Andrew Meegan, Shaen Corbet, Charles Larkin, Brian M. Lucey
Blockchain technology appears to be ready to revolutionise a broad number of industries. However, the blockchain itself contains a number of inefficiencies and areas for improvement, namely: transaction fees and transaction speeds. Directed acyclic graphs (DAGs) address, and improve on these inefficiencies and a number of digital currencies utilising this technology have already begun to appear. This paper provides an explanation of the technology behind DAG-based assets, while identifying and highlighting strategic advantages that DAGs possess over traditional blockchains. We conduct an EGARCH volatility analysis of a range of blockchain-based and DAG-based cryptocurrencies in the aftermath of a range of market shocks, taking the form of regulatory announcements such as bans and broad restrictions for cryptocurrencies. We find that DAG-based assets become increasingly responsive to market shocks as they mature. Such behaviour mirrors that of established cryptocurrencies such as Bitcoin, Ethereum and Litecoin, providing evidence that DAG-based cryptocurrencies now share similar characteristics to traditional blockchain-chain based products.
Farocki. Together with his sister, Anna Groos, Jan directed and produced multiple film projects (including www.endzeit.at). The joy of 1 The Etherum project is a public, global, open-source, blockchain-based distributed computing platform for 'decentralised' applications. First proposed in December 2013 by Vitalik Buterin, it went 'live' in July 2015. Like other blockchains, it has its own cryptocurrency (in this case, 'Ether' or in short ETH) as inherent part of its protocol design. Cf ethereum.org/ what-is-ethereum/ 2 These points will be taken up directly, but see: CleanApp (2018) 'The Wood-Zamfir Governance Debates,' blogger, Crypto Law Review,
Syada Tasmia Alvi, Mohammed Nasir Uddin, Linta Islam, Sajib Ahamed
Voting seem to be a very significant sign of political action, but it is very pathetic that a substantial majority of the world `s population do not have confidence in their voting system. There are different drawbacks and problems for a very long time in the conventional voting system. Several countries prefer to use a centralized voting process that may cause certain inconsistencies. The security and transparency issue is a challenge to the traditional structure from worldwide elections. One of the solutions to all of these challenges is Blockchain technology. New ideas are being provided to create new forms of digital services. Since it strains a decentralized structure and multiple people own the whole database system. Blockchain will reduce the deception of database abuse by implementing blockchain in a voting framework. In order to ensure a safe voting system, we have proposed a blockchain-based distributed infrastructure that offers fairness, transparency and flexibility over the current system. To assess our protocol, we have implemented it on Ethereum and done performance analysis based on security properties and gas cost.
Blockchain is a technology for storing an immutable history of transactions in a decentralized platform by using cryptographic principles. Many industries have become interested in adopting blockchain within their IT systems. However, the accessibility, privacy, performance, and scalability aspects of different blockchain-based platforms are still legitimate concerns when designing an enterprise solution. Permissioned blockchain frameworks facilitate a way to immutably store confidential records. Numerous research studies have been carried out on the opportunities, challenges, application areas, and performance analysis of different public and permissioned blockchain-based platforms. However, the implication of blockchain in recent private enterprise solution requires detailed comparative analysis. This paper conducts a performance and scalability analysis of popular private blockchain platforms, including Ethereum (private deployment), Quorum, Corda, and Hyperledger Fabric. Each of these platforms is assessed by varying the workloads (no. of transactions and nodes) and determining the performance evaluation metrics such as throughput and network latency.
The blockchain technology is quickly becoming the most disruptive technology of recent times. This technology has generated a lot of buzz and optimism, and it has gained a lot of attention from both the public and private sectors. Information can be transferred using blockchain technology in a manner that is confidential, safe, reliable, and open to scrutiny. This analysis focuses on the ways in which blockchain technology can be used to solve problems related to scalability and give solutions in the context of the healthcare industry. In light of this, the proposed solutions can be categorized into two primary categories: storage optimization and blockchain redesign. However, there are still several restrictions, such as the block size, the enormous volume of data and transactions, the number of nodes, and the obstacles posed by the protocol. It has seen widespread application in decentralized crypto currencies like Bitcoin and Ethereum, for example. An example of a public blockchain application that was successful, Bitcoin, was the impetus for a significant increase in research and development into blockchain technology. Nevertheless, scalability continues to be a significant obstacle. According to the facts that we've compiled, the primary causes of scalability issues appear to be bottlenecks in the transaction throughput, the network latency, and the consensus methods. On the other side, the potential for scalability includes the application of techniques like as sharding, hybrid systems, and off-chain computations. We also examine the consequences of these findings as well as prospective paths for future study to help solve the scalability problems that blockchain-based systems provide.
