Consortium blockchains have attracted considerable interest from academia and industry due to their low-cost installation and maintenance. However, typical consortium blockchains can be easily attacked by colluding block validators because of the limited number of miners in the systems. To address this problem, in this paper, we propose a novel block validation framework to enhance blockchain security. In the framework, the block validations are assisted and implemented by various lightweight nodes, e.g., edge devices, in addition to the typical blockchain miners. This improves the blockchain security but can cause an increased block validation delay and, thereby, reduced blockchain throughput. To tackle this challenge, we propose an effective method to select lightweight nodes based on their computing powers to maximize the blockchain throughput, and prove the uniqueness of the optimal nodes selection strategy. Security analysis and simulation results from the deployed consortium blockchain platform show that the proposed framework achieves higher throughput and security than the existing consortium blockchain models.
The e-book services we use today have a serious drawback in that we will no longer be able to read the books we have purchased when the service is terminated. One way to solve this problem is to build a decentralized system that does not depend on a specific company or organization by combining smart contracts running on the Ethereum blockchain and distributed storage such as an IPFS. However, a simple combination of existing technologies does not make the stored e-book data persistent, so the risk of purchased e-books becoming unreadable remains. In this paper, we propose a decentralized distributed storage called d-book-repository, which has both access management function and data durability for purchased e-books. This system uses NFTs as access rights to realize strict access control by preventing clients who do not have NFTs from downloading e-book data. In addition, e-book data stored on storage nodes in the distributed storage is divided into shards using Reed–Solomon codes, and each storage node stores only a single shard, thereby preventing the creation of nodes that can restore the entire content from locally stored data. The storage of each shard is not handled by a single node but by a group of nodes, and the shard is propagated to all nodes in the group using the gossip protocol, where erasure codes are utilized to increase the resilience against node departure. Furthermore, an incentive mechanism to encourage participation as a storage node is implemented using smart contracts. We built a prototype of the proposed system on AWS and evaluated its performance. The results showed that both downloading and uploading 100 MB of e-book data (equivalent to one comic book) were completed within 10 s using an instance type of m5.xlarge. This value is only 1.3 s longer for downloading and 2.2 s longer for uploading than the time required for a simple download/upload without access control, confirming that the overhead associated with the proposed method is sufficiently small.
With the increasing popularization and application of the smart grid, the harm of the data silo issue in the smart grid is more and more prominent. Therefore, it is especially critical to promote data interoperability and sharing in the smart grid. Existing data-sharing schemes generally lack effective incentive mechanisms, and data holders are reluctant to share data due to privacy and security issues. Because of the above issues, a dynamic incentive mechanism for smart grid data sharing based on evolutionary game theory is proposed. Firstly, several basic assumptions about the evolutionary game model are given, and the evolutionary game payoff matrix is established. Then, we analyze the stabilization strategy of the evolutionary game based on the payoff matrix, and propose a dynamic incentive mechanism for smart grid data sharing based on evolutionary game theory according to the analysis results, aiming to encourage user participation in data sharing. We further write the above evolutionary game model into a smart contract that can be invoked by the two parties involved in data sharing. Finally, several factors affecting the sharing of data between two users are simulated, and the impact of different factors on the evolutionary stabilization strategy is discussed. The simulation results verify the positive or negative incentives of these parameters in the data-sharing game process, and several factors influencing the users’ data sharing are specifically analyzed. This dynamic incentive mechanism scheme for smart grid data sharing based on evolutionary game theory provides new insights into effective incentives for current smart grid data sharing.
