The article considers and investigates the system of decision making in the production processes of an agricultural enterprise. In dynamic conditions of decision-making and operational adjustments, a methodology of operational analysis of the current situation is needed to obtain the necessary results. Decentralized blockchain-based systems are the most promising for doing business. Usage areas of decentralized systems are production and logistics. Globalized production and distribution of agricultural tasks have brought a new milestone in the development and optimization of existing systems. The growing number of issues related to the optimization of internal processes in enterprises, has caused an urgent need for an effective solution to process tracking, which serves as an important tool for quality management and provides adequate protection of the process in the agricultural production chain. Blockchain is one of the main technologies that can provide innovative solutions for tracking agricultural products and food supply chains. Modern agricultural supply chains are a complex ecosystem that includes a number of stakeholders and therefore complicates the verification of important criteria: country of origin, stages of crop development, compliance with quality standards, yield monitoring. Ethereum Smart Contracts can effectively monitor and seamlessly integrate business operations and workflows for a stable supply of agricultural products. The agricultural sector has great potential for modernization and optimization of production, which in general can be a breakthrough for the economy as a whole. It is thanks to him that the country receives a significant flow of currency. After the abolition of tariffs restricting the supply of products to Europe, new markets were opened for production. Demand for agricultural products is high and by modernizing the management system, we will be able to get even better results. Also, the involvement of information technology provides good conditions for productive and confident development of small and medium-sized agricultural enterprises and farms. For example, blockchain technology will provide access to new markets and reduce the bureaucratic burden on the company, simplify communication with suppliers and customers.
Smart contracts offer a unique method of contracting that differs from the methods used for a long time in this regard; Because the agreement between the contracting parties appears in the form of a code that is run and executed by members of the Blockchain network or the nodes, without one of the parties being able to stop it; so that when a certain condition is met and the members of the network verify that, the related or the corresponding condition is executed automatically; therefore it's a contracting method that guarantees the process of contracts performance in the manner agreed upon, without the need to have a confidence in the other party or resort to a trusted body to verify the truth of that party or the object of contract; so we thought about studying the topic of the conclusion of those contracts in order to highlight their features and clarify the extent to which general rules accommodate the specificities of their formation; and we divided our research into an introductory section entitled "the fundamentals of block chain technology", and two main sections; the first entitled "the idea of smart contracts as a blockchain application", and the second entitled" specificity of smart contracts formation. Keywords: smart contracts, blockchain, DApps, Ethereum.
Abstract In the process of multi-cloud storage data migration, data integrity is vulnerable to corruption, but the existing data integrity verification schemes for data migration across clouds are not highly reliable. To address this problem, a blockchain-based data integrity verification scheme for migration across clouds is proposed in this paper. In this scheme, a blockchain network is used instead of a third-party auditor. For each migration, a multi-cloud broker will send an integrity verification request to blockchain at three different times, and a smart contract will verify the data integrity according to the RSA-based homomorphic verification tags. Then, the security of the scheme is analyzed. Finally, simulation experiments and tests are conducted on Ethereum, and the results show the feasibility of the scheme.
Dragoş Vicoveanu, Oana Geman, Carina Balcoș, Marius Prelipceanu
Abstract The recent use of digital Distributed Ledger Technology (DLT) in the healthcare domain can surpass the existing limitations in the centralized IT systems, such as the lack of security, access control or immutability of the electronic health information. If we discuss about clinical information, this innovative informatics advance gives back the control to the data owner. In decentralized environments, smart contracts allow trustable agreements grounded by irreversible transactions, which permit transparency and traceability. Moreover, smart contracts are the living heart of the decentralized applications that run on DTL. In this work, our attention is focused on medical equipments that helps health staff to diagnose and treat patients keeping much of their clinical data taken in dynamics. Hence, we propose a smart contract-based decentralized application framework for the management of devices, targeting also medical services, meant to facilitate the interaction of the involved entities. Our testing environment is the Ethereum platform, extensively used recently in the healthcare domain, being itself a smart operating system that allows decentralized applications to run on it.