Access control in Internet of Things (IoT) systems has long been facing with single-point-of-failure, collusion and other security issues. Deploying most of the access control procedures on blockchain makes it more trustworthy. However, the miscellaneous transaction data on the public blockchain incurs an extra burden on computing and communication overhead, which hinders its application for IoT devices. Additionally, the demands of rapid response in industrial IoT scenarios (e.g., edge computing scenarios) is hardly realized under a public blockchain. In this brief, we propose an IoT-applicable access control model under an original double-layer blockchain architecture, in which the mortgage/registration and control processes can be disaggregated. Depending on this architecture, the communication overhead for IoT devices is reduced and a rapid response is achieved. With linear secret sharing scheme, attribute-based access policies for resource objects are established to ensure fine-grained access control. We further implement a smart contract prototype on Ethereum and Fisco Bcos. Extensive experiments and numerical analysis demonstrate the feasibility of our proposed model.
The interconnection of private resources on public infrastructure, user mobility and the emergence of new technologies (vehicular networks, sensor networks, Internet of things, etc.) have added new requirements in terms of security on the server side as well as the client side. Examples include the processing time, mutual authentication, client participation in the choice of security settings and protection against traffic analysis. Internet of Things (IoT) is in widespread use and its applications cover many aspects of today's life, which results in a huge and continuously increasing number of objects distributed everywhere.Security is no doubt the element that will improve and strengthen the acceptability of IoT, especially that this large scale deployment of IoT systems will attract the appetite of the attackers. The current cyber-attacks that are operational on traditional networks will be projected towards the Internet of Things. Security is so critical in this context given the underlying stakes; in particular, authentication has a critical importance given the impact of the presence of malicious node within the IoT systems and the harm they can cause to the overall system. The research works in this thesis aim to advance the literature on IoT authentication by proposing three authentication schemes that satisfy the needs of IoT systems in terms of security and performance, while taking into consideration the practical deployment-related concerns. One-Time Password (OTP) is an authentication scheme that represents a promising solution for IoT and smart cities environments. This research work extends the OTP principle and propose a new approach to generate OTP based on Elliptic Curve Cryptography (ECC) and Isogeny to guarantee the security of such protocol. The performance results obtained demonstrate the efficiency and effectiveness of our approach in terms of security and performance.We also rely on blockchains in order to propose two authentication solutions: first, a simple and lightweight blockchain-based authentication scheme for IoT systems based on Ethereum, and second, an adaptive blockchain-based authentication and authorization approach for IoT use cases. We provided a real implementation of our proposed solutions. The extensive evaluation provided, clearly shows the ability of our schemes to meet the different security requirements with a lightweight cost in terms of performance.
Pooled mining is the de facto mining pattern in public, PoW (Proof of Work) based blockchain systems like Bitcoin and Ethereum. Mining pool aggregates discrete miners’ computation power to improve probability of getting the right block, and stabilize miners’ rewards. Miners reach consensus among pools, and maintain the whole blockchain network's stability. Due to architecture constrains across underlying transmission mechanism, computation power differences among nodes, and consensus algorithms, mining pools are facing increasing performance challenges, which lead to wastes of computing resources and loss of miners’ rewards. Based on analysis of mining pool architecture, this paper proposed a numerical model MENM (Miner Efficiency Numerical Model) to measure miner's computing efficiency, and a performance tuning mechanism DDCT (Dynamic Difficulty Calculation and Tuning) to dynamically adjust individual miner's difficulty in a pool based on MENM value, to improve mining pool's efficiency. The proposed tuning mechanism is also tested against a small experimental PoW mining pool to validate its effect.
Swarm Robotics can be used in many applications. But they suffer from certain limitations that make them undesirable in Surveillance applications. Among their limitations is the absence of scalability and security. Currently, these robots do not have framework that allows it to communicate with each other to execute missions autonomously and transparently. Blockchain is the new technology for distributed autonomous systems by providing set of computer nodes for data storage and distribution among the nodes in the system. Each participating node can protect and validate the data in the blockchain system. No modifications can be performed on the data records due to the fact that it is been watched by all the users. Based on the blockchain features, we focus on this research how blockchain applications can make swarm robots securely connected using Ethereum smart contracts. Starting with surveillance missions deployment task, we propose a decentralized application (DApp) for that. Then, blockchain is used by the swarms to establish the Ethereum private networks that allows them to communicate and carry out tasks. We set a test swarm robotics system and evaluate the blockchain for its performance, scalability, recoverability, and responsiveness. In conclusion, we found that blockchain enables a swarm to be globally securely connected, but there are still need for performance enhancement.
