crucial. If attackers alter this data, it affects the overall quality of healthcare software. In order to solve this issue, we adapted blockchain-based storage, which offers the advantages of decentralisation, immutability, and transparency and is a promising solution. We used Storj, a blockchain-based decentralised file system, to secure the maintainability metrics and related data. According to the results, the maintainability metrics data stored in the blockchain-based decentralised file storage is more secure, redundant, and cost-effective than centralised storage.
Blockchain is described as a cacheable, immutable that makes tracking transactions and assets in a corporate network easier. Hyperledger is a free software initiative that was designed to aid in the development of distributed ledgers based on blockchain technology. Hyperledger has several frameworks, including Hyperledger Fabric, Hyperledger Burrow, Hyperledger Indy, Hyperledger Sawtooth, and Hyperledger Grid. There are also other Hyperledger-based technologies used in blockchain. This research paper investigates the many applications and strategies employed by the Hyperledger Fabric blockchain network. There will also be a discussion regarding Hyperledger frameworks, future improvements, and overall applications used.
Social media's decentralization gives users control of their data, contributing to privacy, ownership, and dissemination. The challenge is to develop a decentralized social media platform with the same features and performances as its centralized counterpart. This study aims to demonstrate and evaluate the performance of decentralized social media in terms of throughput and scalability. The prototype application is developed on NEAR (Near Protocol Blockchain), a non-EVM (Ethereum Virtual Machine) chain with sharding. The results show that the use of NEAR to store post content is not a scalable solution, and the workaround of using IndexedDB as a local database to store information reduces response time and increases throughput and scalability. Collaboration of on-chain and off-chain storage strategies performs better for decentralized social media applications.
Blockchain is a decentralized ledger that serves as the foundation of Bitcoin and has found applications in various domains due to its immutable properties. It has the potential to change digital transactions drastically. It has been successfully used across multiple fields for record immutability and reliability. The consensus mechanism is the backbone of blockchain operations and validates newly generated blocks before they are added. To verify transactions in the ledger, various peer-to-peer (P2P) network validators use different consensus algorithms to solve the reliability problem in a network with unreliable nodes. The security and reliability of the inherent consensus algorithm used mainly determine blockchain security. However, consensus algorithms consume significant resources for validating new nodes. Therefore the safety and reliability of a blockchain system is based on the consensus mechanism's reliability and performance. Although various consensus mechanisms/algorithms exist, there is no unified evaluation criterion to evaluate them. Evaluating the consensus algorithm will explain system reliability and provide a mechanism for choosing the best consensus mechanism for a defined set of problems. This article comprehensively analyzes existing and recent consensus algorithms' throughput, scalability, latency, energy efficiency, and other factors such as attacks, Byzantine fault tolerance, adversary tolerance, and decentralization levels. The paper defines consensus mechanism criteria, evaluates available consensus algorithms based on them, and presents their advantages and disadvantages.
Mohammad Alshinwan, Ahmed Younes Shdefat, Nour Mostafa, Abdullah A.M AlSokkar · 6 authors
Blockchain technology is one of the crypto-currency technologies that has received a lot of attention. It has also found use in various applications, including the Internet of Things (IoT) and Cloud computing. Nonetheless, Blockchain has a significant scalability issue, restricting its ability to support services with various transactions. On the other hand, cloud computing is the on-demand availability of shared computer system resources, although issues now beset it in automation, processes, management, policies, and human aspects. Combining cloud computing and blockchain technology into a single system can improve network control, task scheduling, data integrity, resource management, pricing, fair payment, and resource allocation. In this article, we offered a comprehensive and up-to-date survey of cloud computing and Blockchain integration, a critical service for business applications due to the benefits of privacy, security, and service support. The lack of a comprehensive assessment examining the significance of BaaS platforms used in cloud computing prompted this review. We focus on the various BaaS tools that are currently in use. This report also examines the most common BaaS platforms incorporating Blockchain as a cloud service, such as Alibaba, Oracle, Azure, Amazon, and IBM. Furthermore, this research highlighted some major technological issues associated with merging Blockchain with cloud computing.
Blockchain consensus protocols are responsible for coordinating the nodes to make agreements on the transaction results. Their implementation bugs, including memory-related and consensus logic vulnerabilities, may pose serious threats. Fuzzing is a promising technique for protocol vulnerability detection. However, existing fuzzers cannot deal with complex consensus states of distributed nodes, thus generating a large number of useless packets, inhibiting their effectiveness in reaching the deep logic of consensus protocols.
Asmaa Aldoubaee, Noor Hafizah Hassan, Fiza Abdul Rahim
Blockchain is an exciting new technology that has garnered attention across multiple industries. This new technology offers several advantages, including decentralization, transparency, and immutability. However, several issues limit the effectiveness of this technology, such as scalability, interoperability, and privacy. A systematic review of blockchain scalability research was conducted using three primary databases: ACM, Science Direct, and IEEE. The review examined the state of the art in blockchain scalability, identifying the most important research trends and challenges. The solutions that have been established can be categorized into two main groups: those that pertain to block storage and those that pertain to the underlying blockchain mechanism. Numerous solutions were suggested for each main group. The most common proposed solutions for improving the scalability of blockchain networks in the literature are improving the consensus algorithm and using sharding. Most of the solutions were proof of concept and need more investigation in the future.