Igor Y. Mazurok, Yevhen Leonchyk, Sergii Grybniak, Alisa Vorokhta · 5 authors
Decentralized platforms like blockchain have been attracting significant attention in recent years, especially in the context of financial and payment systems. They are designed to provide a transparent, secure, and reliable environment for digital transactions without the need for a central authority. The core of a decentralized platform like blockchain is a consensus layer that allows all participants (called Workers), who properly operate and follow all network protocols and have access to the same state of the distributed ledger, to coordinate their actions and arrive at the same decisions. However, some Workers may be temporarily offline attheir own discretion, without any confirmation, or their work may be faulty due to technical circumstances, resulting in unpredictablebehavior. The goal of this article is to present an approach for multi-objective optimizing of Byzantine fault tolerance (BFT)-basedconsensus protocols, to reduce the impact on the network of faulty participants. Two criteria were considered â minimization of thenumber of sent service messages, and maximization of the mathematical expectation of the number of produced blocks. The result isa method to determine the optimal committee size and distribution of Workers, depending on their total number in the network andthe expected proportion of Byzantine faulty nodes. All protocol amendments presented in this work are tested with corresponding simulation models and have demonstrated notable enhancements in the performance of the system and decreased the load on network nodes. These improvements will be implemented to the consensus protocol Gozalandia on the Waterfall platform, enhancing itsoverall reliability, performance, and security. In addition, the presented optimizing algorithm can be applied to a wide range of consensus protocols in blockchains, where blocks must be signed by randomly selected committees to confirm their validity.
Consensus mechanisms play a critical role in blockchain networks, ensuring that all participants agree on the state of the distributed ledger. However, existing consensus mechanisms have limitations in terms of efficiency, security, and decentralization. In this research paper, we propose a Hybrid Consensus Mechanism (HCM) that combines the advantages of Delegated Proof of Stake (DPoS), Practical Byzantine Fault Tolerance (PBFT), and Proof of Elapsed Time (PoET) to address these limitations. HCM uses a set of trusted validators (delegates) similar to DPoS, who participate in a PBFT-like consensus protocol to reach agreement on the state of the ledger. PoET is used to randomly select the leader for each consensus round, preventing the concentration of power. HCM also introduces a dynamic delegation mechanism and sharding technique to enhance fairness, resilience, and scalability in blockchain networks. We provide detailed technical insights, backed by underlying data, to illustrate the effectiveness of HCM in achieving efficient and secure consensus.
Given that reliable cloud quantum computers are becoming closer to reality, the concept of delegation of quantum computations and its verifiability is of central interest. Many models have been proposed, each with specific strengths and weaknesses. Here, we put forth a new model where the client trusts only its classical processing, makes no computational assumptions, and interacts with a quantum server in a single round. In addition, during a set-up phase, the client specifies the size $n$ of the computation and receives an untrusted, off-the-shelf (OTS) quantum device that is used to report the outcome of a single measurement. We show how to delegate polynomial-time quantum computations in the OTS model. This also yields an interactive proof system for all of QMA, which, furthermore, we show can be accomplished in statistical zero-knowledge. This provides the first relativistic (one-round), two-prover zero-knowledge proof system for QMA. As a proof approach, we provide a new self-test for n EPR pairs using only constant-sized Pauli measurements, and show how it provides a new avenue for the use of simulatable codes for local Hamiltonian verification. Along the way, we also provide an enhanced version of a well-known stability result due to Gowers and Hatami and show how it completes a common argument used in self-testing.
As coin-based rewards dwindle, transaction fees play an important role as mining incentives in Bitcoin. In this paper, we propose a novel mechanism called Efficient Dynamic Transaction Storage (EDTS) for dynamically allocating transactions among blocks to achieve efficient storage utilization. By leveraging a combination of Cuckoo Filter and Dynamic Transaction Storage (DTS) strategies, EDTS is able to improve the scalability while remaining sustainable even after the Bitcoin enters a transaction-fee regime. In addition to preventing deviant mining behaviors under the transaction-fee regime, EDTS can also provide differentiated transmission priorities based on transaction fees while allowing the investors to engage in pledging more transaction fees. In EDTS, we applied the multi-objective optimization algorithm U-NSGA-III to find the best DTS strategy and its corresponding attributes. Experimental results show that the EDTS mechanism together with the optimized DTS strategy can achieve a throughput of 325.3 TPS. The experimental results reveal that the scalability improvement of EDTS is superior to the performance of Bitcoin NG, which is the best known on-chain scaling solution, while maintaining the sustainability under the transaction-fee regime.