P. Saengduean, Sutthipong Noisagool, Farida Chamchod
In this study, we investigate financial crashes in the cryptocurrency market including both mini and major crashes for two cryptocurrencies, Bitcoin and Ethereum, during the period that the digital market crashed in 2018. By applying techniques in topological data analysis, we are able to predict financial transitions and explore optimal values of the window size and the dimension of point cloud data to obtain good early warning signals. Our results demonstrate good early warning signals before the financial crashes and also show that the L1-norm and C1– norm of persistent landscapes peak before the crashes occur.
Background: As public health strategists and policymakers explore different approaches to lessen the devastating effects of novel coronavirus disease (COVID-19), blockchain technology has emerged as a resource that can be utilized in numerous ways. Many blockchain technologies have been proposed or implemented during the COVID-19 pandemic; however, to the best of our knowledge, no comprehensive reviews have been conducted to uncover and summarise the main feature of these technologies. Objective: This study aims to explore proposed or implemented blockchain technologies used to mitigate the COVID-19 challenges as reported in the literature. Methods: We conducted a scoping review in line with guidelines of PRISMA Extension for Scoping Reviews (PRISMA-ScR). To identify relevant studies, we searched 11 bibliographic databases (e.g., EMBASE and MEDLINE) and conducted backward and forward reference list checking of the included studies and relevant reviews. The study selection and data extraction were conducted by 2 reviewers independently. Data extracted from the included studies was narratively summarised and described. Results: 19 of 225 retrieved studies met eligibility criteria in this review. The included studies reported 10 used cases of blockchain to mitigate COVID-19 challenges; the most prominent use cases were contact tracing and immunity passports. While the blockchain technology was developed in 10 studies, its use was proposed in the remaining 9 studies. The public blockchain technology was the most commonly utilized type in the included studies. All together, 8 different consensus mechanisms were used in the included studies. Out of 10 studies that identified the used platform, 9 studies used Ethereum to run the blockchain. Solidity was the most prominent programming language used in developing blockchain technology in the included studies. The transaction cost was reported in only 4 of the included studies and varied between USD 10−10 and USD 5. The expected latency and expected scalability were not identified in the included studies. Conclusion: Blockchain technologies are expected to play an integral role in the fight against the COVID-19 pandemic. Many possible applications of blockchain were found in this review; however, most of them are not mature enough to reveal their expected impact in the fight against COVID-19. We encourage governments, health authorities, and policymakers to consider all blockchain applications suggested in the current review to combat COVID-19 challenges. There is a pressing need to empirically examine how effective blockchain technologies are in mitigating COVID-19 challenges. Further studies are required to assess the performance of blockchain technologies’ fight against COVID-19 in terms of transaction cost, scalability, and/or latency when using different consensus algorithms, platforms, and access types.
Inspired by the recent boom in decentralized finance (DeFi) and the unprecedented success of flash loan projects in this ecosystem, we introduce a decentralized debt derivative named atomic bonded cross-chain debt (ABCD) to bridge the gap between the growth of lending protocols on Ethereum and other UTXO-based blockchains specifically Bitcoin. We think of ABCD as the alphabet of interoperability for DeFi and as a credit infrastructure which unlike the current protocols is not limited by requiring either smart contracts, over-collateralization, or instantaneous payback.
We propose a new type of variable coverage method called Dynamic Array Double-Access Attack (DADA Attack) in Ethereum Virtual Machine (EVM). Such attack can read and write operations anywhere in the storage area, resulting in abnormal execution of contract and out of control. Vulnerable contracts with such attacks will directly lead to the loss of a large amount of property. To evaluate the effectiveness of such Double-Access Attack, we conducted theoretical analysis and experimental verification, finding attack success rate is 100% under the condition that dynamic array length is controllable.
Blockchain is starting to be deployed in industries by enabling Internet of Things (IoT) for autonomous deviceto-device transactions through distributed blockchain-based immutable ledger technology. However, traditional block-based blockchain techniques, such as Bitcoin and Ethereum, are not suitable for IoT transactions due to its low throughput, high computation overhead, and costly transaction fee. To satisfy the requirements of IoT, DAG-based approaches, aiming to provide cheap blockchain services with low latency and high throughput, are emerging. In this paper, we present a set of comprehensive experimental studies on IOTA, a representative DAG-based blockchain, and aim to exhibit its unique characteristics mainly from two aspects: performance and security. We have developed a series of benchmark tools and judiciously selected typical configurations to perform experimental examinations with a real private IOTA network. Our studies reveal several interesting findings: 1) The throughput of IOTA is higher than the traditional block-based blockchain, but far less than the reported thousands TPS in its whitepaper, even with scaling-up configurations; 2) The database query heavily impacts the performance of IOTA, even more than its PoW (Proof of Work) process. We make our benchmark tools in public and expect our works can inspire system architects, application designers, and practitioners with new optimization directions and potential application cases for further exploration.
