Sebastian Mßller, Andreas Penzkofer, Nikita Polyanskii, Jonas Theis ¡ 6 authors
The Unspent Transaction Output (UTXO) model is commonly used in the field of Distributed Ledger Technology (DLT) to transfer value between participants. One of its advantages is that it allows parallel processing of transactions, as independent transactions can be added in any order. This property of order invariance and parallelisability has potential benefits in terms of scalability. However, since the UTXO Ledger is an append-only data structure, this advantage is compromised through the presence of conflicting transactions. We propose an extended UTXO Ledger model that optimistically updates the ledger and keeps track of the dependencies of the possible conflicts. In the presence of a conflict resolution mechanism, we propose a method to reduce the extended ledger back to a consistent UTXO Ledger.
Blockchain has received great attention in academia and industry due to its decentralization and immutability. From the perspective of transaction processing, blockchain is a distributed shared ledger and database with the characteristics of decentralization, traceability, and transparency. These features ensure the security of blockchainâs reliability. However, because a blockchain network requires complex consensus verification between users, it causes problems such as a high cost of data exchange and a low system throughput. Such problems are aggravated when executing a cross-chain transaction, as it is particularly important to ensure the atomicity and isolation of transactions across the blockchain. Considering this, in this paper, we propose the cross-chain transaction processing flow of EOVPC and efficient transaction processing based on version control. Different from the existing cross-chain transaction approaches based on locking, we propose optimistic approaches in which the updated data can be used immediately, with a rolling back procedure that guarantees atomicity. We conducted extensive experiments, which show that our approaches can improve the throughput and success rate significantly.
After the success of the Bitcoin blockchain, came several cryptocurrencies and blockchain solutions in the last decade. Nonetheless, Blockchain-based systems still suffer from low transaction rates and high transaction processing latencies, which hinder blockchains' scalability. An entire class of solutions, called Layer-1 scalability solutions, have attempted to incrementally improve such limitations by adding/modifying fundamental blockchain attributes. Recently, a completely different class of works, called Layer-2 protocols, have emerged to tackle the blockchain scalability issues using unconventional approaches. Layer-2 protocols improve transaction processing rates, periods, and fees by minimizing the use of underlying slow and costly blockchains. In fact, the main chain acts just as an instrument for trust establishment and dispute resolution among Layer-2 participants, where only a few transactions are dispatched to the main chain. Thus, Layer-2 blockchain protocols have the potential to transform the domain. However, rapid and discrete developments have resulted in diverse branches of Layer-2 protocols. In this work, we systematically create a broad taxonomy of such protocols and implementations. We discuss each Layer-2 protocol class in detail and also elucidate their respective approaches, salient features, requirements, etc. Moreover, we outline the issues related to these protocols along with a comparative discussion. Our thorough study will help further systematize the knowledge dispersed in the domain and help the readers to better understand the field of Layer-2 protocols.
Kyle P. Michelson, Anjali Sridharan, Umut Can Ăabuk, Ethan Reesor ¡ 9 authors
The Accumulate Protocol ("Accumulate") is an identity-based, Delegated Proof of Stake (DPoS) blockchain designed to power the digital economy through interoperability with Layer-1 blockchains, integration with enterprise tech stacks, and interfacing with the World Wide Web. Accumulate bypasses the trilemma of security, scalability, and decentralization by implementing a chain-of-chains architecture in which digital identities with the ability to manage keys, tokens, data, and other identities are treated as their own independent blockchains. This architecture allows these identities, known as Accumulate Digital Identifiers (ADIs), to be processed and validated in parallel over the Accumulate network. Each ADI also possesses a hierarchical set of keys with different priority levels that allow users to manage their security over time and create complex signature authorization schemes that expand the utility of multi-signature transactions. A two token system provides predictable costs for enterprise users, while anchoring all transactions to Layer-1 blockchains provides enterprise-grade security to everyone.
