Cryptocurrencies have several features that set them aside from traditional currencies. In terms of market capitalization, the top five cryptocurrencies are considered for the analysis to strengthen the research's validation. The most successful crypto asset, being Bitcoin, possesses several characteristics that pose advantages and disadvantages in the financial markets. Digital convenience ensures the safety and ease of use for Bitcoin users, while decentralization also poses a primary benefit. Extreme volatility and the impact of negative externalities on the value of Bitcoin contribute to the assessment of Bitcoin trends in the market. The recent outbreak of the coronavirus (COVID-19) has shown evidence of influencing Bitcoin prices as the virus is spread across continents, leaving the global financial environment in turmoil. The classification of Bitcoin as a hedge is dependent on various factors, including global economic uncertainty. The extent to which the coronavirus impacts cryptocurrencies' hedging capabilities, especially that of Bitcoin’s, is of particular interest during the 2020 pandemic. Analyzing the literature on the influence of crisis on Bitcoin movement will explain why COVID-19 has had such a significant impact on the global financial markets, especially that of cryptocurrencies. The performance of Bitcoin, Ethereum, XRP, Tether, and Bitcoin Cash is compared to that of seven factors including commodities and indices: gold, USD, S&P 500 index, SSE index, world and emerging markets MSCI indices, and Economic Uncertainty, to better understand the hedging capabilities throughout the time of the crisis. This is done using four different multivariate GARCH specifications that account for the nature of the interaction between the cryptocurrencies and the financial variables. Although previous research finds that Bitcoin should act as a hedge during times of economic turmoil, the performance observed during COVID-19 suggests otherwise.
Dániel Kondor, Nikola Bulatović, József Stéger, István Csabai · 5 authors
Bitcoin and Ethereum transactions present one of the largest real-world\ncomplex networks that are publicly available for study, including a detailed\npicture of their time evolution. As such, they have received a considerable\namount of attention from the network science community, beside analysis from an\neconomic or cryptography perspective. Among these studies, in an analysis on\nthe early instance of the Bitcoin network, we have shown the clear presence of\nthe preferential attachment, or "rich-get-richer" phenomenon. Now, we revisit\nthis question, using a recent version of the Bitcoin network that has grown\nalmost 100-fold since our original analysis. Furthermore, we additionally carry\nout a comparison with Ethereum, the second most important cryptocurrency. Our\nresults show that preferential attachment continues to be a key factor in the\nevolution of both the Bitcoin and Ethereum transactoin networks. To facilitate\nfurther analysis, we publish a recent version of both transaction networks, and\nan efficient software implementation that is able to evaluate linking\nstatistics necessary for learn about preferential attachment on networks with\nseveral hundred million edges.\n
Heru Saputra, Bebby Ilham Aresta, Tri A Sundara, Ilfa Stephane · 5 authors
A diploma is a document of recognition of learning achievement from a level of education obtained after completing the study period after passing the final exam. The importance of the certificates' existence for working purposes has resulted in the proliferation of making and using fake certificates for various purposes such as applying for jobs, fulfilling the requirements to become members of the legislature, etc. The Diploma Information System using blockchain-based distributed computing can be one way to maintain the diploma's authenticity and validity. This study uses the waterfall method with several applications, ethereum remix ideas, ganache, and metamask, aiming to develop blockchain-based diploma information on STMIK Indonesia Padang by utilizing blockchain technology.
The existing crowdfunding platforms still operate using centralized system. While centralized system can operate well, it requires a third party intermediary in order to operate and thus does not completely provide data security and transparency of crowdfunding activities. In addition, the existence of a third party intermediary in a crowdfunding activity also causes the existing processing costs to be expensive. Therefore, the crowdfunding system needs to be built in a decentralized manner so that it eliminates the need for third parties as intermediaries in the crowdfunding process. This study proposes a prototype of decentralized crowdfunding system using Ethereum blockchain and smart contract technology. The result of system functionality test using black box testing method shows that all functionality of the crowdfunding system can run properly while operate in decentralized architecture.
Electing democratic representatives via voting has been a common mechanism since the 17th century. However, these mechanisms raise concerns about fairness, privacy, vote concealment, fair calculations of tally, and proxies voting on their behalf for the voters. Ballot voting, and in recent times, electronic voting via electronic voting machines (EVMs) improves fairness by relying on centralized trust. Homomorphic encryption-based voting protocols also assure fairness but cannot scale to large scale elections such as presidential elections. In this paper, we leverage the blockchain technology of distributing trust to propose a smart contract-based protocol, namely, \proto. There are many existing protocols for voting using smart contracts. We observe that these either are not scalable or leak the vote tally during the voting stage, i.e., do not provide vote concealment. In contrast, we show that FASTEN preserves voter's privacy ensures vote concealment, immutability, and avoids double voting. We prove that the probability of privacy breaches is negligibly small. Further, our cost analysis of executing FASTEN over Ethereum is comparable to most of the existing cost of elections.
