Andrea Pinna, Maria Ilaria Lunesu, Stefano Orrù, Roberto Tonelli
Technical debt refers to decisions made during the design and development of software that postpone the resolution of technical problems or the enhancement of the software’s features to a later date. If not properly managed, technical debt can put long-term software quality and maintainability at risk. Self-admitted technical debt is defined as the addition of specific comments to source code as a result of conscious and deliberate decisions to accumulate technical debt. In this paper, we will look at the presence of self-admitted technical debt in open-source blockchain projects, which are characterized by the use of a relatively novel technology and the need to generate trust. The self-admitted technical debt was analyzed using NLP techniques for the classification of comments extracted from the source code of ten projects chosen based on capitalization and popularity. The analysis of self-admitted technical debt in blockchain projects was compared with the results of previous non-blockchain open-source project analyses. The findings show that self-admitted design technical debt outnumbers requirement technical debt in blockchain projects. The analysis discovered that some projects had a low percentage of self-admitted technical debt in the comments but a high percentage of source code files with debt. In addition, self-admitted technical debt is on average more prevalent in blockchain projects and more equally distributed than in reference Java projects.If not managed, the relatively high presence of detected technical debt in blockchain projects could represent a threat to the needed trust between the blockchain system and the users. Blockchain projects development teams could benefit from self-admitted technical debt detection for targeted technical debt management.
The integration of cloud computing and big data has revolutionized data storage, processing, and analytics. However, this convergence also presents significant challenges regarding data privacy, security breaches, and compliance with regulatory standards. This paper examines privacy and security concerns in cloud-integrated big data systems through a case study approach, identifying vulnerabilities, mitigation strategies, and best practices. By analyzing real-world implementations across healthcare, finance, and government sectors, this study provides actionable insights for designing more secure cloud-based big data infrastructures. Findings suggest that a combination of cryptographic techniques, decentralized architectures, and adaptive security models significantly enhances system resilience.
In this paper, we propose HybridCoin, a next-generation cryptocurrency that combines the advantages of both Bitcoin and Ethereum to create a highly versatile and efficient digital asset. The goal of HybridCoin is to unite Bitcoin’s proven store of value and robust security features with Ethereum’s powerful programmability and smart contract capabilities, thereby enabling a wide range of use cases and applications. We present the design and architecture of HybridCoin, with a focus on the consensus mechanism, scalability solutions, and smart contract functionality. We also discuss the security and privacy features of the proposed cryptocurrency, along with its potential use cases in digital payments, decentralized finance (DeFi), and asset management. Furthermore, we address the environmental sustainability and energy efficiency aspects of HybridCoin, offering strategies for sustainable blockchain operations. Finally, we explore the regulatory landscape and potential challenges faced by HybridCoin, including the impact of emerging trends, technological innovations, and the rise of Central Bank Digital Currencies (CBDCs). By integrating the strengths of both Bitcoin and Ethereum, HybridCoin has the potential to revolutionize the cryptocurrency ecosystem and reshape the future of digital finance.
Non-fungible tokens (NFTs) are becoming increasingly popular in Play-to-Earn (P2E) Web3 applications as a means of incentivizing user engagement. In Web3, users with NFTs ownership are entitled to monetize them. However, due to lack of objective NFT valuation, which makes NFT value determination challenging, P2E applications ecosystems have experienced inflation. In this paper, we propose a method that enables NFT inflation value management in P2E applications. Our method leverages the contribution-rewards model proposed by Curve Finance and the automated market maker (AMM) of decentralized exchanges. In decentralized systems, P2E Web3 applications inclusive, not all participants contribute in good faith. Therefore, rewards are provided to incentivize contribution. Our mechanism proves that burning NFTs, indicating the permanent removal of NFTs, contributes to managing inflation by reducing the number of NFTs in circulation. As a reward for this contribution, our method mints a compensation (CP) token as an ERC-20 token, which can be exchanged for NFTs once enough tokens have been accumulated. To further increase the value of the CP token, we suggest using governance tokens and CP tokens to create liquidity pools for AMM. The value of the governance token is determined by the market, and the CP token derives its value from the governance token in AMM. The CP token can determine its worth based on the market value of the governance token. Additionally, since CP tokens are used for exchanging NFTs, the value of the NFT is ultimately determined by the value of the CP token. To further illustrate our concept, we show how to adjust burning rewards based on factors such as the probability of upgrading NFTs' rarity or the current swap ratio of governance and CP tokens in AMM.
