In early 2020, World Health Organization (WHO) declared that the world is facing the COVID-19 pandemic. This pandemic is caused by the emergence of a new type of coronavirus which spreads very quickly. Because of this pandemic, the government has issued health protocols that use a lot of COVID-19 tests. However, cases of forgery of test certificates often occur in paper-based test certificate. To overcome this problem, we propose a COVID-19 test certificate management system using blockchain technology. By using blockchain technology, the system can be used by multiple entities, even though the entities that use it do not have trust relationship beforehand. This is possible because blockchain is a technology that uses a decentralized network that can store its data with a secure consensus mechanism. The system built using the Ethereum platform, which is a public non-permissioned blockchain that supports decentralized application development through smart contracts that executed via EVM (Ethereum Virtual Machine). The system has been developed using 3-layers architecture, which contains network, software, and application layer. The evaluation shows that the system successfully fulfills the COVID-19 test certificate management requirement. The system can be used for tester registration, and create, revoke, display certificates. Furthermore, by using encryption and digital signature mechanism, the system can protect patient privacy and data integrity. The system has also succeeded in fulfilling the availability and security requirements. However, due to the nature of Ethereum consensus mechanism, the system has much lower response time, compared to the centralized counterpart.
BACKGROUND: In clinical genomics, sharing of rare genetic disease information between genetic databases and laboratories is essential to determine the pathogenic significance of variants to enable the diagnosis of rare genetic diseases. Significant concerns regarding data governance and security have reduced this sharing in practice. Blockchain could provide a secure method for sharing genomic data between involved parties and thus help overcome some of these issues. OBJECTIVE: This study aims to contribute to the growing knowledge of the potential role of blockchain technology in supporting the sharing of clinical genomic data by describing blockchain-based dynamic consent architecture to support clinical genomic data sharing and provide a proof-of-concept implementation, called ConsentChain, for the architecture to explore its performance. METHODS: The ConsentChain requirements were captured from a patient forum to identify security and consent concerns. The ConsentChain was developed on the Ethereum platform, in which smart contracts were used to model the actions of patients, who may provide or withdraw consent to share their data; the data creator, who collects and stores patient data; and the data requester, who needs to query and access the patient data. A detailed analysis was undertaken of the ConsentChain performance as a function of the number of transactions processed by the system. RESULTS: We describe ConsentChain, a blockchain-based system that provides a web portal interface to support clinical genomic sharing. ConsentChain allows patients to grant or withdraw data requester access and allows data requesters to query and submit access to data stored in a secure off-chain database. We also developed an ontology model to represent patient consent elements into machine-readable codes to automate the consent and data access processes. CONCLUSIONS: Blockchains and smart contracts can provide an efficient and scalable mechanism to support dynamic consent functionality and address some of the barriers that inhibit genomic data sharing. However, they are not a complete answer, and a number of issues still need to be addressed before such systems can be deployed in practice, particularly in relation to verifying user credentials.
Peng Wang, Ning Xu, Haibin Zhang, Wen Sun · 5 authors
The Internet of Things (IoT), while providing comprehensive interconnection and ubiquitous services, poses security issues by enabling resources sharing among various devices from different untrusted authorities. Blockchain, as a distributed ledger, provides a traceable and verifiable platform to ensure the secure access control in IoT. The existing works based on blockchain may bring up intolerable computing overhead and delay to the lightweight IoT devices. In this article, we propose a dynamic and lightweight attribute-based access control framework for blockchain-empowered IoT, to achieve secure and fine-grained authorization. The proposed scheme allows access to resources by evaluating attributes, operations, and the environment relevant to a request. The access policy is executed through smart contract in blockchain for security and flexibility. To further adapt to IoT device constraints, we design a access control framework based on decentralized application (DApp), which can maintain tamper proof in a timely manner and be adapt to the delay-intolerant application. When delay-intolerant access is required, access can be allowed according to local replica of the blockchain, without a consensus of blockchain network. Considering the time-varying attributes of IoT devices, a trust management scheme is proposed based on the Markov chain to resist the security fluctuation caused by the vulnerability of IoT devices. In the experiments, we deploy our system prototype on Ethereum to evaluate the feasibility and effectiveness of the scheme. The results show the proposed scheme can achieve secure, high throughput, and flexible access control in IoT.