Mohammad Masoud, Yousef Jaradat, Ahmad Manasrah, Mohammad Alia · 6 authors
This work carried out a measurement study of the Ethereum Peer-to-Peer (P2P) network to gain a better understanding of the underlying nodes. Ethereum was applied because it pioneered distributed applications, smart contracts, and Web3. Moreover, its application layer language “Solidity” is widely used in smart contracts across different public and private blockchains. To this end, we wrote a new Ethereum client based on Geth to collect Ethereum node information. Moreover, various web scrapers have been written to collect nodes’ historical data from the Internet Archive and the Wayback Machine project. The collected data has been compared with two other services that harvest the number of Ethereum nodes. Our method has collected more than 30% more than the other services. The data trained a neural network model regarding time series to predict the number of online nodes in the future. Our findings show that there are less than 20% of the same nodes daily, indicating that most nodes in the network change frequently. It poses a question of the stability of the network. Furthermore, historical data shows that the top ten countries with Ethereum clients have not changed since 2016. The popular operating system of the underlying nodes has shifted from Windows to Linux over time, increasing node security. The results have also shown that the number of Middle East and North Africa (MENA) Ethereum nodes is neglected compared with nodes recorded from other regions. It opens the door for developing new mechanisms to encourage users from these regions to contribute to this technology. Finally, the model has been trained and demonstrated an accuracy of 92% in predicting the future number of nodes in the Ethereum network.
The social network Twitter possesses a key characteristic: it is centralized, allowing Twitter Corporation to control data substitution and set moderation rules. However, this issue can only be resolved through the complete decentralization of the platform. To achieve this, blockchain technology is crucial as it enables the operation of decentralized applications with smart contracts serving as the foundation for system-user interaction. In this paper, we propose the minimum viable implementation of a similar social network called Brain Logger, which stores all necessary data in the NEAR blockchain network. Introducing a small fee for modifying data on the network ensures a solution to the aforementioned problems. The implementation includes a smart contract for blockchain networks and a web application frontend. The smart contract was developed using the NEAR software development kit in Rust, while the frontend was created in JavaScript using the React framework and Redux for local data storage. The code can be accessed on Github.
Over the past few years, there has been a profound evolution in decentralization methodologies, owing largely to the emergence of novel decentralized technologies like blockchain. In the realm of online social media, a paradigm shift has been suggested with the introduction of blockchain-based online social media (BOSM), heralding a potential future for social media platforms wherein users are duly rewarded for their valuable contributions. Despite the widespread adoption of these platforms by millions of users, it is crucial to acknowledge that their decentralization remains incomplete. One prevailing issue within existing blockchain systems resides in the vulnerability of the Delegated Proof of Stake (DPoS) consensus algorithm, which is susceptible to manipulation by the few selected nodes. Anticipating the demands of the forthcoming generation of social media, the pivotal imperative lies in establishing decentralization as its foundational hallmark. In this paper, we present Sociala, an incentivized blockchain-based framework tailored for writers. To effectively address the pitfalls of centralization and minimize the likelihood of nefarious node selection, we proffer an enhanced multi-step DPoS consensus algorithm, which is referred as modified DPoS (mDPoS). This advanced algorithm embraces both the tenets of randomness and diversity, coupled with the inclusion of input from general users, culminating in fortified system stability.
Blockchain technologies have been used to facilitate Web 3.0 and FinTech applications. However, conventional blockchain technologies suffer from long transaction delays and low transaction success rates in some Web 3.0 and FinTech applications such as Supply Chain Finance (SCF). Blockchain sharding has been proposed to improve blockchain performance. However, the existing sharding methods either use a static sharding strategy, which lacks the adaptability for the dynamic SCF environment, or are designed for public chains, which are not applicable to consortium blockchain-based SCF. To address these issues, we propose an adaptive consortium blockchain sharding framework named ACSarF, which is based on the deep reinforcement learning algorithm. The proposed framework can improve consortium blockchain sharding to effectively reduce transaction delay and adaptively adjust the sharding and blockout strategies to increase the transaction success rate in a dynamic SCF environment. Furthermore, we propose to use a consistent hash algorithm in the ACSarF framework to ensure transaction load balancing in the adaptive sharding system to further improve the performance of blockchain sharding in dynamic SCF scenarios. To evaluate the proposed framework, we conducted extensive experiments in a typical SCF scenario. The obtained experimental results show that the ACSarF framework achieves a more than 60% improvement in user experience compared to other state-of-the-art blockchain systems.