Rafael Belchior, Jan Süßenguth, Qi Feng, Thomas Hardjono · 6 authors
Blockchain interoperability conflates the need for distributed systems to communicate with third- party systems without the existence of a canonical chain or orchestration layer. As there is not “a chain to rule them all” (due to reasons such as performance, privacy, and market forces), these distributed systems rely on exchanging data and value across network boundaries. Interconnected systems achieve a higher value than the sum of their parts, similar to how the Internet emerged as a set of isolated Local Area Networks (LANs) - and, by force of surprising synergies, such networks fundamentally transformed society, forever. Concurrently, in the last decade, we have witnessed the astonishing development of blockchain technologies, which seem more connected than ever: via bridges [13, 15, 16, 31], oracles [45], and other interoperability mechanisms [4, 9, 17, 48, 89]. These recent developments have, slowly but steadily, contributed to the improvement of the scalability of blockchain networks, as well as providing new functionality and use cases [66], but there is still a long way to go until mass adoption. In this paper, we will dive into the rabbit hole of blockchain interoperability and explain why it is needed, what has been done in the last decade, and where it is going.
Blockchain adopts a chain data structure, and the characteristics of blocks that can only be added and cannot be deleted make the total number of blocks accumulate over time, forcing resource-constrained nodes to become degraded nodes in order to alleviate increasingly severe storage pressure. Degraded nodes only store partial blocks, although improving the scalability of blockchain storage and reducing data redundancy will lead to a decrease in data availability. To address the problem of storage scalability, quantitative research is needed on data availability. Based on a summary of the existing definitions of data availability, we propose a definition of data availability for blockchain. By analyzing the data synchronization process and the transaction lifecycle, key factors affecting data availability were extracted, and a data availability measurement model was constructed based on node types. On this basis, a relationship model linking data availability and storage scalability was constructed to find the range of data redundancy that meets the target data availability. The experimental results indicate that the data availability measurement model for blockchain can measure the data availability levels of different scalable storage schemes. The model of the relationship between data availability and storage scalability can guide the setting of data redundancy in scalable storage schemes.
Blockchain has received attention for its potential use in business. Bitcoin is powered by blockchain, and interest in it has surged in the past few years. It has many uses that need to be modeled. Modeling is used in many walks of life to share ideas, reduce complexity, achieve close alignment of one person viewpoint with another and provide abstractions of a system at some level of precision and detail. Software modeling is used in Model Driven Engineering (MDE), and Domain Specific Languages (DSLs) ease model development and provide intuitive syntax for domain experts. The present study has designed and evaluated a meta-model for the bitcoin application domain to facilitate application development and help in truly understanding bitcoin. The proposed meta-model, including stereotypes, tagged values, enumerations and a set of constraints defined by Object Constraint Language (OCL), was defined as a Unified Modeling Language (UML) profile and was implemented in the Sparx Enterprise Architect (Sparx EA) modeling tool. A case study developed by our meta-model is also presented.
Abstract The creation of blockchain-based software applications requires today considerable technical knowledge, particularly in software design and programming. This is regarded as a major barrier in adopting this technology in business and making it accessible to a wider audience. As a solution, low-code and no-code approaches have been proposed that require only little or no programming knowledge for creating full-fledged software applications. In this paper we extend a review of academic approaches from the discipline of model-driven engineering as well as industrial low-code and no-code development platforms for blockchains. This includes a content-based, computational analysis of relevant academic papers and the derivation of major topics. In addition, the topics were manually evaluated and refined. Based on these analyses we discuss the spectrum of approaches in this field and derive opportunities for further research.
