Md. Nazmus Saadat, Syed Abdul Halim, Husna Osman, Rasheed Mohammad Nassr · 5 authors
<p class="Abstract"><span>Initially, blockchain is only used as a foundation of cryptocurrency, but today, we can see the rise of this new emerging technology are being implemented in many industries. In the future, most technologies around the world are expected to use blockchain as an efficient way to make online transactions. One of the areas that blockchain technologies can be applied is crowdfunding platforms. The most common problem with current crowdfunding scene in around the world including is that the campaigns are not regulated and some of the crowd-funding campaign turned out to be fraud. Besides, the completion of some projects also was significantly delayed. This project aims to solve these problems by applying Ethereum smart contracts to the crowdfunding site to that the contracts will be fully automatically executed, thus preventing frauds and ensuring that the projects can be delivered within duration given.</span></p>
This study examines whether the efficiency of cryptocurrency markets (Bitcoin and Ethereum) evolve over time based on Lo's (2004) adaptive market hypothesis (AMH). In particular, we measure the degree of market efficiency using a generalized least squares-based time-varying model that does not depend on sample size, unlike previous studies that used conventional methods. The empirical results show that (1) the degree of market efficiency varies with time in the markets, (2) Bitcoin's market efficiency level is higher than that of Ethereum over most periods, and (3) a market with high market liquidity has been evolving. We conclude that the results support the AMH for the most established cryptocurrency market.
Traditional payment systems have standards designed to keep transaction data secure, but blockchain systems are not in scope for such security standards. We compare the Payment Application Data Security Standard's (PA-DSS) applicability towards transaction-supported blockchain platforms to test the standard's applicability. By highlighting the differences in implementation on traditional and decentralized transaction platforms, we critique and adapt the standards to fit the decentralized model. In two case studies, we analyze the QTUM and Ethereum blockchain platforms' industry compliance, as their payment platforms support transactions equivalent to that of applications governed by the PA-DSS. We determine QTUM's and Ethereum's capabilities to properly ensure secure data handling with respect to current security standards. After adapting the PA-DSS and analyzing the QTUM and Ethereum platforms, we revise the new set of standards to create a set of best-practices for ensuring data security on both traditional and blockchain payment systems. We report the security gaps identified on each platform based on the final revision of the standards, presenting a conclusive perspective that neither platform is suitable for business adoption based on the PA-DSS standard's results. Finally, we discuss open research issues.
Marco Alessi, Alessio Camillò, Enza Giangreco, Marco Matera · 6 authors
Sharing personal data with service providers is a fundamental resource for the times we live in. But data sharing represents an unavoidable issue, due to improper data treatment, lack of users' awareness to whom they are sharing with, wrong or excessive data sharing from end users who ignore they are exposing personal information. The problem becomes even more complicate if we try to consider the devices around us: how to share devices we own, so that we can receive pervasive services, based on our contexts and device functionalities. The European Authority has provided the General Data Protection Regulation (GDPR), in order to implement protection of sensitive data in each EU member, throughout certification mechanisms (according to Art. 42 GDPR). The certification assures compliance to the regulation, which represent a mandatory requirement for any service which may come in contact with sensitive data. Still the certification is an open process and not constrained by strict rule. In this paper we describe our decentralized approach in sharing personal data in the era of smart devices, being those considered sensitive data as well. Having in mind the centrality of users in the ownership of the data, we have proposed a decentralized Personal Data Store prototype, which stands as a unique data sharing endpoint for third party services. Even if blockchain technologies may seem fit to solve the issue of data protection, because of the absence of a central authority, they lay to additional concerns especially relating such technologies with specifications described in the regulation. The current work offers a contribution in the advancements of personal data sharing management systems in a distributed environment by presenting a real prototype and an architectural blueprint, which advances the state of the art in order to meet the GDPR regulation. Address those arisen issues, from a technological perspective, stands as an important challenge, in order to empower end users in owning their personal data for real.