The paper aims to clarify the relationship between Internet-of-Things devices and Ethereum blockchain. It proposes the arrangement to ensure information transmission among parties in an open system of IoT must be secure using Ethereum. The accompanying joining strategy utilized terminal gadgets as system innovation and Ethereum blockchain stage that delivered back-end, which guarantees high security, accessibility, and protection, supplanting conventional back-end frameworks. The following issues should be considered to prevent the malicious hub from attacking, resist distributed denial-of-service attacks, and prevent firmware backdoor access. This paper proposed a system in which the Peer-to-Peer authentication model, where every IoT node in the system must be authenticated and verified by the proposed framework. The paper provides empirical insights into IoT nodes manufactured in bulk, and they are remaining with their default username and password.
Bo Gao, Siyuan Shen, Ling Shi, Jiaying Li · 6 authors
Smart contracts are computerized transaction protocols built on top of blockchain networks. Users are charged with fees, a.k.a. gas in Ethereum, when they create, deploy or execute smart contracts. Since smart contracts may contain vulnerabilities which may result in huge financial loss, developers and smart contract compilers often insert codes for security checks. The trouble is that those codes consume gas every time they are executed. Many of the inserted codes are however redundant. In this work, we present sOptimize, a tool that optimizes smart contract gas consumption automatically without compromising functionality or security. sOptimize works on smart contract bytecode, statically identifies 3 kinds of code patterns, and further removes them through verification-assisted techniques. The resulting code is guaranteed to be equivalent to the original one and can be directly deployed on blockchain. We evaluate sOptimize on a collection of 1,152 real-world smart contracts and show that it optimizes 43% of them, and the reduction on gas consumption is about 2.0% while in deployment and 1.2% in transactions, the amount can be as high as 954,201 gas units per contract.
Com o avanço da tecnologia e o aparecimento da rede blockchain diversas plataformas e aplicações ganharam destaques, entre elas a plataforma Ethereum. Esta tecnologia é responsável pela criação e execução dos contratos inteligentes. O artigo apresenta os conceitos, funcionalidades e funcionamento dos contratos inteligentes e suas aplicações, assim como as principais características das tecnologias que envolvem os contratos inteligentes.
Deepesh Chaudhari, Rachit Agarwal, Sandeep K. Shukla
The temporal aspect of blockchain transactions enables us to study the address's behavior and detect if it is involved in any illicit activity. However, due to the concept of change addresses (used to thwart replay attacks), temporal aspects are not directly applicable in the Bitcoin blockchain. Several pre-processing steps should be performed before such temporal aspects are utilized. We are motivated to study the Bitcoin transaction network and use the temporal features such as burst, attractiveness, and inter-event time along with several graph-based properties such as the degree of node and clustering coefficient to validate the applicability of already existing approaches known for other cryptocurrency blockchains on the Bitcoin blockchain. We generate the temporal and non-temporal feature set and train the Machine Learning (ML) algorithm over different temporal granularities to validate the state-of-the-art methods. We study the behavior of the addresses over different time granularities of the dataset. We identify that after applying change-address clustering, in Bitcoin, existing temporal features can be extracted and ML approaches can be applied. A comparative analysis of results show that the behavior of addresses in Ethereum and Bitcoin is similar with respect to in-degree, out-degree and inter-event time. Further, we identify 3 suspects that showed malicious behavior across different temporal granularities. These suspects are not marked as malicious in Bitcoin.
Cryptoassets have experienced dramatic volatility in their prices, especially during the COVID-19 pandemic era. This pilot study explores the volatility asymmetry and correlations among three popular cryptoassets (Bitcoin, Ethereum, and Dogecoin) as well as Gold. Multiple Generalized Autoregressive Conditional Heteroskedasticity (GARCH) models are analyzed. We find that positive shocks have a greater impact on the volatility of these financial assets than negative shocks of the same magnitude, perhaps a manifestation of the fear of missing out (FOMO) effect. Our research is one of the first to use COVID-19-period volatility of financial assets (in-sample data) to forecast their later COVID-19-period volatility (out-of-sample data). This forecast accuracy is compared to that produced by forecasts using the same out-of-sample data and a longer in-sample data. Our results indicate that generally, the larger in-sample dataset gives a higher forecast accuracy though the smaller in-sample dataset is from the same regime as the out-of-sample data. We also evaluate the correlations among the assets using the Dynamic Conditional Correlation (DCC) framework and find that there is an elevated positive correlation between Gold and Bitcoin during the past two years. The Gold-Bitcoin correlation hit its peak during the peak of the COVID-19 pandemic and then fell back to around zero in July 2021 when the pandemic crisis eased. Unsurprisingly, there is a strong positive correlation among the cryptocurrencies. Pairwise correlation among all four assets was stronger during the COVID-19 pandemic. Such continuing analysis can inform portfolio asset allocation as well as general financial policy decisions.