Despite the recent increase in the popularity of blockchain, the technology suffers from the trilemma trade-off between security decentralisation and scalability prohibiting adoption, and limiting the efficiency and effectiveness of the induced system. Addressing the trilemma trade-off calls for dynamic management and configuration of the blockchain system. In particular, choosing an effective and efficient consensus protocol for balancing the trilemma trade-off when inducing the blockchain-based system is acknowledged to be a challenging problem given the dynamic and complex nature of the blockchain environment. DDDAS approaches are particularly suitable for this challenge, and in previous work, the authors presented a novel DDDAS-based blockchain architecture and demonstrated that it offers a promising approach for dynamically adjusting the parameters of a system and optimising for the trade-off. This paper presents a novel simulation tool that can support and satisfy the DDDAS requirements for a dynamically re-configurable blockchain system. The tool supports the simulation and the dynamic switching of consensus protocols, analysing their trilemma trade-off. The simulator design is modular and allows the implementation and analysis of a wide range of consensus protocols and their implementation scenarios, along with the ability for parallelization. The paper also presents a quantitative evaluation of the tool.
Abstract: The advancement of blockchain innovation has prompted the making of decentralized applications (DApps), which permit client collaboration without the utilization of mediators. One of the most generally used blockchain stages for making DApps is Ethereum, which conducts business utilizing its own cash, Ether. Using Metamask, React.js, Node.js, and Solidity, we demonstrate the design and implementation of a decentralised system for Ethereum transfer in this paper. Our technology allows users to safely move Ether between accounts without the usage of intermediaries. We use React.js and Node.js to make the web application, a program module called Metamask to communicate with Ethereum, and Solidity to make the brilliant agreements that make exchanges conceivable.
As the significance of blockchain innovation grows and the focus on scalability intensifies, rollup technology has emerged as a promising approach to tackle these scalability concerns. Nonetheless, rollups encounter restrictions when interacting with other rollups, leading to diminished throughput, increased latency, higher fees, and a complex user experience in transactions between rollups. In this paper, we put forth a novel system that employs batch settlement techniques to augment the efficiency of transfers between rollups. Our proposed system comprises a settlement rollup responsible for batch settling transfers among rollups and a smart contract structure that carries out the settlements. Notably, we utilize a zero-knowledge proof algorithm to guarantee the computational integrity of the settlement rollup while ensuring security through Ethereum smart contracts for proof verification and settlement execution. By implementing this approach, the proposed system can effectively and securely execute asset transfers between rollups, ultimately improving their scalability and usability. Consequently, our research provides a fresh perspective on resolving the challenges of throughput, latency, and fees associated with transfer systems.
George Melas, Alexandros Chatzigeorgiou, Apostolos Ampatzoglou
Smart Contracts (SC) are computer programs that run on blockchains and can be executed automatically in a deterministic way, when pre-determined conditions are met. Currently, Ethereum is the biggest blockchain network with more than 200,000 SCs deployed every month[1](#fn-0002). The main mechanism for financially managing and securing such networks is “ Gas Consumption ”. In particular, a gas cost is assigned to each operation that alters the blockchain state, based on the SC size and complexity. Thus, the cost that a SC incurs to its owner and users is related to the internal structure of the SC. By considering that the average cost for deploying a Smart Contract can reach up to thousands of euros, it becomes obvious that internal quality of SCs is of great importance. To this end, in this article we present a comprehensive analysis of the correlation of a set of code metrics (e.g., size, complexity) with the actual gas required to deploy Smart Contracts. The empirical evidence that we provide rely on the analysis of over 90,000 SCs. In addition to the produced empirical knowledge, in most of the cases validating the theoretical expectation, we have implemented a web-based application (Smart Contracts Quality Analysis Platform—SCQAP) that visualizes the findings, enabling the on-demand creation of correlation diagrams, and offers access to a public repository of our data (metrics and deployment gas consumption) via a REST API. To the best of our knowledge this is the biggest empirical study on SCs, which: (a) sets up the scene for further large-scale studies on Smart Contracts (through tooling and public dataset); and (b) provides guidance to software practitioners on parameters that can inflate deployment costs.
