Luc Gerrits, Cyril Naves Samuel, Roland Kromes, François Verdier · 6 authors
Private or consortium blockchain networks have fewer verified participants and offer better throughput and transaction efficiency than public networks. However, as more and more blockchain consensuses are designed for private or consortium networks, their performances are often estimated without a practical use case implementation. In our use case, participants do not have to trust each other but still work together to build an ecosystem where users control their data and information. This paper analyzes the performance (transaction throughput, rejections, node participants) of Byzantine Fault Tolerant Consensus (BFT) using two blockchains: Hyperledger Sawtooth and Ethereum.
Befekadu G. Gebraselase, Bjarne E. Helvik, Yuming Jiang
Blockchain is a technology that provides a distributed ledger that stores previous records while maintaining consistency and security. Bitcoin is the first and largest decentralized electronic cryptographic system that uses blockchain technology. It faces a challenge in making all the nodes synchronize and have the same overall view with the cost of scalability and performance. In addition, with miners' financial interest playing a significant role in choosing transactions from the backlog, small fee or small fee per byte value transactions will exhibit more delays. To study the issues related to the system's performance, we developed an $M(t)/M^N/1$ model. The backlog's arrival follows an inhomogeneous Poison process to the system that has infinite buffer capacity, and the service time is distributed exponentially, which removes $N$ transactions at time. Besides validating the model with measurement data, we have used the model to study the reward distribution when miners take transaction selection strategies like fee per byte, fee-based, and FIFO. The analysis shows that smaller fee transactions exhibit higher waiting times, even with increasing the block size. Moreover, the miner transaction selection strategy impacts the final gain.
Muhammad Milhan Afzal Khan, Hafiz Muhammad Azeem Sarwar, Muhammad Awais
Abstract In Ethereum blockchain, whenever a transaction of smart contract is executed, transaction fee is charged in terms of Ethers. To calculate the transaction fee, a computational unit, gas is introduced in smart contracts. Gas consumption is calculated against the smart contract source code execution. The transaction initiator sets the gas price against per unit of gas and the total gas limit. If the gas limit is sufficient, the transaction will be mined otherwise it will be reverted. Smart contracts of Ethereum can be written in any high‐level language such as Solidity, Vyper, Python, Java and so forth, but Solidity is massively used for smart contracts creation. In this article, we have examined the 5000 transactions of Solidity based smart contracts from Etherscan and performed statistical analysis on opcodes and source code parameters used in these transactions to identify gas costly patterns. Our statistical results (correlation and regression) analyze the relationship of Solidity parameters and opcodes with the gas consumption. Factors causing an increase or decrease in the gas consumption of smart contracts are highlighted in this article. The regression analysis showed that 87.8% of the variability in the response variable (gas consumption) is due to the parameters used in this analysis. Our results will help the smart contract developers to write the gas optimized smart contracts. The results can be beneficial for end users as they will have to pay gas price for less number of gas units.
Fernando Richter Vidal, Naghmeh Ivaki, Nuno Laranjeiro
Nowadays, blockchain has been adopted by applications that are beyond cryptocurrencies. In such applications, the data generated or transactions executed are likely to be altered (revoked) due to several reasons, including business requests, legislation, or the existence of bugs. In addition, most of the data are being created by smart contracts, which, in many cases, are built by developers with non-sophisticated development tools or lacking expertise, leading to code holding residual bugs. In blockchain systems, in which immutability is one of the most critical characteristics, implementing reliable, secure, and efficient (i.e., in terms of time) revocation is a difficult challenge. This paper reviews 8 revocation mechanisms identified in current literature and discusses the applicability of each solution and associated challenges. We expect that our analysis contributes to the definition of new or improved mechanisms for transaction and data revocation in blockchain systems.