The scarcity and exigency for blood and organs has created many discrepancies in current approaches. These have created the criteria for malpractices such as organ trafficking and black market selling. This research presents a solution with a secured-smart blood and organ donation web developed system, allowing both patients and healthcare providers to access information about the blood and organ processing records. The database would be managed using the Blockchain technology which could be only accessed by authorized users. Finally, tracking all registered donors, the proposed system generates a smart identity developed by Ethereum Smart Contract (ESC). System predicts blood demand for the future ten years using Linear Regression Model with 0.998 of high R-squared accuracy value. This reduces shortages and wastage of blood. Also, using global positioning system and K-Nearest Neighbors Machine Learning algorithm, the system finds the best matches among donors and seekers according to the nearest location. Further, the system will automatically send questionnaires for registered users to identify and evaluate their awareness and issues about organ donation. Overall, this study aims for a secured and transparent web application. Thus, it facilitates an innovative and a productive blood donation and organ transplantation process in Sri Lankan healthcare sector.
Ahsan Manzoor, An Braeken, Salil S. Kanhere, Mika Ylianttila · 5 authors
Data is central to the Internet of Things (IoT) ecosystem. With billions of devices connected, most of the current IoT systems are using centralized cloud-based data sharing systems, which will be difficult to scale up to meet the demands of future IoT systems. The involvement of such a third-party service provider requires also trust from both the sensor owner and sensor data user. Moreover, fees need to be paid for their services. To tackle both the scalability and trust issues and to automatize the payments, this paper presents a blockchain-based marketplace for sharing of the IoT data. We also use a proxy re-encryption scheme for transferring the data securely and anonymously, from data producer to the consumer. The system stores the IoT data in cloud storage after encryption. To share the collected IoT data, the system establishes runtime dynamic smart contracts between the sensor and data consumer without the involvement of a trusted third-party. It also uses a very efficient proxy re-encryption scheme which allows that the data is only visible by the owner and the person present in the smart contract. This novel combination of smart contracts with proxy re-encryption provides an efficient, fast and secure platform for storing, trading and managing sensor data. The proposed system is implemented using off-the-shelf IoT sensors and computer devices. We also analyze the performance of our hybrid system by using the permission-less Ethereum blockchain and compare it to the IBM Hyperledger Fabric, a permissioned blockchain.
Smart contract (SC) is an extension of BlockChain technology. Ethereum BlockChain was the first to incorporate SC and thus started a new era of crypto-currencies and electronic transactions. Solidity helps to program the SCs. Still, soon after Solidity's emergence in 2014, Solidity-based SCs suffered many attacks that deprived the SC account holders of their precious funds. The main reason for these attacks was the presence of vulnerabilities in SC. This paper discusses SC vulnerabilities and classifies them according to the domain knowledge of the faulty operations. This classification is a source of reminding developers and software engineers that for SC's safety, each SC requires proper testing with effective tools to catch those classes' vulnerabilities.
Mwrwan Abubakar, Zakwan Jaroucheh, Ahmed Al‐Dubai, Bill Buchanan
The original consensus algorithm - Proof of Work (PoW) has been widely utilized in the blockchain systems and is been adopted by many cryptocurrencies, such as Bitcoin and Ethereum, among many others. Nevertheless, the concept has received criticisms over its high energy consumption. This is induced by the necessity for all nodes in the network to communicate synchronously for consensus over the ledger state to be reached. Additionally, the concept has also shown clear limitations regarding performance and throughput. In trying to rectify this issue, the paper proposes the introduction of a new hybrid consensus protocol known as the Proof of Notarized Work (PoNW). The PoNW concept reduces the number of nodes that need to achieve consensus, thereby reducing the overall energy consumption in the current PoW. In addition, we propose using a decentralized random beacon to select nodes to participate in the mining process randomly. Therefore, our algorithm promises to achieve higher scalability and consistency levels without conceding its decentralization. When this is paired with a Byzantine Fault Tolerance (PBFT) verification, the system gains the ability to replace the probabilistic finality in current PoW with absolute finality in a matter of seconds, solving the issue of scalability. Finally, the study will look into the proposed algorithm's security and provides threats model to insure an acceptable failure probability. Results from the security analysis have shown that our consensus algorithm ensures forks cannot occur, and it remains secure and consistent even amid numerous attacks.