Blockchain proposes many innovative technologies to establish credible mechanisms in an open environment and therefore, it becomes a promising solution to the problem of credibility in educational development. To better understand the role of the blockchain, we aim to provide an extensive survey focusing on its key technology, application potential, and performance evaluation. First, from the perspective of blockchain characteristics, we summarize its application architecture in educational credibility. Next, we extensively discuss application potential of the blockchain, such as data storage, data sharing, achievement certification, and activity evaluation. Moreover, we investigate the performance evaluation, including basic performance metrics and specialized metrics for credibility. Finally, we analyze the challenges and research trends of blockchain in educational credibility and provide useful insights for future research.
Ronan D. Mendonça, Ericksulino Moura, Glauber Dias Gonçalves, Alex Borges Vieira · 5 authors
Blockchain é uma tecnologia que amplia a segurança nas relações entre organizações via o registro auditável e descentralizado de transações. Notadamente, há uma crescente atenção por aplicações que utilizam essa tecnologia. Entretanto, a eficiência e custo de tais aplicações pode ser influenciada pela rede blockchain utilizada. De fato, a escolha da rede impacta nas qualidades não funcionais das aplicações, em especial desempenho (e.g., em relação a taxa de transações efetivadas) e custo. Este artigo investiga o impacto no desempenho e custo da infraestrutura de rede blockchain para lidar com uma determinada carga de trabalho. Primeiramente, este artigo propõe um modelo de arquitetura de rede comum entre a rede pública Ethereum e permissionada Hyperledger Fabric com base em recursos por nó par da rede blockchain. A seguir, avalia-se o custo por transação para aplicações nessa arquitetura considerando latências e custos mínimos para os pares da rede, em função da carga de trabalho. Os experimentos realizados nas plataformas mais populares para redes blockchain, Ethereum e Hyperledger Fabric, mostram os limites de escalabilidade dessas plataformas e os seus compromissos entre custo e desempenho no projeto de aplicações baseadas em blockchain.
The problem of resource-saving scheduling in a fog environment is considered in this paper. The objective function of the problem in question presupposes the fog nodes’ reliability function maximizing. Therefore, to create a schedule, the following is required: the history of the fog devices’ state changes and the search space, which consists of preselected nodes of the cloud-fog broker neighbourhood. The obvious approach to providing the scheduler with this information is to poll the fog nodes, yet this can consume the unacceptable time because of the QoS requirements. In this paper, the system architecture and general methods for efficient resource-saving scheduling is presented. The system is based on distributed ledger element usage, which provides the nodes with the proper awareness about the surroundings. The usage of the distributed ledger allows not only for the creation of the resource-saving schedule but also the reduction of the scheduling problem-solving time, which frees addition time that can be used for the solving of user tasks. The latter also affects the overall resource-saving via reliability. The novelty of this paper consists in the development of the hybrid ledger-based system, which integrates and arranges the elements of various ledger types to solve the newly formulated problem.
Blockchain has received a lot of attention due to its immutability. However, the immutability characteristic prohibits editing the blocks which need to be modified. Although the existing redactable blockchain enables to manipulate blocks in a controlled way, it may suffer from the security threats if the number of honest committee members (CMs) is insufficient. Thus, to attract honest CMs for validating and voting the editing blocks in permissionless blockchain, this paper presents a contract-based incentive mechanism between contract issuer and every CM. Firstly, it models the interaction between the contract issuer and each CM in the verifying and voting process. Secondly, it builds an incentive mechanism according to the contract issuer’s cost and the committee size. Finally, it selects a sufficiently large number of CMs with an optimization method. The analysis shows that the present mechanism is secure against Sybil attack, and the simulations demonstrate that the proposed mechanism is effective.
Blockchain oracles are an intermediary designed to connect external non-deterministic information and real-world data to the blockchain digital infrastructure. The variety of proposed solutions and purposes are of great variety and suggest that it is necessary to take into account different features of the process and specifically define the required functionalities. The purpose of this paper is to present the integration of oracles into an EOSIO blockchain-based platform for smart crop production data exchange by smart contracts. The functions of two oracles are presented. Their integration is described at the design level and at the implementation of the smart contracts. The design level is illustrated by workflow diagrams of internal processes between oracle applications and the blockchain smart contract and by external processes in the oracles’ smart contracts. The implementation level is illustrated by oracle application configuration files and elements of C++ smart contracts, such as constant and variable declarations, multi-index tables, internal contract functions, and actions called by other contracts and external programs. As results of the oracles’ operation, a report on the detected emergency failures and an estimate of the cost of ram resource are presented.