Cryptocurrencies have developed very dynamically although their future role is yet unclear. In any event, they are too big to ignore. The purpose of this article is to contribute to the understanding of cryptocurrencies in an individual and in a portfolio context. The study is based on daily closing prices of leading cryptocurrencies (Bitcoin, Ethereum, Ripple, Litecoin, and Dash) and fiat currencies (EUR, GBP, CHF, CAD, and JPY), all measured against USD. The analysis is threefold: First, the authors analyze basic statistical properties, such as correlation and autocorrelation of returns. Second, they perform a Kolmogorov–Smirnov test (KS test) and a variance ratio test (VRT) with heteroscedasticity adjustment. Third, they solve more than 4,800 optimization problems to analyze the impact of individual crypto- and fiat currencies on portfolio diversification. Among other findings, the authors find that Bitcoin, Ethereum, Dash, CAD, JPY, and EUR contribute most to reduce the variance of a mixed portfolio. In a portfolio consisting of cryptocurrencies only, Bitcoin and Ripple have the largest diversification effect. The findings provide insights for investors who focus on minimum variance portfolios or, more generally, for investors who seek to reduce return volatility exposure, as well as for monetary authorities, cryptocurrency issuers, and providers of market infrastructure. <b>TOPICS:</b>Currency, statistical methods, portfolio construction
The aim of this work is the presentation of an example of Blockchain-based technology application, which is focused on the traceability of animal origin food products. Traceability and control are automatized in a low-to-no trust environment. The implementation of smart contracts for the management of products’ shelf-life and the traceability for the consumer, using Blockchain and QR codes is discussed. Some case studies of actual implementation of these technologies are shown, and find out pros and cons of such an approach for achieving traceability of food products
Yang Xiao, Ning Zhang, Jin Li, Wenjing Lou · 5 authors
The abundance and rich varieties of data are enabling many transformative applications of big data analytics that have profound societal impacts. However, there are also increasing concerns regarding the improper use of individual data owner's private data. In this paper, we propose PrivacyGuard, a system that leverages blockchain smart contract and trusted execution environment (TEE) to enable individual's control over the access and usage of their private data. Smart contracts are used to specify data usage policy, i.e., who can use what data under which conditions and what analytics to perform, while the distributed blockchain ledger is used to keep an irreversible and non-repudiable data usage record. To address the efficiency problem of on-chain contract execution and to prevent exposing private data on the publicly viewable blockchain, PrivacyGuard incorporates a novel TEE-based off-chain contract execution engine along with a protocol to securely commit the execution result onto blockchain. We have built and deployed a prototype of PrivacyGuard with Ethereum and Intel SGX. Our experiment result demonstrates that PrivacyGuard fulfills the promised privacy goal and supports analytics on data from a considerable number of data owners.
Krishnendu Chatterjee, Amir Kafshdar Goharshady, Arash Pourdamghani
In today's cryptocurrencies, Hashcash proof of work is the most commonly-adopted approach to mining. In Hashcash, when a miner decides to add a block to the chain, she has to solve the difficult computational puzzle of inverting a hash function. While Hashcash has been successfully adopted in both Bitcoin and Ethereum, it has attracted significant and harsh criticism due to its massive waste of electricity, its carbon footprint and environmental effects, and the inherent lack of usefulness in inverting a hash function. Various other mining protocols have been suggested, including proof of stake, in which a miner's chance of adding the next block is proportional to her current balance. However, such protocols lead to a higher entry cost for new miners who might not still have any stake in the cryptocurrency, and can in the worst case lead to an oligopoly, where the rich have complete control over mining. \n \nIn this paper, we propose Hybrid Mining: a new mining protocol that combines solving real-world useful problems with Hashcash. Our protocol allows new miners to join the network by taking part in Hashcash mining without having to own an initial stake. It also allows nodes of the network to submit hard computational problems whose solutions are of interest in the real world, e.g.~protein folding problems. Then, miners can choose to compete in solving these problems, in lieu of Hashcash, for adding a new block. Hence, Hybrid Mining incentivizes miners to solve useful problems, such as hard computational problems arising in biology, in a distributed manner. It also gives researchers in other areas an easy-to-use tool to outsource their hard computations to the blockchain network, which has enormous computational power, by paying a reward to the miner who solves the problem for them. Moreover, our protocol provides strong security guarantees and is at least as resilient to double spending as Bitcoin.
Franklin Schrans, Daniel Hails, Alexander Harkness, Sophia Drossopoulou · 5 authors
The Ethereum blockchain platform supports the execution of decentralised applications or smart contracts. These typically hold and transfer digital currency to other parties on the platform; however, they have been subject to numerous attacks due to the unintentional introduction of bugs. Over a billion dollars worth of currency has been stolen since its release in July 2015. As smart contracts cannot be updated after deployment, it is imperative that the programming language supports the development of robust contracts. We propose Flint, a new statically-typed programming language specifically designed for writing robust smart contracts. Flint's features enforce the writing of safe and predictable code. To encourage good practices, we introduce protection blocks. Protection blocks restrict who can run code and when (using typestate) it can be executed. To prevent vulnerabilities relating to the unintentional loss of currency, Flint Asset traits provide safe atomic operations, ensuring the state of contracts is always consistent. Writes to state are restricted, simplifying reasoning about smart contracts.