Freelancing marketplace is a site or platform that connects two parties in processing service transactions at an hourly rate or per project. A conventional freelancing marketplace is a place for freelancers to find work and transact digitally. This study aims to propose a prototype of a freelancing marketplace system that is distributed and decentralized, secure, and transparent using smart contract-based blockchain technology. The method used in this study is a prototype which is a fast method of developing a software system. The developed prototype is a system that is based on the Ethereum public blockchain network, utilizes a smart contract mechanism in its transaction activities, and use IPFS in the storage and sharing of documents on it. According to the findings of the research, transaction data input in the freelancing marketplace system prototype environment can be executed by smart contracts and saved on the blockchain network, indicating that the transaction data will be stored more securely, tamper proof, and transparent.
Atif Naseer, Enrique Nava Baro, Sultan Daud Khan, Y. Vila · 5 authors
In recent years, cryptocurrency has become gradually more significant in economic regions worldwide. In cryptocurrencies, records are stored using a cryptographic algorithm. The main aim of this research was to develop an optimal solution for predicting the price of cryptocurrencies based on user opinions from social media. Twitter is used as a marketing tool for cryptoanalysis owing to the unrestricted conversations on cryptocurrencies that take place on social media channels. Therefore, this work focuses on extracting Tweets and gathering data from different sources to classify them into positive, negative, and neutral categories, and further examining the correlations between cryptocurrency movements and Tweet sentiments. This paper proposes an optimized method using a deep learning algorithm and convolution neural network for cryptocurrency prediction; this method is used to predict the prices of four cryptocurrencies, namely, Litecoin, Monero, Bitcoin, and Ethereum. The results of analyses demonstrate that the proposed method forecasts prices with a high accuracy of about 98.75%. The method is validated by comparison with existing methods using visualization tools.
Muhammad Milhan Afzal Khan, Hafiz Muhammad Azeem Sarwar, Muhammad Awais
Abstract In Ethereum blockchain, whenever a transaction of smart contract is executed, transaction fee is charged in terms of Ethers. To calculate the transaction fee, a computational unit, gas is introduced in smart contracts. Gas consumption is calculated against the smart contract source code execution. The transaction initiator sets the gas price against per unit of gas and the total gas limit. If the gas limit is sufficient, the transaction will be mined otherwise it will be reverted. Smart contracts of Ethereum can be written in any high‐level language such as Solidity, Vyper, Python, Java and so forth, but Solidity is massively used for smart contracts creation. In this article, we have examined the 5000 transactions of Solidity based smart contracts from Etherscan and performed statistical analysis on opcodes and source code parameters used in these transactions to identify gas costly patterns. Our statistical results (correlation and regression) analyze the relationship of Solidity parameters and opcodes with the gas consumption. Factors causing an increase or decrease in the gas consumption of smart contracts are highlighted in this article. The regression analysis showed that 87.8% of the variability in the response variable (gas consumption) is due to the parameters used in this analysis. Our results will help the smart contract developers to write the gas optimized smart contracts. The results can be beneficial for end users as they will have to pay gas price for less number of gas units.
Blockchain is a decentralized technology. When it comes to resolving business issues, it wields considerable power. Every transaction on the blockchain is encrypted, and each transaction is linked to a previous transaction or record. Blockchain transactions are validated by algorithms running on nodes. A single entity cannot start a transaction. Eventually, blockchain provides transparency by allowing any participant to view transactions at any moment. Smart contracts provide secure transactions, minimizing the risk of third-party interruptions. Ethereum is a decentralized platform based on smart contracts. It enables developers to create markets that transfer money according to the instructions given years ago. Blockchain is distinguished by two key characteristics: immutability and decentralization. Deals are completed faster; Transactions and authentication are completed in a matter of seconds, and much more.
The charity management system is a vital information management system. the information must be entirely open for society, and anyone has the right to supervise. Therefore, we use the characteristics of the blockchain to be tamper-proof, decentralized, autonomous, observable, verifiable, and information-sharing to develop a secure and robust charity information management system. Use the ring signature mechanism to protect the privacy of supervisors. A charity contract system was developed based on the Ethereum experimental environment, code the traditional charity text contract, storage and execution of contracts both are on the blockchain, which ensures the autonomy and reliability of the charity project and the trustworthiness and credibility. Our system is a novel innovation that can succeed the traditional public platform for charity.