A Practical Byzantine Fault Tolerance (PBFT) is a consensus algorithm deployed in a consortium blockchain that connects a group of related participants. This type of blockchain suits the implementation of the Building Information Modeling (BIM) information exchange with few participants. However, when much more participants are involved in the BIM information exchange, the PBFT algorithm, which inherently requires intensive communications among participating nodes, has limitations in terms of scalability and performance. The proposed solution for a multi-layer BFT hypothesizes that multi-layer BFT reduces communication complexity. However, having more layers will introduce more latency. Therefore, in this paper, Double-Layer Byzantine Fault Tolerance (DLBFT) is proposed to improve the blockchain scalability and performance of BIM information exchange. This study shows a double-layer network structure of nodes that can be built with each node on the first layer, which connects and forms a group with several nodes on the second layer. This network runs the Byzantine Fault Tolerance algorithm to reach a consensus. Instead of having one node send messages to all the nodes in the peer-to-peer network, one node only sends messages to a limited number of nodes on Layer 1 and up to three nodes in each corresponding group in Layer 2 in a hierarchical network. The DLBFT algorithm has been shown to reduce the required number of messages exchanged among nodes by 84% and the time to reach a consensus by 70%, thus improving blockchain scalability. Further research is required if more than one party is involved in multi-BIM projects.
Andrei Constantinescu, Diana Ghinea, Lioba Heimbach, Zilin Wang · 5 authors
Traditional blockchain design gives miners or validators full control over transaction ordering, i.e., they can freely choose which transactions to include or exclude, as well as in which order. While not an issue initially, the emergence of decentralized finance has introduced new transaction order dependencies allowing parties in control of the ordering to make a profit by front-running others' transactions. In this work, we present the Decentralized Clock Network, a new approach for achieving fair transaction ordering. Users submit their transactions to the network's clocks, which run an agreement protocol that provides each transaction with a timestamp of receipt which is then used to define the transactions' order. By separating agreement from ordering, our protocol is efficient and has a simpler design compared to other available solutions. Moreover, our protocol brings to the blockchain world the paradigm of asynchronous fallback, where the algorithm operates with stronger fairness guarantees during periods of synchronous use, switching to an asynchronous mode only during times of increased network delay.
Blockchain technology constitutes a paradigm shift in the way we conceive distributed architectures. A Blockchain system lets us build platforms where data are immutable and tamper-proof, with some constraints on the throughput and the amount of memory required to store the ledger. This paper aims to solve the issue of memory and performance requirements developing a multiple Blockchain architecture that mixes the benefits deriving from a public and a private Blockchain. This kind of approach enables small sensors - with memory and performance constraints - to join the network without worrying about the amount of data to store. The development is proposed following a context-aware approach, to make the architecture scalable and easy to use in different scenarios.
Vincent Gramoli, Rachid Guerraoui, Andrei Lebedev, Chris Natoli · 5 authors
With the recent advent of blockchains, we have witnessed a plethora of blockchain proposals. These proposals range from using work to using time, storage or stake in order to select blocks to be appended to the chain. As a drawback it makes it difficult for the application developer to choose the right blockchain to support their applications. In particular, the scalability and performance one can obtain from a specific blockchain is typically unknown. The claimed results are often obtained in isolation by the developers of the blockchain themselves. The experimental conditions corresponding to these results are generally missing and the lack of details make these results irreproducible.
Federico Carrozzino, Marco Fiore, Marina Mongiello
Blockchain technology is a Distributed Ledger Technology mainly used to store information in an immutable and secure way, but scalability and throughput issues are major challenges. Integration of the NoSQL paradigm within a Blockchain pipeline enhances throughput and scalability, and it can handle both on-chain and off-chain data. This work aims to study which approaches are currently used to integrate a NoSQL database in a Blockchain architecture, how the advantages of both technologies can be exploited to enhance the system's capabilities, and to propose a novel hybrid architecture that mixes Blockchain and NoSQL characteristics.