Blockchain technology has been recognized as a promising solution to enhance the security and privacy of Internet of Things (IoT) and Edge Computing scenarios. Taking advantage of the Proof-of-Work (PoW) consensus protocol, which solves a computation intensive hashing puzzle, Blockchain assures the security of the system by establishing a digital ledger. However, the computation intensive PoW favors members possessing more computing power. In the IoT paradigm, fairness in the highly heterogeneous network edge environments must consider devices with various constraints on computation power. Inspired by the advanced features of Digital Twins (DT), an emerging concept that mirrors the lifespan and operational characteristics of physical objects, we propose a novel Miner-Twins (MinT) architecture to enable a fair PoW consensus mechanism for blockchains in IoT environments. MinT adopts an edge-fog-cloud hierarchy. All physical miners of the blockchain are deployed as microservices on distributed edge devices, while fog/cloud servers maintain digital twins that periodically update miners’ running status. By timely monitoring miner’s footage that is mirrored by twins, a lightweight Singular Spectrum Analysis (SSA) based detection achieves to identify individual misbehaved miners that violate fair mining. Moreover, we also design a novel Proof-of-Behavior (PoB) consensus algorithm to detect byzantine miners that collude to compromise a fair mining network. A preliminary study is conducted on a proof-of-concept prototype implementation, and experimental evaluation shows the feasibility and effectiveness of proposed MinT scheme under a distributed byzantine network environment.
Ethereum, that enable development of decentralized applications, will likely to leverage cloud computing. In this research, we evaluate the performance of a cloud-based Ethereum network. We researched 3 Ethereum networks, namely: Ethereum mainnet, Ethereum testnet Ropsten, and Ethereum testnet Rinkeby. We analyze the computational resource utilization required to run an Ethereum node for a month as well as the costs involved. Research shows that the utilization of computing resources on the Main Net is generally higher than on the Test Net network. Computing resources used in the cloud cost thousands of dollars and this will increase as the number of nodes running to support the Ethereum network.
With the development of blockchain and digital currencies, central banks all over the world are accelerating the process of CBDC development. However, it is still controversial on adoption of blockchain in CBDC design. In the paper, we analyze both functional and non-functional requirements of CBDC design, and make a literature review on blockchain based CBDC schemes. Analysis findings show that permissioned blockchain is more suitable for CBDC than permissionless blockchain. Besides, there are some challenges in blockchain based CBDC, such as performance, scalability, and cross-chain interoperability. Our analysis is timely and can provide guidelines for blockchain based CBDC design.
Network Function Virtualization (NFV) is considered to be a hopeful technology for supporting blockchain with many features like flexible networks and intelligent equipment. NFV decreases the expenses incurred on the maintenance and operation of assets that are generated through expenses, in addition to capital expenditures based on the isolate the physical devices from the main tasks executed by that equipment. Blockchain currency transfers or technology is the most powerful security tool that ensures the security of data. The prominent challenges in NFV are the processes of transition, vendor compatibility, network management, rapid growth, and security. The software industry and skills of networking are experiencing fast expansion and deployment of the Network Functions Virtualization (NFV) approach, jointly in blockchain and cloud networks. In this paper, a novel method is offered to virtualize the work of the blockchain based on the NFV with auto work of the smart contract between virtual nodes based on cloud computing. By blending NFV with Blockchain, all of the above-mentioned challenges have been overcome by moving to software environments through creating virtual nodes, as well as smooth interaction among them and managing the transactions between nodes and clients, indicating ideal network management. Through the proposed work, a throughput of up to 20% is obtained by applying NFV compared to not applying NFV to the blockchain. In addition, the costs of the hardware are eliminated and eventually a secure environment is used which distances the system from virtual attacks.
Large cloud providers such as AWS and IBM now provide managed blockchain platforms, showcasing an active interest in blockchains. Unfortunately, blockchains provide poor performance and scalability. This is true even for the Execute-Order-Validate (EOV) style of blockchains which improves over the traditional Order-Execute architecture. We experimentally show that EOV platforms scale poorly using both vertical and horizontal scaling approaches. We find that the throughput is bottlenecked by the Validation and Commit phases, which poorly utilize the resources, limiting performance and scalability.