Miguel Pincheira, Elena Donini, Massimo Vecchio, Raffaele Giaffreda
Blockchain is currently a core technology for developing new types of decentralized applications. With the unique properties of blockchain, unique challenges and characteristics are introduced to the system. Among these characteristics, the infrastructure costs and benefits of the system are critical to evaluate the feasibility of any system and have yet to be addressed in the current literature. This work presents a framework for evaluating blockchain applicationsâ infrastructure costs and benefits. The framework includes a taxonomy to classify the related transactions, a model to evaluate the infrastructure costs and benefits in applications using public or private blockchains, and a methodology to guide the use of the model. The model is based on simple parameters that describe the systems, and the methodology helps to identify and estimate these parameters at any stage of the application life cycle. We quantitatively analyze three real use cases to demonstrate the frameworkâs merit. The analyses highlight the modelâs accuracy by achieving the same results presented in the use cases. Furthermore, the use-case analyses emphasize the frameworkâs potential to evaluate different scenarios across the entire life cycle of blockchain-based applications.
With the advancement of cloud computing technologies, it is necessary to maintain quality of service, for which service level agreements (SLAs) are one of the ways to improve this. A significant part of revenue will be contributed by the use of on demand resources (compute, network or storage) provided by this cloud service providers (CSP). Service level agreement (SLA) plays a key role in maintaining quality of services (QoS) of these on demand resources. The CSP enforces the SLA, by utilizing machine-generated logs to monitor machine performance. Additionally, some consumers may monitor resource performance themselves to ensure it meets their standards. This approach not only leads to traction between both CSP and cloud service consumers (CSC), but also leads to a duplication of the effort. The aim of this work is to create a system that is distributed in nature and could be trusted by both CSP and the consumer. The paper provides solution using a public blockchain and log based algorithm that evaluates resource performance based on several SLA criteria accepted by the CSP and consumers. If the systemâs performance falls below a certain level, the CSC will be intimated through logs. This motivates the consumer to spend more money on the resources and compels the CSP to keep the number of SLA violations to a minimal. A web application with a blockchain as the back-end is used to monitor SLA violations and the compensation procedure. Finally, a multi-node ethereum blockchain network is used to conduct a performance analysis of the suggested solution.
Permissioned blockchains are being widely applied to solve the trust problem in enterprise collaboration. However, most of these systems suffer from low throughput and flexibility lacking issues. In this paper, we present a blockchain system SChain with scalable concurrent execution based on a flexible architecture. SChain separates the functionality of a complete "node" into three sub-functions and assigns them to different peers within every organization. Then each organization can scale each sub-function flexibly with no need for negotiation between organizations. Based on this architecture, SChain explores scalable concurrent execution from two levels. First, SChain takes the advantage of multiple peers to execute transactions collectively, while promising they make the same results as one peer does serially. Second, SChain enables concurrent transaction execution across blocks to utilize the resources of peers fully, breaking up the block-by-block process manner, based on a pipelined workflow. The extensive evaluation results demonstrate that SChain significantly outperforms the serial execution and other competing systems-level approaches.