The emergence of the World Wide Web has revolutionized online communication, aiming to achieve global information sharing and communication. However, the current Web 2.0 architecture, which relies on centralized platforms, presents limitations such as restricted user rights, data privacy concerns, and dependence on centralized institutions. Web3, as a concept describing the next evolutionary stage of the internet, offers a solution to these issues by reshaping the internet infrastructure. Web3 provides a foundation for autonomous digital experiences and drives the advancement of the digital economy. This paper offers a thorough exploration of Web3, covering its key technologies, applications, challenges, and opportunities. We begin by introducing the core technologies behind Web3, followed by an exploration of its prominent applications. Finally, we analyze the challenges faced by Web3 and discuss potential research opportunities to address these challenges in the future. In summary, this study comprehensively elaborates on Web3 and lays a solid foundation for subsequent research work, encouraging researchers to explore new frontiers.
Since the introduction of the first cryptocurrency, Bitcoin, in 2008, the gain in popularity of distributed ledger technologies (DLTs) has led to an increasing demand and, consequently, a larger number of network participants in general. Scaling blockchain-based solutions to cope with several thousand transactions per second or with a growing number of nodes has always been a desirable goal for most developers. Enabling these performance metrics can lead to further acceptance of DLTs and even faster systems in general. With the introduction of directed acyclic graphs (DAGs) as the underlying data structure to store the transactions within the distributed ledger, major performance gains have been achieved. In this article, we review the most prominent directed acyclic graph platforms and evaluate their key performance indicators in terms of transaction throughput and network latency. The evaluation aims to show whether the theoretically improved scalability of DAGs also applies in practice. For this, we set up multiple test networks for each DAG and blockchain framework and conducted broad performance measurements to have a mutual basis for comparison between the different solutions. Using the transactions per second numbers of each technology, we created a side-by-side evaluation that allows for a direct scalability estimation of the systems. Our findings support the fact that, due to their internal, more parallelly oriented data structure, DAG-based solutions offer significantly higher transaction throughput in comparison to blockchain-based platforms. Although, due to their relatively early maturity state, fully DAG-based platforms need to further evolve in their feature set to reach the same level of programmability and spread as modern blockchain platforms. With our findings at hand, developers of modern digital storage systems are able to reasonably determine whether to use a DAG-based distributed ledger technology solution in their production environment, i.e., replacing a database system with a DAG platform. Furthermore, we provide two real-world application scenarios, one being smart grid communication and the other originating from trusted supply chain management, that benefit from the introduction of DAG-based technologies.
Bitcoin, the most valuable and energy-consuming cryptocurrency, has recently been at the center of a heated debate over its environmental impact. This controversy has caught the public’s attention, prompting us to investigate the energy consumption of Bitcoin. In this paper, we have conducted a review of the literature on various aspects of Bitcoin mining, including its mechanisms, energy consumption, mining sites, and the potential for renewable energy use. Our findings reveal that the power consumption of Bitcoin is bound to increase with the continued adoption of the proof-of-work (PoW) consensus algorithm. Nonetheless, the growing availability of affordable renewable energy sources worldwide brings hope that Bitcoin mining will shift towards cleaner energy in the near future.
Guocheng Zhu, Debiao He, Haoyang An, Min Luo · 5 authors
Abstract After the Ethereum DAO attack in 2016, which resulted in significant economic losses, blockchain governance has become a prominent research area. However, there is a lack of comprehensive and systematic literature review on blockchain governance. To deeply understand the process of blockchain governance and provide guidance for the future design of the blockchain governance model, we provide an in-depth review of blockchain governance. In this paper, first we introduce the consensus algorithms currently used in blockchain and relate them to governance theory. Second, we present the main content of off-chain governance and investigate two well-known off-chain governance projects. Third, we investigate four common on-chain governance voting techniques, then summarize the seven attributes that the on-chain governance voting process should meet, and finally analyze four well-known on-chain governance blockchain projects based on the previous research. We hope this survey will provide an in-depth insight into the potential development direction of blockchain governance and device future research agenda.