The growth of cryptocurrencies has attracted much attention from a variety of fields, especially in academic research. Their protocol is built and developed on blockchain technology. One of them is Ethereum which is a popular and highest valued cryptocurrency on the market. Therefore, the need for space to store transactions information increases, leading to the creating of blocks is extremely urgent. This work is called Ethereum mining. Miners have to solve a problem called Ethash (Ethereum’s Proof-of-Work) to find the results satisfied the requirements of the problem. In this paper, we proposed a hardware design architecture to perform the Ethash mining system. To obtain the high performance for the Ethashed block mining system, the fast design of the Keccak function is also proposed. The design is implemented on Xilinx Virtex 7 FPGA-VC707. The throughput of our proposed Keccak function reaches 8 Gbps with efficiency of 5.5 Mbps/Slice. The hashrate of the mining system reaches 88KH/s at frequency of 19.231MHz.
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
The machine learning method has been used in stock price prediction for a long time, and the price of cryptocurrencies such as bitcoin has attracted more and more attention in recent years. This paper aims to improve the method applicable to the stock market and try to use it in cryptocurrency price prediction. A simple three-layered feedforward artificial neural networks (ANN) model was applied in this paper to predict the daily directions of cryptocurrency prices. The historical trading data of Bitcoin, Ethereum, and Cardano were used in the experiments. Nine selected technical indicators were preprocessed into discrete trend data, and they were input into the model together with three additional indicators for training. This study has preliminarily obtained an effective result with price prediction accuracy of the three cryptocurrencies between 61% and 65%.
Lin Jin, Shuai Hao, Yan Huang, Haining Wang · 5 authors
Domain Name System (DNS) is known to present privacy concerns. To this end, decentralized blockchains have been used to host DNS records, so that users can synchronize with the blockchain to maintain a local DNS database and resolve domain names locally. However, existing blockchain-based solutions either do not guarantee a domain name is controlled by its "true" owner; or have to resort to DNSSEC, a not yet widely adopted protocol, for verifying ownership. In this paper, we present DNSonChain, a new blockchain-based naming service compatible with DNS. It allows domain owners to claim their domain ownership on the blockchain where DNS records are hosted. The core function of DNSonChain is to validate the domain ownership in a decentralized manner. We propose a majority vote mechanism that randomly selects multiple participants (i.e., voters) in the system to vote for the authority of domain ownership. To provide resistance to attacks from fraudulent voters, DNSonChain requires two rounds of voting processes. Our security analysis shows that DNSonChain is robust against several types of security failures, able to recover from various attacks. We implemented a prototype of DNSonChain as an Ethereum decentralized application and evaluate it on an Ethereum Testnet.
As the largest blockchain platform supporting smart contracts,millions of smart contracts have been deployed on Ethereum.Since the deployed smart contracts cannot be modified even if the contracts contain bugs,it is critical for developers to eliminate bugs prior to the deployment.Many smart contract analysis tools have been proposed.These tools either use bytecode-based symbolic execution to detect bugs,or convert the source code to an intermediate representation and then detect bugs.The tools based on symbolic execution usually cannot cover many types of bugs in source code.Converting the source code to an intermediate representation negatively impacts the detection speed.Moreover,these tools are bug detectors,which cannot automatically fix bugs based on analysis results.To address these limitations,we propose an approach named SolidityCheck,which employs regular expressions,program instrumentation and statement replacement in source code to quickly detect bugs and fix certain types of bugs.We conduct extensive experiments to evaluate SolidityCheck.The experimental results show that,compared with existing approaches,SolidityCheck demonstrates excellent performances on multiple indicators.
Profound changes driven by decarbonization, decentralization, and digitalization are disrupting the energy industry, bringing new challenges to its key stakeholders. In the attempt to address the climate change issue, increasing penetration of renewables and mobility electrification augment the complexity of the electric grid, thus calling for new management approaches to govern energy exchanges while ensuring reliable and secure operations. The emerging blockchain technology is regarded as one of the most promising solutions to respond to the matter in a decentralized, efficient, fast, and secure way. In this work, we propose an Ethereum-based charging management framework for electric vehicles (EVs), tightly interlinked with physical and software infrastructure and implemented in a real-world demonstration site. With a specifically designed solidity-based smart contract governing the charging process, the proposed framework enables secure and reliable accounting of energy exchanges in a network of trustless peers, thus facilitating the EVs’ deployment and encouraging the adoption of blockchain technology for everyday tasks such as EV charging through private and semi-private charging infrastructure. The results of a multi-actor implementation case study in Switzerland demonstrate the feasibility of the proposed blockchain framework and highlight its potential to reduce costs in a typical EV charging business model. Moreover, the study shows that the suggested framework can speed up the charging and billing processes for EV users, simplify the access to energy markets for charging station owners, and facilitate the interaction between the two through specifically designed mobile and web applications. The implementation presented in this paper can be used as a guideline for future blockchain applications for EV charging and other smart grid projects.