Todayâs organizations utilize a plethora of heterogeneous and autonomous DBMSes, many of those being spread across different geo-locations. It is therefore crucial to have effective and efficient cross-database query processing capabilities. We present XDB, an efficient middleware system that runs cross-database analytics over existing DBMSes. In contrast to traditional query processing systems, XDB does not rely on any mediating execution engine to perform cross-database operations (e.g., joining data from two DBMSes). It delegates an entire query execution including cross-database operations to underlying DBMSes. At its core, it comprises an optimizer and a delegation engine: the optimizer rewrites cross-database queries into a delegation plan, which captures the semantics as well as the mechanics of a fully decentralized query execution; the delegation engine then deploys the plan to the underlying DBMSes via their declarative interfaces. Our experimental study based on the TPC-H benchmark data shows that XDB outperforms state-of-the-art systems (Garlic and Presto) by up to 6Ă in terms of runtime and up to 3 orders of magnitude in terms of data transfer.
Blockchain is a decentralized, shared ledger that aggregates blocks of data in a factual data structure in chronological order using a chain structure. Two hundred sixty thousand tokens, or 98% of the around 2.5 million smart contracts in Ethereum network, are ERC-20 tokens. The ERC20 standard specifies constructors for token contracts that establish and initialize the contract state. The Ethereum wallet and Ethereum decentralized, centralized applications can access tokens through these standard interfaces. Security vulnerabilities in ERC-20 have drawn a lot of attention lately in recent years. This paper summarizes some basic security vulnerabilities and suggests avoiding multiple withdrawal attacks. Tokens can be used to support dApps, access blockchain services, trade, and obtain voting rights. Various tokens exist depending on their properties and use cases, including governance, utility, security, transaction, and platform tokens. Tokens can be sorted as fungible tokens and non-fungible tokens. Tokens that can be fungible are identical, divisible, and can be instead of money. Non-fungible tokens have a single owner and are unique.
Gartnerâs hype cycle of technology famously progresses from the âpeak of inflated expectationsâ to the âplateau of productivityâ via the âtrough of disillusionmentâ. Accounting researchers and practitionersâlike researchers and practitioners in many other fieldsâhave jumped onto the blockchain bandwagon for fear of missing out on what has been hailed as a world changing technology. Unfortunately, there is a pervasive lack of understanding of what blockchain is, and misconceptions about what it can do. A fundamental problem is that blockchain was derived from bitcoin and there is a great deal of difficulty in defining what blockchain is, and how suitable the methodology for a trustless, public cybercurrency application is to a public blockchain between trusted partners. It is time, we believe, to look at blockchain in accounting with more objectivity. We undertake a detailed exploration of blockchain and identify several key factors that will defines the uses of this technology, namely, the distinction between public and private blockchains and the importance of processing costs as a validating mechanism.
Novak BoĆĄkov, Ari Trachtenberg, David Starobinski
The problem of data synchronization arises in networked applications that require some measure of consistency. Indeed data synchronization approaches have demonstrated a significant potential for improving performance in various applications ranging from distributed ledgers to fog-enabled storage offloading for IoT. Although several protocols for data sets synchronization have been proposed over the years, there is currently no widespread utility implementing them, unlike the popular Rsync utility available for file synchronization. To that end, we describe a new middleware called GenSync that abstracts the subtleties of the state-of-the-art data synchronization protocols, allows users to choose protocols based on a comparative evaluation under realistic system conditions, and seamlessly integrate protocols in existing applications through a public API. We showcase GenSync through a case study, in which we integrate it into one of the world's largest wireless emulators and compare the performance of its included protocols.
Non-fungible tokens (NFTs) have been attracting the interest of both technical and non-technical parties, including collectors and traders, among others. The number of transactions in NFTs surpassed $50 billion in 2022. Blockchain technology's advantages as a distributed, immutable, and transparent database make it ideal for verifying the ownership of digital goods created by their producers. On the other hand, high computation and transaction costs are known disadvantages of public blockchain networks like Ethereum V1, used in NFT marketplaces. To address these inefficiencies, other public blockchain systems have emerged as replacements for NFT marketplaces, each with its own unique properties. When planning such an NFT exchange, it is vital, but not trivial, to select the most appropriate public blockchain platform. In this work, we make two contributions to support this decision. In this paper, we present IntelliChain , a self-adaptive framework that can predict the best optimal transaction fees (also known as a gas fee) for blockchain to reduce the errors and also an ability to switch the public blockchain-based dynamic needs such as transaction fees and stability of the network.