Bitcoin was launched over a decade ago and has made an increasing impact on the world’s financial order, which has attracted the attention of researchers all over the world. The Bitcoin system runs on a dynamic P2P network, containing tens of thousands of nodes, including reachable nodes and unreachable nodes. In this article, a detection system, BNS (Bitcoin Network Sniffer), which could collect as many Bitcoin nodes as possible is proposed. For reachable nodes, the authors designed an algorithm, BRF (Bitcoin Reachable-Nodes Finding), based on node activity evaluation which reduces the nodes to be detected and greatly shortens the detection time. For unreachable nodes, the authors trained a decision tree model, BUF (Bitcoin Unreachable-Nodes Finding), to identify unreachable nodes based on attribute features from a large number of node addresses. Experiments showed that BNS discovered an average of 1093 more reachable nodes (6.4%) and 662 more unreachable nodes (2.3%) than the well-known website “Bitnodes” per day. It showed better performance in total nodes and efficiency. Based on the experimental results, the authors analyzed the real network size, node “churn”, and geographical distribution.
Saidu Sokoto, Michał Król, Vladimir Stanković, Étienne Rivière
Distributed Hash Tables (DHTs) serve as the backbone of numerous modern decentralized systems like the InterPlanetary File System (IPFS) and Ethereum. As these systems evolve and expand, there is a growing need to enhance and optimize their underlying network support. In response to these challenges, we embark on the development of a new class of DHTs, marked by efficiency, security, and suitability for real-world deployments. We achieve this by making changes in the routing procedures, incorporating latency-aware routing, and harnessing recent hardware advancements.
A system of zero-knowledge proofs on graph signatures has been proposed, where a graph can be signed, and the owner of the graph signature can prove a graph relation such as the connectivity and isolation of any two vertexes on the graph without disclosing all information about the graph. The correctness of the graph information is guaranteed by the signature. One of the applications is a virtualized infrastructure, where an infrastructure provider manages a distributed system, and each tenant is allocated a specific portion of this infrastructure for use. Tenants need to check with the provider that their resources are properly connected (connectivity) and that their resources are properly separated from the resources of other tenants (isolation). On the other hand, the provider cannot simply disclose the entire infrastructure topology to each tenant. Using the zero-knowledge proof system on graph signatures, both requirements can be addressed. Previously, an efficient zero-knowledge proof system on graph signatures using a bilinear-map accumulator has been proposed, where the verification time and the size of the proof data do not depend on the number of graph vertexes and edges. However, this system has two problems. First, since the proof does not include labels, it is not possible to prove the connectivity considering network bandwidth and cost. Second, since it assumes undirected graphs, it cannot handle applications on directed graphs such as network flows. In this paper, we extend the previous system and propose a zero-knowledge proof system of the connectivity for directed graphs where each edge has labels. We implemented our system on a PC using a pairing library and evaluate it by measuring the processing times. Compared to the conference version of this paper, we show the formal definitions and the security proofs of our proposed system, and add implementation-based evaluations reflecting the application to the virtualized infrastructure.
Web3, the next generation of the Internet, represents a decentralized and democratized web. Although it has garnered significant public interest and found numerous real-world applications, there is a limited understanding of people's perceptions and experiences with Web3. In this study, we conducted an empirical study to investigate the categories of Web3 applications and their popularity, as well as the potential challenges and opportunities within this emerging landscape. Our research was carried out in two phases. In the first phase, we analyzed 200 popular Web3 projects associated with 10 leading Web3 venture capital firms. In the second phase, we collected and examined code-related data from GitHub and market-related data from blockchain browsers (e.g., Etherscan) for these projects. Our analysis revealed that the Web3 ecosystem can be categorized into two groups, i.e., Web3 infrastructure and Web3 applications, with each consisting of several subcategories or subdomains. We also gained insights into the popularity of these Web3 projects at both the code and market levels and pointed out the challenges in the Web3 ecosystem at the system, developer, and user levels, as well as the opportunities it presents. Our findings contribute to a better understanding of Web3 for researchers and developers, which in turn promotes further exploration and advancement in this innovative field.