The main goal of this article is to present a direct approach for the formula giving the long-term apparent hashrates of Selfish Mining strategies using only elementary probabilities and combinatorics, more precisely, Dyck words. We can avoid computing stationary probabilities on Markov chain, nor stopping times for Poisson processes as in previous analysis. We do apply these techniques to other block withholding strategies in Bitcoin, and then, we consider also selfish mining in Ethereum.
Blockchain is an expanding piece of technology helping us in designing and development of decentralized distributed solutions. It has impacted many industries by reducing intermediate authorities. So, we decided to explore its feasibility in the Food supply industry. The Food Agro sector has been responsible for several catastrophes, and as the industry expands globally it is strenuous to keep check and credence of and certify the food data. The fertile land for agriculture is diminishing and more yields need to be produced to content the need of the country. We propose a Blockchain based Decentralized market place where we implement a collaborative agro model between farmers and consumers. The farmers will be able to record the potential crops and the anticipated output on his farm land on the decentralized ledger. The consumers can check the information and the farmer integrity based on the previous supplies. This creates a far open and full proof digital market framework for agro-products and will help to reduce hoarding. This research paper explores one possible model of blockchain in the Food Supply Market by creating a breach proof ledger of records. We have used HTML, CSS, Javascript for frontend, Ethereum and Solidity based frameworks for backend working of this model.
Philip Daian, Steven Goldfeder, Tyler Kell, Yunqi Li · 8 authors
Blockchains, and specifically smart contracts, have promised to create fair and transparent trading ecosystems. Unfortunately, we show that this promise has not been met. We document and quantify the widespread and rising deployment of arbitrage bots in blockchain systems, specifically in decentralized exchanges (or "DEXes"). Like high-frequency traders on Wall Street, these bots exploit inefficiencies in DEXes, paying high transaction fees and optimizing network latency to frontrun, i.e., anticipate and exploit, ordinary users' DEX trades. We study the breadth of DEX arbitrage bots in a subset of transactions that yield quantifiable revenue to these bots. We also study bots' profit-making strategies, with a focus on blockchain-specific elements. We observe bots engage in what we call priority gas auctions (PGAs), competitively bidding up transaction fees in order to obtain priority ordering, i.e., early block position and execution, for their transactions. PGAs present an interesting and complex new continuous-time, partial-information, game-theoretic model that we formalize and study. We release an interactive web portal, http://frontrun.me/, to provide the community with real-time data on PGAs. We additionally show that high fees paid for priority transaction ordering poses a systemic risk to consensus-layer security. We explain that such fees are just one form of a general phenomenon in DEXes and beyond---what we call miner extractable value (MEV)---that poses concrete, measurable, consensus-layer security risks. We show empirically that MEV poses a realistic threat to Ethereum today. Our work highlights the large, complex risks created by transaction-ordering dependencies in smart contracts and the ways in which traditional forms of financial-market exploitation are adapting to and penetrating blockchain economies.
Aleksandr Kapitonov, Sergey Lonshakov, Ivan Berman, Eduardo Castelló Ferrer · 7 authors
This article describes different methods of organizing robotic services for smart cities using secure encrypted decentralized technologies and market mechanisms—as opposed to models based on centralized solutions based (or not) on using cloud services and stripping citizens of the control of their own data. The basis of the proposed methods is the Ethereum decentralized computer with the mechanism of smart contracts. In this work, special attention is paid to the integration of technical and economic information into one network of transactions, which allows creating a unified way of interaction between robots—the robot economy. Three possible scenarios of robotic services for smart cities based on the economy of robots are presented: unmanned aerial vehicles (UAVs), environmental monitoring, and smart factories. In order to demonstrate the feasibility of the proposed scenarios, three experiments are presented and discussed. Our work shows that the Ethereum network can provide, through smart contracts and their ability to activate programs to interact with the physical world, an effective and practical way to manage robot services for smart cities.