Non-fungible tokens have been a unique transformation in the implementation of the concept of distributed ledger technology in digital assets. NFTs are said to be non-interchangeable, which distinguishes its value from fungible tokens like Bitcoin (Btc). Scammers are utilizing the open source nature of the blockchain to victimize users and steal their NFTs, leaving NFT collectors with infringed artwork. In a bid to eliminate security vulnerability and attack in NFT platform, we implemented a smart contract verification model. Our verification model is a 2-pronged approach that utilized F*, functional programming language. We presented two tools that translated solidity source code and EVM bytecode to solidity* and EVM* respectively. The EVM decompiler analyzes contracts in which the solidity source codes are unavailable as well as low level properties of contracts. The EVM* and Solidity* tools helped to check the equivalence between a solidity program and the bytecode output from the solidity compiler in order to avoid bugs and preserve verified properties at the source level. In this paper, Etherscan token tracker was used to verify and authenticate NFT token before buying or minting such NFT. Keywords: Non-Fungible Tokens (NFTs), The NFT- marketplace (NFTM), Ethereum
The aim of the paper is to present the new factors of ERP (Enterprise Resource Planning system) implementation related to the usage of cloud-based and blockchain information technology and to discover potential possibilities of using cloud computing, big data, and blockchain technologies in the methodology of ERP implementation. The article covers the characteristics of the current implementation methodologies and also discusses how these technologies can be adopted in the implementation process. During the study, a literature review was carried out and survey-based interviews with project managers were performed. Previous studies examined in the literature review have some limitations. Most of them are focused on ERP performance in the cloud or measure success factors of ERP implementation. A research gap exists regarding the impact of technologies in the implementation process and the results of this process. The research shed some light on cloud computing and blockchain in ERP implementation. The conclusions are as follows: (1) Some methods of sustainable methods of ERP implementation with the use of cloud technologies, blockchain, and big data have been examined in research studies, but there is still a lack of publications with in-depth analyses of the impact of blockchain on ERP implementation success. (2) The practitioners recommended the new technologies based on cloud computing and big data in the process of ERP implementation, and more knowledge about blockchain would have a positive impact on the success of sustainable ERP implementation as well as on the willingness to adopt the new technologies.
Akram Alofi, Mahmoud A. Bokhari, Rami Bahsoon, Robert Hendley
Blockchain technology has gained recognition in industrial, financial, and various technological domains for its potential in decentralizing trust in peer-to-peer systems. A core component of blockchain technology is a consensus algorithm, most commonly Proof of Work (PoW). PoW is used in blockchain-based systems to establish trust among peers; however, it does require the expenditure of an enormous amount of energy that affects the environmental sustainability of blockchain-based systems. Energy minimization, whilst ensuring trust within blockchain-based systems that use PoW, is a challenging problem. The solution has to consider how energy consumption can be minimized without compromising trust, whilst still ensuring, for instance, scalability, security, and decentralization. In this paper, we represent the problem as a subset selection problem of miners in a blockchain-based system. We formulate the problem of blockchain energy consumption as a Search-Based Software Engineering problem with four objectives: energy consumption, carbon emission, decentralization, and trust. We propose a model composed of multiple fitness functions. The model can be used to explore the complex search space by selecting a subset of miners that minimizes the energy consumption without drastically impacting the primary goals of the blockchain technology (i.e., security/trustworthiness and decentralization). We integrate our proposed fitness functions into five evolutionary algorithms to solve the problem of blockchain miners selection. Our results show that the environmental sustainability of blockchain-based systems (e.g. reduced energy use) can be enhanced with little degradation in other competing objectives. We also report on the performance of the algorithms used.