Participation in permissionless blockchains results in competition over system resources, which needs to be controlled with fees. Ethereum's current fee mechanism is implemented via a first-price auction that results in unpredictable fees as well as other inefficiencies. EIP-1559 is a recent, improved proposal that introduces a number of innovative features such as a dynamically adaptive base fee that is burned, instead of being paid to the miners. Despite intense interest in understanding its properties, several basic questions such as whether and under what conditions does this protocol self-stabilize have remained elusive thus far. We perform a thorough analysis of the resulting fee market dynamic mechanism via a combination of tools from game theory and dynamical systems. We start by providing bounds on the step-size of the base fee update rule that suffice for global convergence to equilibrium via Lyapunov arguments. In the negative direction, we show that for larger step-sizes instability and even formally chaotic behavior are possible under a wide range of settings. We complement these qualitative results with quantitative bounds on the resulting range of base fees. We conclude our analysis with a thorough experimental case study that corroborates our theoretical findings.
The ecosystem inherent within currently deployed Internet of Things (IoT) systems is that of low-powered devices equipped with sensors that consume data. The data these devices collect is then stored in use-case specific applications, which are connected through application layer gateways that allow these devices to connect to third party cloud storage platforms for further processing. This stratified architecture has created data silos that introduce complexities such as limited user control and lack of solicitation regarding the usage of user data. The constant proliferation of IoT devices deployed in smart cities which include smart university campus (SUC) has resulted in the need for the development of IoT architecture models which are data-centric. In this paper a blockchain- based architecture model, and specifically, the distributed ledger inherent within the Ethereum blockchain, combined with the Proof Of Authority (POA) consensus mechanism, are proposed as a potential solution to developing a proof of concept architecture model that is data-centric. The proposed architecture model will be tested against with application specific use-cases in a simulated environment within the context of a SUC which is subsumed by a smart city.
Securing the traceability of products in a supply chain is an urgent issue. Recently, supply-chain systems that use a blockchain have been proposed. In these systems, the blockchain is used as a common database shared among supply chain parties to secure the integrity and reliability of distribution information such as ownership transfer records. These systems thus secure a high level of traceability in the supply chain. Considering future scalability of supply chains, public permissionless blockchain (PPBC) is a promising approach. In this approach, however, distribution information that should be kept private is made public since the information recorded in PPBC can be read by anyone. We therefore propose a method for preserving privacy while securing traceability in a supply chain system using PPBC. The proposed method preserves privacy by concealing distribution information via encryption. In addition, the proposed method ensures distribution among legitimate supply chain parties while concealing their blockchain addresses by using zero-knowledge proofs.We implement the proposed method on Ethereum smart contracts and verify the system behavior. The results show that the proposed method works as expected, and that system usage cost per distribution party is at most 2.2 × 106 gas units in terms of blockchain transaction fees.
Open access
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Network topology is one of the major factors in defining the behavior of a network. In the present scenario, the demand for network security has increased due to an increase in the possibility of attacks by malicious users. In this paper, a blockchain-based system is suggested for securely discovering and storing networks. Techniques such as cloud-based storage systems are not efficient and are lacking in trust, privacy, security, and data control. The blockchain-based technique suggested in this paper is capable of resolving these challenges. Experiments were performed using Mininet, Cisco Packet Tracer, and Ethereum blockchain with the network inference algorithm. This algorithm is capable of inferring the network topology even when only partial information regarding the network is available. The results obtained clearly show that the network is resistant to malicious users and various external attacks, making the network robust.
Sharding is a way to address scalability problem in blockchain technologies. Ethereum, a prominent blockchain technology, has included sharding in its roadmap to increase its throughput. The plan is also to include multiple execution environments. We address the problem of atomic cross shard value transfer in the presence of multiple execution environments. We leverage on the proposed Ethereum architecture, more specificially on Beacon chain and crosslinks, and propose a solution on top of the netted-balance approach that was proposed for EE-level atomic ðtransfers. We split a cross-shard transfer into two transactions: a debit and a credit. First, the debit transaction is processed at the source shard. The corresponding credit transaction is processed at the destination shard in a subsequent block. We use {\em netted} shard states as channels to communicate pending credits and pending reverts. We discuss various scenarios of debit failures and credit failures, and show our approach ensures atomicity even in the presence of a Byzantine Block proposer. The benefits of our approach are that we do not use any locks nor impose any constraints on the Block Proposer to select specific transactions. However we inherit the limitation of an expensive operation from the netted-balance approach of querying partial states from all other shards. We also show a bound on the size of such inter-shard state reads.