The promise of a fully decentralized web is too big to ignore. The bridging of Web2 and Web3 infrastructure is crucial for realizing this decentralized future. However, the current computational and storage demands in blockchain systems often result in challenges for users, leading to reliance on centralized endpoint API services in Web3 application designs. This dependence raises concerns about privacy, availability, and security. This doctoral study aims to enhance the accessibility and decentralization of blockchains, especially by facilitating the participation of resource-constrained devices such as smartphones and browsers. The goal is to facilitate the widespread adoption of decentralized systems that are secure, reliable, and scalable.
Opportunistic networks (OppNets) are usually a set of smart, wearable, and portable devices or entities with mobility that connect wirelessly without requiring infrastructure. Such a network is of great importance in data transmission, particularly in incidents and disasters, whether man-made or natural. However, message integrity and confidentiality are of concern when it deals with vital and physiological data transmission with strict privacy regulations. In this work, we offered a structure to classify messages based on their priority in different queues. Furthermore, due to the decentralized architecture of OppNets, we proposed a blockchain-based structure for providing security for high-priority messages. It contains three sequences of functional blocks with a light and simplified implementation that makes it suitable for battery-powered wearable devices that are limited in energy consumption and computational units. The simulation results showed that by increasing the number of nodes in the network, the average of the changes in block sizes are neglectable which addresses the computation bottleneck. Furthermore, we analyzed the performance of the proposed structure in terms of message delivery and network overhead compared with Epidemic and Prophet routing algorithms. These results indicated advancing the overall performance of the proposed algorithm.
Blockchains are becoming increasingly important in today’s Internet, enabling large-scale decentralized applications with strong security and transparency properties. In a blockchain system, participants maintain and update the server-side state of an application by appending data as blocks onto an immutable, distributed ledger through a consensus protocol within a peer-to-peer network. There has been a significant increase in profit in mining blocks. For instance, Bitcoin miners currently receive over USD 200,000 per mined block. An essential determinant of these rewards is the time it takes to disseminate newly mined blocks across the network. This paper addresses the challenge of optimizing mining rewards by exploring topology design in a wide-area blockchain network utilizing a Proof-of-Work consensus protocol. We show that under low block times, the geographical location of a miner critically impacts the number of successful blocks mined by the miner. We also show that a miner may improve its success rate by increasing its connectivity to the network. However, contrary to the general wisdom that a faster network is always better for a miner, we show that increasing network connectivity (e.g., by adding more neighbors) is beneficial to a miner only up to a point after which the miner’s rewards degrade. This is because when a miner improves its connectivity, it inadvertently also aids other miners in increasing their connectivity. We also present a network-level collusion attack in which a miner can increase its block success rate by becoming part of a tightly connected cluster. Here too, we observe that the mining gains obtained increase with cluster size only up to a point, and decrease thereafter. Our findings highlight that the network topology is a key variable affecting miner performance in PoW blockchains that must not be overlooked. We demonstrate our observations via detailed simulations modeled using real-world measurement data.
Blockchain technology contributes to achieving the Sustainable Development Goals. Education for sustainable development (ESD) is UNESCO’s education sector response to the urgent and dramatic challenges the planet faces. The traditional way of donating money to charitable causes, such as education, has been through centralized methods and organizations that lack transparency, and donors often do not have a clear understanding of how their contributions are being utilized. Blockchain technology, particularly, platforms like Ethereum and Polygon, has the potential to address the issues associated with traditional donation systems. This paper proposes a decentralized web3 application that utilizes blockchain technology to enhance transparency and efficiency in educational donations in the context of sustainable development. The platform leverages decentralized protocols and smart contracts to ensure secure and transparent transactions, enabling donors to track the utilization of their contributions and ensuring their funds reach their intended beneficiaries. This paper discusses the design and implementation of the platform, highlighting its features and potential for transforming the landscape of charitable donations. This software application can be used in education, and a demo plus some scenarios/work cases are presented/analyzed. The main results and contributions open other future research directions for not only authors.