Blockchain is a very extraordinary innovation after the internet. Blockchain has become known as a public ledger for all transactions. It solves the problem of double spending by combining the technology with public key cryptography. However, globally, there will be more and more innovations created related to current innovations. One is a digital process compatible business, the former will help solve trust issues more efficiently over the network. We will propose that although blockchain has enabled Bitcoin, the most successful digital currency, its wide adoption in finance and other business sectors will represent many business discoveries and many research opportunities. This paper focuses on an overview of blockchain research development and also introduces specific issues.
Recent years have witnessed the advancement of the Internet of Things (IoT) and its emergence as a technology that could revolutionize many businesses. It helps considerably in creating data-driven business models with the insights it provides. IoT systems are deployed in data collection, monitor processes, provide insights and allow businesses to make data-driven productivity improvements. However, IoT systems are often experiencing data loss due to inevitable failures ranging from devices, networks, to the application layer, especially in scarce infrastructure resources environments. Data loss might be unrecoverable in many circumstances. As such, this research presents a blockchain based IoT model (framework) with the aim of circumventing data loss. We envisioned IoT blockchain technology in enhancing data veracity with data loss tolerance. That is, to have blockchain enhancing the IoT data veracity by leveraging on the features existed in its peer-to-peer network (P2P) and distributed ledger storage technology (DLT). Additionally, the edge computing of IoT blockchain technology is also conceptually workable; with intelligent small computing resources, it opens up a new era of bringing the intelligence of data collection, connectivity, computation and storage into the edge/device layer. A novel IoT blockchain strength monitoring system is also been studied to further enhance data veracity; this is achieved through a capacitance monitoring on the IoT blockchain system. The empirical results show that the proposed IoT blockchain with a strength monitoring model can alleviate data loss and thus enhance data veracity with data loss tolerance.
Blockchain technology introduces a new approach to storing information, implementing tasks and functions, and building trust between participating nodes. Although blockchain technology has received extensive attention in various application contexts in recent years, the issue of privacy and security remains the primary focus of discussions of the blockchain. The use of hash algorithms can provide secure blockchain integration, and many hash algorithms offer solutions to data integrity and security problems within the context of blockchain technology. However, they are also subject to problems related to time, lack of resources, and memory usage. In this research, an algorithm is proposed to generate a hash based on chaos theory (1D and 2D) logistic maps and the new Merkle-Damgård construction. Hash outputs are tested in terms of time, complexity, and collision. The proposed algorithm is evaluated according to Jaccard similarity and various coefficient measurements, and it was found that the similarity between the inputs and the outputs does not exceed 0.1932 percent. All outcomes indicated successful performance. The proposed algorithm was implemented on a blockchain-based transaction flow system, consumed fewer resources than other hash algorithms (such as SHA1, SHA2, and MD5), and requires mere milliseconds to implement.
Service fulfillment for clients increasingly involves cooperation between information technology (IT) systems. Designing such solutions requires an architectural approach that ensures symmetry between the communicating parties. For the design of such systems, the author introduces the 1+5 architectural views model. The model contains three new architectural views. For business process modeling, it ensures the integrated processes view. Integration aspects cover two additional views: integrated services, and contracts. Moreover, new stereotypes and tagged values have been added to the unified modeling language (UML). The author has introduced two profiles: UML profile for integration flows, and UML profile for distributed ledger deployment. Communication between systems requires flows that arrange mediation mechanisms. The paper describes an integration flow diagram that extends a UML activity diagram. In the case of blockchain, the author has proposed the smart contract design pattern. The paper describes three case studies that have employed the model to design various solutions. The 1+5 model has proven to be well suited for designing both centralized integration environments with enterprise service bus (ESB) and distributed blockchain solutions with peer-to-peer (P2P) connections.
Ethereum is an emerging distributed computing platform that supports a decentralized replicated virtual machine at a large scale. Transactions in Ethereum are specified in smart contracts, disseminated through broadcast, accepted into the chain of blocks, and then executed on each node. In this new Dissemination-Consensus-Execution (DiCE) paradigm, the time interval between when a transaction is known (during the dissemination phase) to when the transaction is executed (after the consensus phase) offers a window of opportunity to accelerate transaction processing through speculative execution. However, the traditional speculative execution, which hinges on the ability to predict the future accurately, is inadequate because of DiCE's many-future nature.