Stefan Driessen, Dario Di Nucci, Geert Monsieur, Damian A. Tamburri · 5 authors
Blockchain and smart contract technology are novel approaches to data and code management that facilitate trusted computing by allowing for development in a distributed and decentralized manner. Testing smart contracts comes with its own set of challenges which have not yet been fully identified and explored. Although existing tools can identify and discover known vulnerabilities and their interactions on the Ethereum blockchain through random search or symbolic execution, these tools generally do not produce test suites suitable for human oracles. In this paper, we present AGSOLT (Automated Generator of Solidity Test Suites). We demonstrate its efficiency by implementing two search algorithms to automatically generate test suites for stand-alone Solidity smart contracts, taking into account some of the blockchain-specific challenges. To test AGSOLT, we compared a random search algorithm and a genetic algorithm on a set of 36 real-world smart contracts. We found that AGSOLT is capable of achieving high branch coverage with both approaches and even discovered some errors in some of the most popular Solidity smart contracts on Github.
Stefan Driessen, Dario Di Nucci, Geert Monsieur, Damian A. Tamburri · 5 authors
Blockchain and smart contract technology are novel approaches to data and\ncode management that facilitate trusted computing by allowing for development\nin a distributed and decentralized manner. Testing smart contracts comes with\nits own set of challenges which have not yet been fully identified and\nexplored. Although existing tools can identify and discover known\nvulnerabilities and their interactions on the Ethereum blockchain through\nrandom search or symbolic execution, these tools generally do not produce test\nsuites suitable for human oracles. In this paper, we present AGSOLT (Automated\nGenerator of Solidity Test Suites). We demonstrate its efficiency by\nimplementing two search algorithms to automatically generate test suites for\nstand-alone Solidity smart contracts, taking into account some of the\nblockchain-specific challenges. To test AGSOLT, we compared a random search\nalgorithm and a genetic algorithm on a set of 36 real-world smart contracts. We\nfound that AGSOLT is capable of achieving high branch coverage with both\napproaches and even discovered some errors in some of the most popular Solidity\nsmart contracts on Github.\n
Stefan Driessen, Dario Di Nucci, Geert Monsieur, Willem‐Jan van den Heuvel
Blockchain and smart contract technology are novel approaches to data and code management, that facilitate trusted computing by allowing for development in a distributed and decentralized manner. Testing smart contracts comes with its own set of challenges which have not yet been fully identified and explored. Although existing tools can identify and discover known vulnerabilities and their interactions on the Ethereum blockchain through random search or symbolic execution, no framework exists for applying advanced, multi-objective algorithms to create test suites for such smart contracts. In this paper, we present AGSolT (Automated Generator of Solidity Test Suites). We demonstrate its efficiency by implementing two search algorithms to automatically generate test suites for stand-alone Solidity smart contracts, taking into account some of the blockchain-specific challenges. To test AGSolT, we compared a random search algorithm and a genetic algorithm on a set of 36 real-world smart contracts. We found that AGSolT is capable of achieving high branch overage with both approaches and even discovered some errors in some of the most popular Solidity smart contracts on Github.
Ayman Alkhalifah, Alex Ng, Paul Watters, A. S. M. Kayes
In Ethereum blockchain, smart contracts are immutable, public, and distributed. However, they are subject to many vulnerabilities stemming from coding errors made by developers. Seven cybersecurity incidents occurred in Ethereum smart contracts between 2016 and 2018, which led to financial losses estimated to be over US$ 289 million. Reentrancy vulnerability was the cause of two of these incidents, and the impacts went far beyond financial loss. Several reentrancy countermeasures are available, which are based on predefined patterns that are used to prevent vulnerability exploitation before the deployment of a smart contract; however, several limitations have been identified in these countermeasures. Motivated by all these issues, the objective of this article is to help developers improve the cybersecurity of smart contracts by proposing a solution that calculates the difference between the contract balance and the total balance of all participants in a smart contract before and after any operation in a transaction that changes its state. Proof-of-concept implementations show that this solution can provide a detection and prevention mechanism against reentrancy attacks during the execution of any smart contract.