Nguyen Khoi Tran, Muhammad Ali Babar, Andrew J. Walters
Blockchain network deployment and evaluation have become prevalent due to the demand for private blockchains by enterprises, governments, and edge computing systems. Whilst a blockchain network's deployment and evaluation are driven by its architecture, practitioners still need to learn and carry out many repetitive and error-prone activities to transform architecture into an operational blockchain network and evaluate it. Greater efficiency could be gained if practitioners focus solely on the architecture design, a valuable and hard-to-automate activity, and leave the implementation steps to an automation framework. This paper proposes an automation framework called NVAL (Network Deployment and Evaluation Framework), which can deploy and evaluate blockchain networks based on their architecture specifications. The key idea of NVAL is reusing and combining the existing automation scripts and utilities of various blockchain types to deploy and evaluate incoming blockchain network architectures. We propose a novel meta-model to capture blockchain network architectures as computer-readable artefacts and employ a state-space search approach to plan and conduct their deployment and evaluation. An evaluative case study shows that NVAL successfully combines seven deployment and evaluation procedures to deploy 65 networks with 12 different architectures and generate 295 evaluation datasets whilst incurring a negligible processing time overhead.
In blockchains , transaction fees are fixed by the users. The probability for a transaction to be processed quickly increases with the fee level. In this paper, we study the transaction fee optimization problem in the Ethereum blockchain. This problem consists of determining the minimum price a user should pay so that its transaction is processed with a given probability in a given amount of time. To reach this goal, we define a new solution method based on a Monte Carlo approach to predict the probability that a transaction will be mined within a given time limit. Numerical results on real data highlight the quality of the results.
Abstract Blockchain is a distributed ledger based on peerâtoâpeer networks, originally used for cryptoâcurrency systems. Blockchains are being used as an enabling technology for decentralised applications in the areas of InternetâofâThings, finance, supplyâchain and others. Consistency, data privacy, performance, and energy efficiency are of paramount importance in such applications. The full nodes of public, permissionless blockchains undertake the task of verifying the transactions generated by the network. Full nodes perform operations such as confirming balances, transactions, and history, i.e. mostly database search queries. Consequently, their throughput is crucial for the performance of blockchain systems. In this work, the benefits of accelerating the blockchain search and insert queries by leveraging GPU platforms are studied. An extensive comparison between the most dominant utilized database is provided, i.e. LevelDB, and MegaKV, a highâperformance GPUâaccelerated database. Realistic operations that take place in blockchain systems are emulated and evaluated over representative scenarios, showing three orders of magnitude gains in throughput and energy efficiency without compromising the security aspect. The extensive comparison between LevelDB and MegaKV indicates that GPU acceleration is an effective solution for runtime and energy efficiency enhancement of blockchain systems, and the integration of the two technologies is a promising field of research.
In the blockchain context, the information system (IS) is considered a part of its infrastructure. However, blockchain itself can be used for IS development using software components and services. As the trust for binary components or services is still a problem, we propose to use the blockchain of components to solve this problem. In this paper, the part of such solution, namely consensus algorithms, is discussed. We focus on Proof-of-Stake algorithms and present their feasibility to be used in the blockchain of software components. It was found that the use of probabilistic algorithms (RRR, CloudPoS, WV, DDPoS, Panda) allow the partial solution of the problem in the blockchain of reliable software components.
Sharding is a solution to the blockchain scalability problem. A sharded blockchain divides consensus nodes (validators) into groups called shards and processes transactions separately to improve throughput and latency. In this paper, we analyze the rational behavior of users in account/balance model-based sharded blockchains and identify a phenomenon in which accounts (users' wallets and smart contracts) eventually get concentrated in a few shards, making shard loads unfair. This phenomenon leads to bad user experiences, such as delays in transaction inclusions and increased transaction fees. To solve this problem, we propose two load balancing methods in account/balance model-based sharded blockchains. Both methods perform load balancing by periodically reassigning accounts: in the first method, the blockchain protocol itself performs load balancing and in the second method, wallets perform load balancing. We discuss the pros and cons of the two protocols, and apply the protocols to the execution sharding in Ethereum 2.0, an existing sharding design. Further, we analyze by simulation how the protocols behave to confirm that we can observe smaller transaction delays and fees. As a result, we released the simulation program as âShargri-La,â a simulator designed for general-purpose user behavior analysis on the execution sharding in Ethereum 2.0.