This paper presents a novel QoE provisioning system with micropayment for Voice of Internet Protocol (VoIP) and video streaming services (QmV2). QmV2leverages Software Defined Networking (SDN) to provide guaranteed QoE and the distributed ledger IOTA technology micropayment. More specifically, QmV2's SDN controller has an innovative QoE calculation mechanism utilizing Mean Opinion Score (MOS) that considers service flow monitoring parameters, including packet loss rate and delay. Upon a QoE request and receiving the IOTA payment, QmV2can provide the requested QoE for the service flow. We have implemented and evaluated QmV2using the POX SDN controller, the network emulator Mininet-WiFi with VoIP and video streaming. The results confirm QmV2delivers satisfactory user experiences (i.e., aligned with the guaranteed MOS values) for VoIP and video streaming applications with the confirmed IOTA payment.
Facial recognition technology and recommendation systems are the main technologies in the construction of intelligent libraries, but both technologies face privacy breaches and credibility issues. Blockchain, as an emerging technology, is having significant impact in many fields. This article delves into the role and core application value of blockchain technology in the construction of smart libraries in universities, and proposes smart library service architecture based on blockchain technology. This architecture provides a value-added path for smart library services, including secure storage, resource sharing, and optimizing book borrowing and returning systems. It can improve the quality of resource services and meet the increasing service needs of readers. The effectiveness and practicality of this method have been verified through experiments.
In this paper, we present the first bare metal comparison of modern blockchains, including Algorand, Avalanche, Diem, Ethereum, Quorum and Solana. This evaluation was conducted with the recent Diablo benchmark suite, a framework to evaluate the performance of different blockchains on the same ground. By tuning network delays in our controlled environment we were able to reproduce performance trends obtained in geo-distributed settings, hence demonstrating the relevance of bare metal evaluations to better understand blockchain performance.
Pramitha Fernando, An Braeken, Madhusanka Liyanage
The Internet of Things (IoT) is rapidly spreading across a wide range of applications because it is a critical technology for overcoming interoperability and heterogeneity barriers in many applications. IoT is increasingly being deployed in a distributed setting because of the vast number of devices and the physical dispersal of many use cases. Because IoT devices are often resource-restricted, this scattered implementation style exposes devices to unprecedented privacy and security risks. Distributed Ledger Technologies (DLT), such as blockchain, appear to be a perfect solution to integrate with IoT systems to overcome these challenges thanks to its key pillars: decentralisation, transparency and immutability. The use of blockchain in IoT has been widely examined, and the findings demonstrate how blockchain can be a crucial enabler for IoT. However, blockchain consensus mechanisms are often very energy-intensive, whereas IoT devices are resource-constrained with limited computational power, storage and energy. Therefore, as the literature emphasises, new consensus algorithms could solve most of these issues associated with blockchain technology. Holochain is an emerging DLT that promises to provide blockchain's key benefits and eliminate problems that come with it, such as consensus algorithms and the requirement to maintain a globally synchronised ledger. It has already attained the research community's awareness due to its potential to replace blockchain as a distributed computing solution. This paper compares blockchain and holochain in the context of IoT, considering scalability, availability, security and resource requirements.
Flaviene Scheidt de Cristo, Wazen M. Shbair, Lucian Trestioreanu, Radu State
The XRP Ledger is one of the oldest and most well-established blockchains, using a particular type of consensus mechanism that differs from the typical Proof of Work and Proof of Stake. The underlying p2p network uses flooding to dis-seminate certain types of messages during the consensus rounds, leading to performance and scalability issues. In this work, we propose the use of publisher/subscriber dissemination on the XRPL using GossipSub to diminish the message overhead. We use Flexi-pipe, a tool that allows integration between the XRPL validator and GossipSub, to evaluate the improvements brought.