Everything is digitalized in the digital age, including the SSLC, HSC, and academic certificates, which are sent to students and digitalized at educational establishments. Students have difficulty maintaining their degree credentials. Organizations and institutions find it difficult and time-consuming to verify certificates. By storing the certificate in the Blockchain system, our proposal will aid in its security. Advanced certificates are first made from the paper certificates. The certificate's hash code esteem is made utilizing the turbulent calculation. From that point onward, the confirmations are saved in Blockchain. Moreover, these certificates are confirmed through the versatile application.
Blockchain technology has gained momentum due to its immutability and transparency. Several blockchain platforms, each with different consensus protocols, have been proposed. However, choosing and configuring such a platform is a non-trivial task. Numerous benchmarking tools have been introduced to test the performance of blockchain solutions. Yet, these tools are often limited to specific blockchain platforms or require complex configurations. Moreover, they tend to focus on one-off batch evaluation models, which may not be ideal for longer-running instances under continuous workloads. In this work, we presentBlockCompass, an all-inclusive blockchain benchmarking tool that can be easily configured and extended. We demonstrate howBlockCompasscan evaluate the performance of various blockchain platforms and configurations, including Ethereum Proof-of-Authority, Ethereum Proof-of-Work, Hyperledger Fabric Raft, Hyperledger Sawtooth with Proof-of-Elapsed-Time, Practical Byzantine Fault Tolerance, and Raft consensus algorithms, against workloads that continuously fluctuate over time. We show how continuous transactional workloads may be more appropriate than batch workloads in capturing certain stressful events for the system. Finally, we present the results of a usability study about the convenience and effectiveness offered byBlockCompassin blockchain benchmarking.
Kashif Mehboob Khan, Aabira Fahim, Darakhshan M. Saleem, Marvi Jokhio
With the emerging employment of blockchains in different fields a need for blockchain intercommunication has arisen but there is no set standard yet for blockchain development, adoption and implementation due to which its interoperability has become a challenge. Interoperability refers to the mechanism of exchange and utilization of information between two software or computer systems etc. In blockchain, interoperability is the process of data creation, transfer and storage between two blockchains or blockchain applications. Blockchain interoperability is complex as every blockchain may have a different implementation platform and protocol for consensus mechanism. Bringing together two different blockchains and enabling communication between them without modifying their underlying implementation structure is a challenge today. There has been ongoing research in this domain to achieve interoperability in blockchains effectively. Its importance is evident from the fact that blockchain interoperability is vital for promoting scalability which is another research challenge presently. Apart from this, blockchain interoperability also promotes data privacy, application flexibility and portability and provides new opportunities in business. In this paper we have discussed in detail the three approaches and the solutions they provide for implementing blockchain interoperability. An empirical based analysis has been used to strengthen our methodology, which takes into consideration the selection of known & established blockchain network with state-of-the-art tools and technology. In order to have seamless communication across different chains, light clients (representing the respective chain) have been enabled to store each otherâs information such as protocol version etc. In this way, the handshake between both the chain has resulted in a successful IBC (Inter Blockchain Communication) inside the Cosmos environment. It is concluded that although blockchain interoperability is being implemented today, this implementation is highly restricted to specific organizations or software tools. Moreover interoperability between two different blockchains is still an ongoing challenge. This study will assist the future work in the domain of blockchain interoperability as it makes the understanding and implementation of blockchain interoperability easier.
Blockchain is one of the most recent disrupting technologies. Since Bitcoin emerged as its initial application, many blockchain projects arose offering different features for general and domain specific scenarios. In turn, Blockchain platforms work as isolated environments and they do not support interaction (i.e. interoperability) between each other.During the last years, some academic and industry efforts were performed in order to achieve interoperability between blockchain platforms. However, these efforts solve specific use cases and do not provide a general interoperability solution. In order to organize existing work in the area, this paper provides a feature-based classification framework based on 16 key interoperability features, that enabled the classification of 65 academic papers in three categories and six subcategories.The results show that nowadays research is focused on public interoperability, while private and public-to-private interoperability are still on their first steps. Based on these results, this work also discusses nowadays blockchain interoperability landscape, identifies challenges, and suggests future research directions.