Viraaji Mothukuri, Sai S. Cheerla, Reza M. Parizi, Qi Zhang · 5 authors
Hadoop Distributed File System (HDFS) is one of the widely used distributed file systems in big data analysis for frameworks such as Hadoop. HDFS allows one to manage large volumes of data using low-cost commodity hardware. However, vulnerabilities in HDFS can be exploited for nefarious activities. This reinforces the importance of ensuring robust security to facilitate file sharing in Hadoop as well as having a trusted mechanism to check the authenticity of shared files. This is the focus of this paper, where we aim to improve the security of HDFS using a blockchain-enabled approach (hereafter referred to as BlockHDFS). Specifically, the proposed BlockHDFS uses the enterprise-level Hyperledger Fabric platform to capitalize on files' metadata for building trusted data security and traceability in HDFS.
Over the past decade, service provisioning in federated cloud environments (FCE) through multiple cloud service providers (CSP) is distributed among multi-cloud users (CU). In such ecosystems, multiple broker entities facilitate seamless performance and delivery of cloud services among CU and CSP in FCE. However, due to the exchange of information through public heterogeneous channels, the service transactions among cloud stakeholders are bounded by security issues such as privacy, the authenticity of stakeholders, chronology among transactions, and responsive availability of CSP. Thus, in such peer decentralized ecosystems, the blockchain (BC) framework is applicable to solve the aforementioned issues. BC also automates the Service level agreement (SLA) contracts between CU and CSP through smart contract (SC) execution as logical software codes. In the same direction, the proposed survey addresses the gaps in earlier multi-cloud surveys and discusses a BC-based secure broker provisioning framework for performance and security parameters, concerning associated attack vectors. The proposed survey presents a detailed analysis of different existing solutions and proposes a solution taxonomy for service provisioning in BC-envisioned cloud ecosystems. The survey also identifies the research challenges for industry professionals, academicians, and the research community, to build scalable services for CUs in FCE.
Quiz sites are typically made up of a front end, a back end, and a database of questions. Our objective is to further commonize this structure. Problem verification and solution keeping are aspects that have already been thoroughly studied and modified. However, the fairness of answer validation is often unclear to the end user. We propose a system that reduces the cost of creating a quiz site and a quiz scoring system for e-learning by putting part of the structure on a blockchain. Our system verifies answers using zero-knowledge proofs, stores the answers with Ethereum, an open-source platform for decentralized applications, and tracks them. Blockchain can be used to prevent the falsification of answer records. Ethereum is a new technique that has attracted considerable attention in recent years, and we use its program executions, i.e., smart contracts, to validate answers. After receiving an answer, the system stores it as an Ethereum transaction event.
Oct 10, 2021·Proceedings of the ... Annual Hawaii International Conference on System Sciences/Proceedings of the Annual Hawaii International Conference on System Sciences
Johannes Sedlmeir, Tim Wagner, Emil Djerekarov, Ryan Green · 6 authors
Enterprises have been attracted by the capability of blockchains to provide a single source of truth for workloads that span companies, geographies, and clouds while retaining the independence of each party's IT operations. However, so far production applications have remained rare, stymied by technical limitations of existing blockchain technologies and challenges with their integration into enterprises' IT systems. In this paper, we collect enterprises' requirements on distributed ledgers for data sharing and integration from a technical perspective, argue that they are not sufficiently addressed by available blockchain frameworks, and propose a novel distributed ledger design that is "serverless", i.e., built on cloud-native resources. We evaluate its qualitative and quantitative properties and give evidence that enterprises already heavily reliant on cloud service providers would consider such an approach acceptable, particularly if it offers ease of deployment, low transactional cost structure, and a combination of latency and scalability aligned with real-time IT application needs.