Siqi Zeng, Kosuke Kaneko, Yan Ke, Haowen Tan · 5 authors
This paper proposes a design of escrow scheme with blockchain technology. The purpose of this design is to solve the problem in overtaking service [1]. To achieve the objective, we take several simulations to evaluate the performance of our design. The paper will also introduce the reason why introducing the escrow scheme into blockchain technology. And the paper will briefly discuss the advantages and disadvantages of the design.
Energy storage provides an effective way of shifting temporal energy demands and supplies, which enables significant cost reduction under time-of-use energy pricing plans. Despite its promising benefits, the cost of present energy storage remains expensive, presenting a major obstacle to practical deployment. A more viable solution to improve the cost-effectiveness is by sharing energy storage, such as community sharing, cloud energy storage and peer-to-peer sharing. However, revealing private energy demand data to an external energy storage operator may compromise user privacy, and is susceptible to data misuses and breaches. In this paper, we explore a novel approach to support energy storage sharing with privacy protection, based on privacy-preserving blockchain and secure multi-party computation. We present an integrated solution to enable privacy-preserving energy storage sharing, such that energy storage service scheduling and cost-sharing can be attained without the knowledge of individual users' demands. It also supports auditing and verification by the grid operator via blockchain. Furthermore, our privacy-preserving solution can safeguard against a majority of dishonest users, who may collude in cheating, without requiring a trusted third-party. We implemented our solution as a smart contract on real-world Ethereum blockchain platform, and provided empirical evaluation in this paper 1 .
The era of Electric Vehicles (EVs) has influenced the very make and manufacture of vehicles resulting in low pollution and advanced battery life. On the other hand, the internet of things has also expanded allowing a number of devices to stay connected using the internet. Massive drawbacks faced by EVs today are the limitation in battery swapping and charging stations and limitation in the range of batteries used. This proposed paper aims to efficiently manage the best battery system apart from building the essential infrastructure. In some cases battery swapping option is also provided through other EV drivers or at registered stations. Hence a complete database of the EV network is required so that it is possible to swap and charge batteries successfully. An EV management using two blockchains as a data layer and network of the application is implemented in this work. The first step involves the development of a blockchain framework using Ethereum and the next step entails a direct acyclic graph. When integrated, these two methodologies prove to be an efficient platform that offers a viable solution for battery management in Electric Vehicles.
In this paper, we focus on the video streaming as a concrete application of the Peer-to-Peer (P2P) technology, and consider the problem of properly recording contributions made by each peer to make a fair differentiation of provided services. More specifically, we propose a simple implementation of distributed reward system for P2P video streaming by combining WebTorrent API and Ethereum-based smart contracts. We also conduct experiments to confirm that the prototype system certainly realizes a service differentiation.
Stefan Kitzler, Friedhelm Victor, Pietro Saggese, Bernhard Haslhofer
We present a measurement study on compositions of Decentralized Finance (DeFi) protocols, which aim to disrupt traditional finance and offer services on top of distributed ledgers, such as Ethereum. Understanding DeFi compositions is of great importance, as they may impact the development of ecosystem interoperability, are increasingly integrated with web technologies, and may introduce risks through complexity. Starting from a dataset of 23 labeled DeFi protocols and 10,663,881 associated Ethereum accounts, we study the interactions of protocols and associated smart contracts. From a network perspective, we find that decentralized exchange (DEX) and lending protocol account nodes have high degree and centrality values, that interactions among protocol nodes primarily occur in a strongly connected component, and that known community detection methods cannot disentangle DeFi protocols. Therefore, we propose an algorithm to decompose a protocol call into a nested set of building blocks that may be part of other DeFi protocols. This allows us to untangle and study protocol compositions. With a ground truth dataset that we have collected, we can demonstrate the algorithm’s capability by finding that swaps are the most frequently used building blocks. As building blocks can be nested, that is, contained in each other, we provide visualizations of composition trees for deeper inspections. We also present a broad picture of DeFi compositions by extracting and flattening the entire nested building block structure across multiple DeFi protocols. Finally, to demonstrate the practicality of our approach, we present a case study that is inspired by the recent collapse of the UST stablecoin in the Terra ecosystem. Under the hypothetical assumption that the stablecoin USD Tether would experience a similar fate, we study which building blocks — and, thereby, DeFi protocols — would be affected. Overall, our results and methods contribute to a better understanding of a new family of financial products.