This paper aims to build the design of a secure and trustworthy platform of digital document sharing system, where students may share their officially obtained educational documents, e.g. Certificates or Academic Transcripts, with potential employers. The system was designed on top of the Ethereum Blockchain, coupled with IPFS as the document storage system. The design has been arranged in such a way as to work as a nationwide solution.
I. S. Ivanchenko, Marina V. Charaeva, Alla A. Lysochenko, Ilya A. Nozhenkov
Since 2009, cryptocurrencies being a modern form of electronic means of payment have become widespread in the global financial market. In this regard, a study aimed to find an answer to the question: “Are cryptocurrencies a modern form of money?” was conducted. An analysis of the scientific works of leading economic schools has led to the conclusion that cryptocurrencies are a modern form of private money that performs the main monetary function being a means of payment, which corresponds to the idea of the Austrian economic school of full-fledged means of payment. The study attempts to predict the market rate of the three most popular cryptocurrencies at present being Bitcoin, Ethereum and Ripple due to the fact that modern cryptocurrencies demonstrate a high level of volatility in their market value, and reliable funds must maintain their purchasing power. The analysis of the cryptocurrency market with regard to the information efficiency has led to the conclusion that cryptocurrencies have been demonstrating instability of qualitative properties over the past five years. The authors proposed to improve the predictive characteristics of the HAR-RV model by additionally calculating the Shannon information entropy of the initial time series to level their insensitivity to unexpected information shocks in the cryptocurrency market being the main drawback of regression models. The study has proved that cryptocurrencies are a promising modern form of electronic money, their market rate is quite predictable, and the popularity of cryptocurrencies and their use in payment transactions will further increase.
Recently, phishing scams have posed a significant threat to blockchains. Phishing detectors direct their efforts in hunting phishing addresses. Most of the detectors extract target addresses’ transaction behavior features by random walking or constructing static subgraphs. The random walking methods, unfortunately, usually miss structural information due to limited sampling sequence length, while the static subgraph methods tend to ignore temporal features lying in the evolving transaction behaviors. More importantly, their performance undergoes severe degradation when the malicious users intentionally hide phishing behaviors. To address these challenges, we propose TEGDetector, a dynamic graph classifier that learns the evolving behavior features from transaction evolution graphs (TEGs). First, we cast the transaction series into multiple time slices, capturing the target address’s transaction behaviors in different periods. Then, we provide a fast nonparametric phishing detector (FD) to narrow down the search space of suspicious addresses. Finally, TEGDetector considers both the spatial and temporal evolutions toward a complete characterization of the evolving transaction behaviors. Moreover, TEGDetector utilizes adaptively learned time coefficient to pay distinct attention to different periods, which provides several novel insights. Extensive experiments on the large-scale Ethereum transaction dataset demonstrate that the proposed method achieves state-of-the-art (SOTA) detection performance. The code of TEGDetector is open sourced at https://github.com/Seaocn/TEGDetector.
This work presents how a digital identity management system can support food supply chains in guaranteeing the quality of the products marketed and the compliance of the several supply-chain’s nodes to standards and technical regulations. Specific goal of this work is to present a system that provides full visibility of process/food certifications, which nowadays are issued by accredited and approved certification bodies (issuers) and delivered and stored in paper version by the several participants (holders) of the supply chain. The system is designed and implemented by combining the latest most innovative and disruptive technologies in the market—Self Sovereign Identity system, Blockchain, and Inter Planetary File System. The crucial aspects that it aims to hit are the storage and access of food/process certifications, and the proper eligibility verification of these certifications exploiting the concepts of the Self Sovereign Identity-based models. The proposed system, realized by using standards that are WWW Consortium-compatible and the Ethereum Blockchain, ensures eligibility, transparency, and traceability of the certifications along a food supply chain, and could be an innovation model/idea that the companies that adopt the Open Innovation paradigm might want to pursue.