Marco Schletz, Angel Hsu, Brendan R. Mapes, Martin Wainstein
The Paris Agreementâs decentralized and bottom-up approach to climate action poses an enormous accounting challenge by substantially increasing the number of heterogeneous national, sub-national, and non-state actors. Current legacy climate accounting systems and mechanisms are insufficient to avoid information asymmetry and double-counting due to actor heterogeneity and fragmentation. This paper presents a nested climate accounting architecture that integrates several innovative digital technologies, such as Distributed Ledger Technology, Internet of Things, Machine Learning, and concepts such as nested accounting and decentralized identifiers to improve interoperability across accounting systems. Such an architecture can enhance capacity building and technology transfer to the Global South by creating innovation groups, increasing scalability of accounting solutions that can lead to leapfrogging into innovative systems designs, and improving inclusiveness.
It is interesting but difficult and challenging to study Ethereum with multiple mining pools. One of the main difficulties comes from not only how to represent such a general tree with multiple block branches (or sub-chains) related to the multiple mining pools, but also how to analyze a multi-dimensional stochastic system due to the mining competition among the multiple mining pools. In this paper, we first set up a mathematical representation for the tree with multiple block branches. Then we provide a block classification of Ethereum: Regular blocks (in the main chain), orphan blocks, uncle blocks, stale blocks, and nephew blocks, and give some key ratios and probabilities of generating the different types of blocks by applying the law of large numbers. Based on this, we further discuss the growth rate of blockchain and the reward allocation among the multiple mining pools through applying the renewal reward theorem. Finally, we use some simulation experiments to verify our theoretical results, and show that the approximate computation approaches developed, such as the key ratios and probabilities, the long-term growth rate of blockchain, and the long-term reward allocation (rate) among the multiple mining pools, can have a faster convergence. Therefore, we provide a powerful tool for observing and understanding the influence of the selfish mining attacks on the performance of Ethereum with multiple mining pools. We believe that the methodology and results developed in this paper will shed light on the study of Ethereum with multiple mining pools, such that a series of promising research can be inspired potentially.
Blockchain technology has gained prominence over the last decade. Numerous achievements have been made regarding how this technology can be utilized in different aspects of the industry, market, and governmental departments. Due to the safety-critical and security-critical nature of their uses, it is pivotal to model the dependability of blockchain-based systems. In this study, we focus on Bitcoin, a blockchain-based peer-to-peer cryptocurrency system. A continuous-time Markov chain-based analytical method is put forward to model and quantify the dependability of the Bitcoin system under selfish mining attacks. Numerical results are provided to examine the influences of several key parameters related to selfish minersâ computing power, attack triggering, and honest minersâ recovery capability. The conclusion made based on this research may contribute to the design of resilience algorithms to enhance the self-defense and robustness of cryptocurrency systems.
Blockchain is the distributed decentralized application for developing many of the use cases. In blockchain, the applications are transparent to all the nodes in the decentralized network and the application may be private or public depends upon the use cases. The nodes in the distributed network shares all the data to the other nodes without any modification in the blockchain technology. The transaction by the node is secured through the digital signatures. In this paper, we implemented the application by confirming the transaction without paying the gas fee by deploying the smart contract. The solidity is a JavaScript programming language for writing our smart contract. We explained the gas optimization technique used by the users and the gas station network in a decentralized application and also explained about the parameters in the Ethereum transactions. We used the open zeppelin library, which allows us to run our đˇđđđ to implement the gasless transaction.