When users deploy or invoke smart contracts on Ethereum, a fee is charged for avoiding resource abuse. Metered in gas, the fee is the product of the amount of gas used and the gas price. The more gas used indicates a higher transaction fee. In my doctoral research, we aim to investigate two widely studied issues regarding gas, i.e., gas estimation and gas optimization. The former is to predict gas costs for executing a transactions to avoid out-of-gas exceptions, and the latter is to modify existing contracts to save transaction fee. We target some problems that previous work did not solve: gas estimation for loop functions, and gas optimization for storage usage and arrays. We expect that my research can help Ethereum users avoid economical loss for out-of-gas exceptions and pay less transaction fee.
The frequent electricity transactions of multienergy complementary Energy Internet Cluster result in higher operating costs and increased risks of information security by traditional transaction mode. Therefore, based on the blockchain technology, this paper proposes an electricity trading architecture suitable for Community Energy Internet Cluster. Firstly, the article elaborates the basic structure of Energy Internet and blockchain, and analyzes the adaptability of blockchain applied to Energy Internet Cluster electricity transaction. Secondly, the process of establishing electricity trading platform and deploying smart contract based on Ethereum network is described in detail. Thirdly, the power transaction framework of Community Energy Internet Cluster is constructed, and the double auction mechanism is applied to complete matchmaking tradeoff, and the smart contract is designed. Finally, a practical energy trading platform is built through the Ganache client of Ethereum network. Case studies demonstrate the feasibility and effectiveness of the trading operation framework.
This paper investigates the relationship between the COVID-19 crisis and the two leading cryptocurrencies, Bitcoin and Ethereum, from 31 December 2019 to 18 August 2020. We also use an economic news sentiment index and financial market sentiment index to explore the possible mechanisms through which COVID-19 impacts cryptocurrency. We employ a VAR Granger Causality framework and Wavelet Coherence Analysis and find the cryptocurrency market was impacted in the early phase of the sample period through economic news and financial market sentiments, but this effect diminished after June 2020.
Ethereum, that enable development of decentralized applications, will likely to leverage cloud computing. In this research, we evaluate the performance of a cloud-based Ethereum network. We researched 3 Ethereum networks, namely: Ethereum mainnet, Ethereum testnet Ropsten, and Ethereum testnet Rinkeby. We analyze the computational resource utilization required to run an Ethereum node for a month as well as the costs involved. Research shows that the utilization of computing resources on the Main Net is generally higher than on the Test Net network. Computing resources used in the cloud cost thousands of dollars and this will increase as the number of nodes running to support the Ethereum network.
Long Zhang, Javier Ron, Benoît Baudry, Martin Monperrus
In this article, we present ChaosETH , a chaos engineering approach for resilience assessment of Ethereum blockchain clients. ChaosETH operates in the following manner: First, it monitors Ethereum clients to determine their normal behavior. Then, it injects system call invocation errors into one single Ethereum client at a time and observes the behavior resulting from perturbation. Finally, ChaosETH compares the behavior recorded before, during, and after perturbation to assess the impact of the injected system call invocation errors. The experiments are performed on the two most popular Ethereum client implementations: GoEthereum and Nethermind. We assess the impact of 22 different system call errors on those Ethereum clients with respect to 15 application-level metrics. Our results reveal a broad spectrum of resilience characteristics of Ethereum clients w.r.t. system call invocation errors, ranging from direct crashes to full resilience. The experiments clearly demonstrate the feasibility of applying chaos engineering principles to blockchain systems.
Jonathan Carrero, Ismael Rodrı́guez, Fernando Rubio
Auction security has been a major challenge for researchers in this area. For example, one of the biggest problems has always been the trust in a third party, an intermediary, which is the one who usually conducts the auction and knows the bids made by the participants. Over time, traditional methods have been overtaken by new technologies that eliminate the problems that arise when using traditional methods. Blockchain technology allows us to use its inherent characteristics of privacy, traceability and decentralization to conduct auctions with a much higher level of security and to execute auctions while reducing transaction costs. In addition, the automation of operations provided by smart contracts allows us to eliminate the intermediary, leading to additional cost savings. Furthermore, in contrast to previous technologies, the pseudo-anonymity of blockchain allows us to verify the authenticity of data, mitigating malicious behavior on the part of agents. In this paper we address this challenge; we present a smart contract that allows us to run an auction within the Ethereum blockchain at a relatively low cost, eliminating the intermediary and guaranteeing the trust of the agents involved in the auction. In particular, we concentrate on dealing with egalitarian social welfare, where the goal is to maximize the utility of the agent whose utility turns out to be minimal.