Blockchain provides trustworthy properties such as decentralization, traceability, and transparency, and has been applied in various fields. Given the complexity of guaranteeing the accuracy of the input data, erroneous data may be stored on the blockchain, making it hard to modify. As an effective solution, redactable blockchain allows on-chain data to be modified by introducing a chameleon hash function with a trapdoor, which enables on-chain erroneous data to be corrected. However, existing redactable blockchain solutions often require trusted third parties, have huge overhead, or lack effective accountability mechanisms to meet data security needs. Therefore, this paper proposes a secure, efficient and accountable data management scheme based on redactable blockchain. To cope with the possible frequent editing needs, we design an efficient and accountable distributed trapdoor recovery mechanism that reliably maintains data security while avoiding the security risks associated with centralized management. Various information during the trapdoor management process is also recorded on the chain as the basis for implementing accountability mechanisms. In addition, the one-time trapdoor technology allows the blockchain system to reduce the maintenance complexity of the system by eliminating the need to frequently update the system parameters when partial trapdoor information needs to be published. Theoretical and experimental results show that our scheme can achieve an efficient accountability mechanism while modifying the data on the chain at low cost.
Cezara DrÄgoi, Constantin Enea, Srinidhi Nagendra, Mandayam Srivas
Large-scale, fault-tolerant, distributed systems are the backbone for many critical software services. Since they must execute correctly in a possibly adversarial environment with arbitrary communication delays and failures, the underlying algorithms are intricate. In particular, achieving consistency and data retention relies on intricate consensus (state machine replication) protocols. Ensuring the reliability of implementations of such protocols remains a significant challenge because of the enormous number of exceptional conditions that may arise in production. We propose a methodology and a tool called Netrix for testing such implementations that aims to exploit programmer's knowledge to improve coverage, enables robust bug reproduction, and can be used in regression testing across different versions of an implementation. As evaluation, we apply our tool to a popular proof of stake blockchain protocol, Tendermint, which relies on a Byzantine consensus algorithm, a benign consensus algorithm, Raft, and BFT-Smart. We were able to identify 4 deviations of the Tendermint implementation from the protocol specification and check their absence on an updated implementation. Additionally, we were able to reproduce 4 previously known bugs in Raft.
Faton Kabashi, Halil Snopçe, Azir Aliu, Artan Luma · 5 authors
Blockchain is one of the most current technologies in recent times. Many Institutions in Higher Education aim to implement it for the management of certificates, the assessment of professional skills of students, the registration of non-academic activities, the distribution of educational resources, the management of academic degrees, the transfer of fees and credits, etc. The main purpose of this paper is to review the research carried out in relation to blockchain technology in Higher Education, specifically in relation to its applications in education, the main benefits, challenges, implementation which will help us find gaps and research in the future. To make this review, we extracted 763 articles from the IEEE Explore, ACM and Google Scholar databases during the years 2018â2022. After a detailed review based on the defined inclusion and exclusion criteria, we reviewed 33 papers.
Accounting practices are based on their underlying accounting principles, and currently, the Double-Entry Accounting (DEA) is used in both manual and computer-based Accounting Information Systems (AIS). DEA has been used for centuries according to the rules that were set when it was invented. At this stage, there is no further room to expand its functionality, but a logical expansion of DEA is possible. This new dimension is called Triple-Entry bookkeeping in which a third accounting entry is passed in a shared ledger that is distributed in nature and publicly visible. Similarly, Blockchain is a form of shared ledger distributed on a peer-to-peer network, and all transactions in the ledger are available to view. Blockchain emerged in 2008 as an underlying record-keeping and data storage technology for Bitcoin. It is believed that TEA is the idea behind the Blockchain. In this research study, we review the evolution of TEA and Blockchain from the existing academic literature, and the findings of the study will deepen the researchers' understanding of these two concepts and help them identify new opportunities.