Vehicular Digital Forensics (VDF) is essential to enable liability cognizance of accidents and fight against crimes. Ensuring the authority to timely gather, analyze, and trace data promotes vehicular investigations. However, adversaries crave the identity of the data provider/user, damage the evidence, violate evidence jurisdiction, and leak evidence. Therefore, protecting privacy and evidence accountability while guaranteeing access control and traceability in VDF is no easy task. To address the above-mentioned issues, we propose Eunomia: an anonymous and secure VDF scheme based on blockchain. It preserves privacy with decentralized anonymous credentials without trusted third parties. Vehicular data and evidence are uploaded by data providers to the blockchain and stored in distributed data storage. Each investigation is modeled as a finite state machine with state transitions being executed by smart contracts. Eunomia achieves fine-grained evidence access control via ciphertext-policy attribute-based encryption and Bulletproofs. A user must hold specific attributes and a temporary-and-unexpired token/warrant to retrieve data from the blockchain. Finally, a secret key is embedded into data to trace the traitor if any evidence breach happens. We use a formal analysis to demonstrate the strong privacy and security properties of Eunomia. Moreover, we build a prototype in a WiFi-based Ethereum test network to evaluate its performance.
Marta Bellés-Muñoz, Barry Whitehat, Jordi Baylina, Vanesa Daza · 5 authors
Circuit-based zero-knowledge proofs have arose as a solution to the implementation of privacy in blockchain applications, and to current scalability problems that blockchains suffer from. The most efficient circuit-based zero-knowledge proofs use a pairing-friendly elliptic curve to generate and validate proofs. In particular, the circuits are built connecting wires that carry elements from a large prime field, whose order is determined by the number of elements of the pairing-friendly elliptic curve. In this context, it is important to generate an inner curve using this field, because it allows to create circuits that can verify public-key cryptography primitives, such as digital signatures and encryption schemes. To this purpose, in this article, we present a deterministic algorithm for generating twisted Edwards elliptic curves defined over a given prime field. We also provide an algorithm for checking the resilience of this type of curve against most common security attacks. Additionally, we use our algorithms to generate Baby Jubjub, a curve that can be used to implement elliptic-curve cryptography in circuits that can be validated in the Ethereum blockchain.
The purpose of this article is to examine the relationship between supply, demand and price fundamentals of Ethereum. In the paper, daily data covering the period 20.05.2017-31.01.2019 was used. Hypotheses were explained using the Classical Unit Root and ARDL Test. Respectively, the supply of Ethereum is explained by the "Ethereum Energy Consumption Index" and the demand of Ethereum is explained by "Transaction Fee". As a control variable, "Hashrate" is included in the model. Hashrate also expresses a technology used. Ethereum price is considered in Ether/USD. First, stationarity of the variables was determined using the Augmented Dickey-Fuller (ADF) test. The long-term dynamics are characterized using the Autoregressive Distributed Lag (ARDL) Bounds Test. As a result of the analysis, it was found that there is a long-term relationship between Ethereum's supply, demand, price, and Hashrate. Additionally, Ethereum price and Hashrate affect the supply of Ethereum positively in the long-term.
Non-Fungible Tokens (NFTs) leverage blockchain technology to certify and transfer ownership of digital assets to individuals. NFTs on the Ethereum blockchain have garnered significant attention recently, with a trading volume of over $2 billion in Q1 2021 only. At the same time, established NFT solutions have low flexibility, limited scalability, and high transaction fees. These deficiencies make them impractical to use at a larger scale to manage digital assets.