Claudio Di Ciccio, Giovanni Meroni, Pierluigi Plebani
Abstract Being the blockchain and distributed ledger technologies particularly suitable to create trusted environments where participants do not trust each other, business process management represents a proper setting in which these technologies can be adopted. In this direction, current research work primarily focuses on blockchain-oriented business process design, or on execution engines able to enact processes through smart contracts. Conversely, less attention has been paid to study if and how blockchains can be beneficial to business process monitoring. This work aims to fill this gap by (1) providing a reference architecture for enabling the adoption of blockchain technologies in business process monitoring solutions, (2) defining a set of relevant research challenges derived from this adoption, and (3) discussing the current approaches to address the aforementioned challenges.
Nianqi Jiang, Fenhua Bai, Lin Huang, Zhengyuan An ¡ 5 authors
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 networkâs 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.
Pol Alemany, Ricard Vilalta, Raßl Muùoz, Ramon Casellas ¡ 5 authors
Data center (DC) interconnection allows us to have optical transmissions between DCs directly connected to optical networks, avoiding the use of a packet-based infrastructure. Thanks to the use of next-generation pluggable coherent optics, it is possible to create connectivity services (CSs) across multiple optical transport domains. In this multi-domain CS scenario, cloud operators and transport operators have to work together in the most dynamic way possible. To do so, they need a common place (i.e., a market) where the transport operators may expose their available optical resources and the cloud operators request (e.g., rent) them to be used in order to create end-to-end (E2E) CSs between DCs. Having multiple transport operators exposing their resource information in a common place requires a set of common rules (i.e., how much of the topology to show) to create E2E CSs requested between cloud operators. This paper makes use of the blockchain technology to present a blockchain-based extension for the software-defined network (SDN) architecture to allow each optical transport operator domain to become a peer in a blockchain network. In there, each peer follows the same rules and shares the same exact level of topology information by using a specific abstraction model to map the optical domain resources. This paper uses a set of three different abstraction models to validate their behavior on a blockchain system when managing multiple domain resources and the deployment of CSs across these domains. To do so, an experimental comparison on how the different abstraction models affect the performance of the blockchain system is presented.
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 faultâtolerant consensus mechanism (DEâBFT) 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 DEâBFT algorithm performs better in terms of consensus delay, communication overhead, throughput, and consensus node reliability.
M. Sumathi, N. Vijayaraj, S. P. Raja, Venkatachalapathy Maharajan
HIGHLIGHTS The permissioned blockchain is used for resource allocation and monitoring. To reduce storage size, partial data is stored in the onchain blocks instead of entire data. The EUâs based Fixed and variable size resource allocation techniques are proposed.
Vladislav Amelin, Ernest Gatiyatullin, Nikita S. Romanov, Ratmir Samarkhanov ¡ 6 authors
This paper introduces a function for blockchain performance evaluation as a black-box. The function runs the Solana blockchain test network with the only differences between the main network in a configuration file and the physical network to operate in. The black-box takes setup parameters as input, launches blockchain in a cloud, emulates artificial usersâ activity, and gives two outputsâtransactions per second (tps) and drop rate. By default, the setup has six most important integer parameters and a network with three computers in the cloud, while one can vary eighty-nine parameters, the number of computers in the network and use local computers via black-box configuration files. The applied problem is to maximize the tps under a zero drop rate constraint. The black-box, like real blockchains, uses network communication, so reproducibility is an essential part of the design. We also provide an optimization baseline, showing the non-trivial resultsâ reachability.
This paper shows the performance and scalability evaluation of different blockchain platform implementations. Hyperledger Iroha implementing YAC consensus, Sawtooth implementing PoET algorithm, and Hyperledger Fabric framework implementation. Performance evaluation and scalability assessment were done by varying different sets of parameters such as block size, transaction sending rate, network traffic distribution, and network size. Performance evaluation was done based on average transaction latency, network throughput, and transaction failure rate. Scalability was assessed based on changes in transaction latency and throughput with increasing network size. Test results let to study the impact of a particular parameter on the private blockchain network performance and show how they can be adjusted to improve performance.