Abstract In this study, we characterized the dynamics and analyzed the degree of synchronization of the time series of daily closing prices and volumes in US$ of three cryptocurrencies, Bitcoin, Ethereum, and Litecoin, over the period September 1,2015–March 31, 2020. Time series were first mapped into a complex network by the horizontal visibility algorithm in order to revel the structure of their temporal characters and dynamics. Then, the synchrony of the time series was investigated to determine the possibility that the cryptocurrencies under study co-bubble simultaneously. Findings reveal similar complex structures for the three virtual currencies in terms of number and internal composition of communities. To the aim of our analysis, such result proves that price and volume dynamics of the cryptocurrencies were characterized by cyclical patterns of similar wavelength and amplitude over the time period considered. Yet, the value of the slope parameter associated with the exponential distributions fitted to the data suggests a higher stability and predictability for Bitcoin and Litecoin than for Ethereum. The study of synchrony between the time series investigated displayed a different degree of synchronization between the three cryptocurrencies before and after a collapse event. These results could be of interest for investors who might prefer to switch from one cryptocurrency to another to exploit the potential opportunities of profit generated by the dynamics of price and volumes in the market of virtual currencies.
Indonesia is a densely populated country with a population of 260 million, making Indonesia the fourth most populous country in the world. The continued rapid development of the economy in Indonesia has made land an asset that provides benefits. In Indonesia, land ownership that has the highest legal power is proven by a Certificate of Ownership or in indonesian is called as Sertifikat Hak Milik (SHM). Meanwhile, the land titling process is often complex and lengthy, and because of the processing carried out by government agencies in handling a variety of different documents, some structured people commit fraud. The impact is that the model currently used does not have good governance. This research offers a Blockchain-based solution in providing data harmony and openness, lightening in data access, permanent records management, and most importantly it is a solution that is cheaper and faster. This research offers a step-by-step model of Blockchain selection beginning from the public Blockchain ledger which will continuously incorporate two degrees of Hybrid Blockchain. The smart contract design of the Public Blockchain is provided in detail as well as the use of Ethereum in implementing its prototype system. In the experimental test using the local Ethereum test network directly to show the effectiveness of the system. The results of the analysis show that the model offered can reduce the costs required for processing information, the number of trips required, and result in easy access to important information. With the implementation of Blockchain, efforts to digitize land rights in Indonesia can increase.
In this work we propose Dynamit, a monitoring framework to detect reentrancy vulnerabilities in Ethereum smart contracts. The novelty of our framework is that it relies only on transaction metadata and balance data from the blockchain system; our approach requires no domain knowledge, code instrumentation, or special execution environment. Dynamit extracts features from transaction data and uses a machine learning model to classify transactions as benign or harmful. Therefore, not only can we find the contracts that are vulnerable to reentrancy attacks, but we also get an execution trace that reproduces the attack. Using a random forest classifier, our model achieved more than 90 percent accuracy on 105 transactions, showing the potential of our technique.
Could BTCBAM Become a Strong Alternative to BITCOIN?<br> <br> BTCBAM coin is currently one of the 54 most reliable coins in the world, using the same algorithm as Bitcoin (SHA-256). While there are over 8 thousand coins / tokens in the world, it is one of the 340 coins using the blockchain platform. For this reason, it is taking firm steps towards becoming a new Bitcoin with its strong and secure infrastructure compared to ERC-20 based tokens that can be easily produced in the rapidly growing crypto money industry.<br> <br> <br> SPEKTRAL INVESTMENT BANK BTCBAM PARTNERSHIP INVESTMENT OPPORTUNITY <br> Kosovo-based Spektral Investment Bank is the first investment bank with technical and security-based capital. The Bank has a unique capital structure consisting of pre-valued exclusive license rights for pharmaceutical patents and calcite mines and pre-made reserve determination reports.<br> <br> With 800 million EU in-kind capital, the Spectral Investment Bank prioritizes bio-medical and pharmaceutical innovation and tokenization of mining securities to provide solid guarantees for high-risk cryptocurrency-based operational leverages, thus offering a significant risk reduction for dynamic financial options. This is the first real-world example of an operational merging between a cryptocurrency investment bank and a blockchain project.<br> <br> BTCBAM, one of the most successful blockchain projects developed by the Turks, signed a cooperation and collateral usage agreement with Spektral Investment Bank to establish Europe's first crypto investment exchange. Spectral Investment Bank also provides in-kind collateral guarantees for the coin, which has a total of 7 block chains to be produced by the BTCBAM team.