Traditional insurance policy settlement is a manual process that is never hassle-free. There are many issues, such as hidden conditions from the insurer or fraud claims by the insured, making the settlement process rough. This process also consumes a significant amount of time that makes the process very inefficient. This whole scenario can be disrupted by the implementation of blockchain and smart contracts in insurance. Blockchain and innovative contract technology can provide immutable data storage, security, transparency, authenticity, and security while any transaction process is triggered. With the implementation of blockchain, the whole insurance process, from authentication to claim settlement, can be done with more transparency and security. A blockchain is a virtual chain of data blocks that is a decentralized technology. Any transaction or change in the blocks is done after the decentralized validator entity, not a single person. The smart contract is a unique facility stored on the blockchain that gets executed when the predetermined conditions are met. This paper presents a framework where smart contracts are used for insurance contracts and stored on blockchain. In the case of a claim, if all the predetermined conditions are met, the transaction happens; otherwise, it is discarded. The conditions are immutable. That means there is scope for alteration from either side. This blockchain and intelligent contract-based framework are hosted on a private Ethereum network. The Solidity programming language is used to create smart contracts. The framework uses the Proof of Authority (PoA) consensus algorithm to validate the transactions. In the case of any faulty transaction request, the consensus algorithm acts according to and cancels the claim. With blockchain and smart contract implementation, this framework can solve all the trust and security issues that rely on a standard insurance policy.
<p><em>The cryptocurrency industry has exploded, with an increasing number of individuals investing in digital assets — even Malaysians who adhere to Shariah financial norms. The surge in Islamic faith members' involvement in cryptocurrencies such as Bitcoin and Ethereum has given birth to Zakat payments. Zakat is the third pillar of Islam, and it compels Muslims to make charitable contributions if they have sufficient means. The major considerations to explore are whether zakat is required on cryptocurrency investments and how the community sees zakat on cryptocurrencies. As a result, this paper will investigate the prospect of </em><em>cryptocurrencies as a digital assets</em><em> being a new source of revenue for zakat from an Islamic perspective by acquiring appropriate rulings (fatwas) and then investigating community attitudes on zakat on cryptocurrency.</em><em></em></p>
Célio Márcio Soares Ferreira, Charles Tim Batista Garrocho, Carlos Frederico Marcelo da Cunha Cavalcanti, Jorge Sá Silva · 5 authors
Blockchain is already advancing in journeys beyond cryptocurrency applications, and Ethereum, already called the world's computer, is going on a path that intends to reinvent the internet or Web 3.0, currently the leading platform for deploying so-called distributed applications (DApp). The growth of these Dapps in different spheres of society, as Smart Cities and Industry 4.0 IoT applications demand new proposals and models that integrate Ethereum and its ecosystem data with existing datasets on the traditional Web. This work presents our efforts to apply ontologies representing an Ethereum network and ecosystem using the Semantic Web model to extract and link its data. We show EthExtras a new ontology that extends and simplifies the EthOn, and as proof of concept and sample of use, we design a middleware web that exposed as RDF graphs the Ethereum data in soft real-time.
The Ethereum ecosystem was maintained by a distributed global network of computers that required massive amounts of computational power. Previous work on estimating the energy use and emissions of the Ethereum network has relied on top-down economic analysis and rough estimates of hardware efficiency and emissions factors. In this work we provide a bottom-up analysis that works from hashrate to an energy usage estimate, and from mining locations to an emissions factor estimate, and combines these for an overall emissions estimate. We analyze the entire history of PoW Ethereum, from creation to the merge.
On an Ethereum node, txpool (a.k.a. mempool) is a buffer storing unconfirmed transactions and controls what downstream services can see, such as mining and transaction propagation. This work presents the first security study on Ethereum txpool designs.
This research is the first attempt to customize a trading system that is based on second order stochastic dominance (SSD) to five known cryptocurrencies’ daily data: Bitcoin, Ethereum, XRP, Binance Coin, and Cardano. Results show that our system can predict price trends of cryptocurrencies, trade them profitably, and in most cases outperform the buy and hold (B&H) simple strategy. Our system’s best performance was achieved trading XRP, Binance Coin, Ethereum, and Bitcoin. Although our system has also generated a positive net profit (NP) for Cardano, it failed to outperform the B&H strategy. For all currencies, the system better predicted long trends than short trends.