Kashif Mehboob Khan, Junaid Arshad, Waheed Iqbal, Sidrah Abdullah · 5 authors
Abstract Cloud computing is an important technology for businesses and individual users to obtain computing resources over the Internet on-demand and flexibly. Although cloud computing has been adopted across diverse applications, the owners of time-and-performance critical applications require cloud service providers’ guarantees about their services, such as availability and response times. Service Level Agreements (SLAs) are a mechanism to communicate and enforce such guarantees typically represented as service level objectives (SLOs), and financial penalties are imposed on SLO violations. Due to delays and inaccuracies caused by manual processing, an automatic method to periodically verify SLA terms in a transparent and trustworthy manner is fundamental to effective SLA monitoring, leading to the acceptance and credibility of such service to the customers of cloud services. This paper presents a blockchain-based distributed infrastructure that leverages fundamental blockchain properties to achieve immutable and trustworthy SLA monitoring within cloud services. The paper carries out an in-depth empirical investigation for the scalability of the proposed system in order to address the challenge of transparently enforcing real-time monitoring of cloud-hosted services leveraging blockchain technology. This will enable all the stakeholders to enforce accurate execution of SLA without any imprecisions and delays by maintaining an immutable ledger publicly across blockchain network. The experimentation takes into consideration several attributes of blockchain which are critical in achieving optimum performance. The paper also investigates key characteristics of these factors and their impact to the behaviour of the system for further scaling it up under various cases for increased service utilization.
Diego Fernandes Gonçalves Martins, Marco Aurélio Amaral Henriques
Este artigo apresenta um novo método de consenso para blockchains públicas baseado em Proof-of-Stake que não precisa de comitês de validação para aceitar novos blocos. Primeiramente, o texto mostra os princípios do mecanismo e como um nó é selecionado para criar um bloco na cadeia. Logo depois, é apresentado o processo de confirmação probabilística como forma de tornar definitiva a aceitação de um bloco sem comitês de validação, além de resultados práticos que avaliam o desempenho e a segurança do mecanismo. A segurança do método é demonstrada por um estudo teórico da probabilidade de reversão de blocos.
Xiaogang Xing, Yuling Chen, Tao Li, Yang Xin · 5 authors
Abstract Blockchain technology has the characteristics of decentralization and tamper resistance, which can store data safely and reduce the cost of trust effectively. However, the existing blockchain system has weak performance in data management, and only supports traversal queries with transaction hashes as keywords. The query method based on the account transaction trace chain (ATTC) improves the query efficiency of historical transactions of the account. However, the efficiency of querying accounts with longer transaction chains has not been effectively improved. Given the inefficiency and single method of the ATTC index in the query, we propose a subchain-based account transaction chain (SCATC) index structure. First, the account transaction chain is divided into subchains, and the last block of each subchain is connected by a hash pointer. The block-by-block query mode in ATTC is converted to the subchain-by-subchain query mode, which shortens the query path. Multiple transactions of the same account in the same block are merged and stored, which simplifies the construction cost of the index and saves storage resources. then, the construction algorithm and query algorithm is given for the SCATC index structure. Simulation analysis shows that the SCATC index structure significantly improves query efficiency.
The blockchain system allows various trans-actions and information storage to be executed in a decentralized manner, while smart contracts require multiple nodes to be executed in the local sandbox environment according to preset settings to ensure the consistency of each node, which makes smart contracts unable to proactively obtain data from the outside world. Decentralized oracle can realize the acquisition of off-chain data with a low speed under the premise of ensuring the decentralization of the blockchain. Some oracles use on-chain data storage and maintenance to speed up data acquisition, but this will face higher costs of data storage and maintenance, so current oracles cannot simultaneously ensure privacy and security while taking into account execution cost and processing speed. In this article, we propose Select-Storage, a new oracle design pattern to achieve low operating cost and high processing speed without compromising security. Through experimental analysis, and comparison with other design patterns in processing time and on-chain and off-chain call costs, we have proved the superiority of the Select-Storage design pattern.