Blockchain is a promising new technology, generating widespread interest, and receiving considerable attention in the research community, such as academia and industry. This interest started with the success of Bitcoin but took speed with the promise of smart contracts and a vast number of applications. While there is a broad interest in developing blockchain systems for specific use cases, there is a lack of tools to perform their evaluation and implementation decisions may hamper fast progress. This report provides the review of security and performance of public and private blockchain framework, where each of which is represented by the two well-known papers, the first is titled “On the Security and Performance of Proof of Work Blockchains” and the second paper is titled “BLOCKBENCH: A Framework for Analyzing Private Blockchains”. The first paper introduces a novel quantitative framework to analyze the security and performance implications of various consensus and network parameters of PoW blockchains. The framework allows for capture existing PoW-based deployments as well as PoW blockchain variants that are instantiated with different parameters, and to objectively compare the tradeoffs between their performance and security provisions. In the second paper, the authors describe BlockBench, the first evaluation framework for analyzing private blockchains. BlockBench measures overall and componentwise performance in terms of throughput, latency, scalability, and fault-tolerance. Next, BlockBench is used to conduct a comprehensive evaluation of three major private blockchains: Ethereum, Parity, and Hyperledger Fabric. Furthermore, there are gaps in performance among the three systems which are attributed to the design choices at different layers of the blockchain’s software stack.
Blockchain as a distributed system that confirms security and reliability have started a new era of a solid and consensus system.Blockchains focus on cryptocurrency is encouraging many other processes to follow the same reliable approach of security.Almost all procedures and operations are now invited to be electronically performed in the digital Ethereum network that has been presented. Moreover, this study proposed the use of an Ethereum network on a blockchain platform in the study when it was moved to a blockchain network to confirm transparency.An E-voting system sample has been tested by using an Ethereum network smart contracts inwhich solidity language and wallets were used. In the voting test, the Ethereum blockchain will be able to collect records in which voters can use their Ethereum wallets or android devices to submit their votes in a consensus node.The researchers studied the voting system taking Jordan as a case study.This study recommended the adaptation of e-voting to support transparency and voters trust to reduce corruption and unreliability in the voting processes. Moreover, the use of this system will allow a voter to vote from home in the time of the pandemic.\n\n
Jun-Mo Lee, Seong‐Jun Kim, Sang-Hyeon Park, Soo‐Mook Moon
Cryptocurrencies such as Bitcoin and Ethereum have made payment transactions possible without a trusted third party, but they have a scalability issue due to their consensus mechanisms. Payment networks have emerged to overcome this limitation by executing transactions outside of the blockchain, which is why these are referred to as off-chain transactions. In order to establish a payment channel between two users, the users lock their deposits in the blockchain, and then they can pay each other through the channel. Furthermore, payment networks support multi-hop payments that allow users to transfer their balances to other users who are connected to them via multiple channels. However, multi-hop payments are hard to be accomplished, as they are heavily dependent on routing users on a payment path from a sender to a receiver. Although routing hubs can make multi-hop payments more practical and efficient, they need a lot of collateral locked for a long period and have privacy issues in terms of payment history. We propose RouTEE, a secure payment routing hub that is fully feasible without the hub's deposit. Unlike existing payment networks, RouTEE provides high balance liquidity, and details about payments are concealed from hosts by leveraging trusted execution environments (TEEs). RouTEE is designed to make rational hosts behave honestly, by introducing a new routing fee scheme and a secure settlement method. Moreover, users do not need to monitor the blockchain in real-time or run full nodes. They can participate in RouTEE by simply verifying block headers through light clients; furthermore, having only one channel with RouTEE is sufficient to interact with other users. Our implementation demonstrates that RouTEE is highly efficient and outperforms Lightning Network that is the state-of-the-art payment network.
José Eduardo de Azevedo Sousa, Vinícius Cunha Oliveira, Júlia Almeida Valadares, Alex Borges Vieira · 7 authors
O crescimento do interesse em Ethereum leva a preocupações relacionadas à sua segurança, dado que já houveram ataques que exploraram o seu mecanismo de tarifação ou Penny Attack. Esses ataques afetaram a rede ocasionando lentidão nas transações e há indícios que Ethereum continua susceptível a esse tipo de ataque. Analisamos o comportamento da rede Ethereum durante um Penny Attack, buscando técnicas de aprendizado de máquina para detectá-lo previamente, utilizando atributos das transações. Nossas técnicas tiveram AUC, Fb e recall superior a 94%, 82% e 98% respectivamente.