Smart contracts are applications that are deployed and executed on a blockchain's decentralised infrastructure. Many smart contract applications rely on data that resides outside the blockchain. However, while traditional web applications can communicate with trustworthy data sources directly through the Internet, this is not possible for smart contracts because their execution must be deterministic. Bringing external data into the blockchain has been a topic of research since the first introduction of Ethereum. A system that can provide this data to smart contracts is called an oracle. The primary requirement in designing oracles is that the authenticity of the data must be publicly verifiable, which can be achieved through signatures. However, transmitting data to the blockchain and performing the verification is costly, especially if applications require data from multiple sources. In that case, current approaches would need to retrieve the data from each source separately. In this paper, we present the concept of MUlti-Source oraCLE (MUSCLE) for retrieving data from multiple sources, which we believe to be the first to focus on the multi-source scenario. We implement five variants of MUSCLE, each using a different signature or aggregate signature scheme and compare their performance with two oracles that are based on TLS-N, which represents the current state of the art. Our results show that the ECDSA-based MUSCLE features the lowest total gas expenditure, while the BGLS-based oracle provides lower transaction and storage costs.
Cryptocurrency is one of the burning issues across the world in the modern era. Literature shows that business analysts always tend to use new technologies and investigate their risks. Some researchers predicted the price fluctuations and investigated the risk of cryptocurrency and blockchain network. However, to the best of our knowledge, there is no study which provides the feasibility information about locations for cryptocurrency investment around the world. This paper aims to provide the aforementioned information to the investors. The proposed methodology is based on Topic modeling along with public opinion mining about cryptocurrencies, blockchain network, bitcoin, litecoin, and ethereum. The other cryptocurrencies are not included in the study because of having insufficient relevant data on the social forums. Top locations are identified such as Australia, Denmark, Netherlands, and the USA etc. Apart from that, the public perception and environment feasibility are also determined. Almost 83.7% tweets of Sweden shows positive sentiment for cryptocurrency investment. Which ranks the highest having friendly environment for cryptocurrency investment. Similarly, the UK shows the least positive perception of cryptocurrency and blockchain technology usage. Some of the significant terms are also determined using Topic modeling from public opinions. Such as authorization rules, investment, profit, volatility, and security etc. These terms are almost identified as subtopic for each of the inquired keyword. This shows the mutual relationship among different cryptocurrencies and public's concerns about cryptocurrencies.
In this paper, we analyse the foundations of Blockchain and DAG Directed acyclic graph its evolution and the tangle, DAG try to solve the most issues in blockchain and make a system that stable for Internet-of Things (IOT) industry. In addition, to before that we need to monition Distributed ledger technology (DLT) since DLT rely on blockchain in Bitcoin and Ethereum we have this kind of issues. DAG it has special techniques from other cryptocurrencies and using different methods.
Explicit legal regulation is still lacking in many countries for cryptocurrencies like Bitcoin, Ripple, Ethereum, and others. This is not unusual for a new technology. On top of such cryptocurrencies, another new technology, so-called smart contracts, has been established. Smart contracts are specialized computer code with the aim to automate the exchange of (digital) assets. In decentralized applications (Ðapps), parts of the business logic and the data storage of traditional web applications are replaced with smart contracts. They are credited with considerable potential for commercial use, especially in FinTech but also beyond. Smart contracts mostly lack explicit legal regulation as well. Hitherto there is little experience in applying current law to them. Building a business on uncertain terrain is at least risky. We seek a clarification of smart contracts in the legal context, especially against the background of the Civil Code.
Krishnendu Chatterjee, Amir Kafshdar Goharshady, Arash Pourdamghani
In today's cryptocurrencies, Hashcash proof of work is the most commonly-adopted approach to mining. In Hashcash, when a miner decides to add a block to the chain, she has to solve the difficult computational puzzle of inverting a hash function. While Hashcash has been successfully adopted in both Bitcoin and Ethereum, it has attracted significant and harsh criticism due to its massive waste of electricity, its carbon footprint and environmental effects, and the inherent lack of usefulness in inverting a hash function. Various other mining protocols have been suggested, including proof of stake, in which a miner's chance of adding the next block is proportional to her current balance. However, such protocols lead to a higher entry cost for new miners who might not still have any stake in the cryptocurrency, and can in the worst case lead to an oligopoly, where the rich have complete control over mining.
We propose TickEth, a system that aims at mitigating some of the problems encountered by the ticketing industry. The name TickEth is built by combining the words ticket, its application domain, and Ethereum, the underlying platform we adopted for the development of the prototype.