<br> <br> Spektral Investment Bank acquired 25% of BTCBAM and Bitturex. In return, the Kosovo Investment Bank will provide full-scale project envelopes for each project to be listed on Bitturex. The bank will also provide guarantees for tokenization of projects that receive crypto funds to maximize their commercial potential.<br> <br> <br> <br> Where Can BLOCK CHAIN Technology Reach With BTCBAM? <br> The rapid development of blockchain technology and their numerous emerging applications has received huge attention in recent years. The distributed consensus mechanism is the backbone of a blockchain network. It plays a key role in ensuring the network’s security, integrity, and performance. Most current blockchain networks have been deploying the proof-of-work consensus mechanisms, in which the consensus is reached through intensive mining processes. However, this mechanism has several limitations, e.g., energy inefficiency, delay, and vulnerable to security threats. To overcome these problems, a new consensus mechanism has been developed recently, namely proof of stake, which enables to achieve the consensus via proving the stake ownership. This mechanism is expected to become a cutting-edge technology for future blockchain networks. On this whitepaper, you will learn about proof of stake mechanism and BTCBAM coin, which has a blockchain algorithm and uses a proof of stake mechanism. <br> BENEFITS AND APPLICATIONS <br> Although blockchain technology attracts a lot of attention due to the successful implementation of cryptocurrencies, its benefits extend far beyond. The key benefits of blockchain technology are as follow: <br> • Decentralization: <br> Blockchain networks are not controlled by a central controller. Thus, they do not have any single point of failure. Instead, all the nodes reach the agreement on the state of the network by participating in the distributed consensus mechanisms. <br> • Transparency: <br> Data stored in a blockchain is visible to all network participants. <br> • Immutability: <br> Once the data are stored in the blockchain, it is extremely difficult to be altered. Moreover, thanks to the distributed consensus mechanisms, the network can achieve consensus on the data even in a trustless environment. <br> • Security and Privacy: <br> Using cryptographically secure mechanisms, the privacy and security of the network participants can be significantly enhanced. Users in the network use a pair of public and private keys for identification and verification. When a user makes a transaction, a digital signature is used.<br> <br> BTCBAM TO LEAD THE DIGITAL TRANSFORMATION<br> <br> During the research and development activities that started 5 years ago, crypto money sector analyzes were made. As a result of these analyzes, two main points were determined as goals. The first of these was that in very few of the stock exchanges that provide trading services, the investment owner had its own crypto currency, and another was that coins could not find enough place in daily life. BTCBAM was built on the basis of these two goals and took its current form with the influence of other elements.<br> In this direction, the first step was to integrate the BTCBAM coin into life with its visa and master card features.<br> The BTCBAM Application is integrated with the BTCBAM coin and the exchanges it is traded on. Therefore, when you need cash, you can instantly sell your BTCBAM coins on the stock exchanges where they are traded and you can order to transfer them to your card with the mobile application when you need / want to use them.<br> BTCBAM Card is a prepaid card that is loaded with money (debit) before using it, can be spent as much as it is loaded, and allows you to shop advantageously with many member merchants. The loaded amount can be spent on the internet and at all POSs in stores. Money upload and withdrawal transactions can also be made from ATMs. You can also use it on crypto exchanges.<br> <br> <br> <br> <br> COINPAYMENTS WILL MOVE BTCBAM TO SHOPPING SITES<br> <br> Coinpayments is The World’s Most Trusted Crypto Payments Partner. Over $ 10 Billion In Crypto Payments Since 2013. Now BTCBAM coin is also included in coinpayments as a payment instrument. Thus, primarily in the crypto industry as a clearing tool<br> <br> Canadian e-commerce giant Shopify has added a series of acceptable cryptocurrencies in partnership with CoinPayments.<br> <br> Canadian e-commerce giant Shopify has partnered with CoinPayments to allow its customers to pay merchants in more than 1,800 digital currencies as opposed to an older basket of only 300, based on its ongoing partnership with BitPay. The fact that the BTCBAM coin is low in Coinpayments will also pave the way for it to be a valid coin in the Shopify infrastructure.<br> <br> BTCBAM MAKES A DIFFERENCE WITH ALTERNATIVE EARNINGS<br> <br> Among the cryptocurrencies that offer staking services and have maintained this for a long time, there are Tezos (XTZ), Cosmos (ATOM), EOS, Algorand (ALGO). In addition to these, Ethereum (ETH) is probably the most popular recently.<br> At the moment, 24 coins can be staked on the crypto money transaction platform Binance. These coins include Algorand (ALGO), TomoChain (TOMO), Harmony (ONE), DASH, Cosmos (ATOM), Polkadot (DOT) and Komodo (KMD).<br> <br> BTCBAM coin is also among the coins with staking feature. Thus, it provides its investors with the opportunity to earn additional coins with staking, as well as making a profit by investing in stock markets.<br> <br> BTCBAM coin, which is the first project of the BTCBAM team, will continue to bring new coins to the cryptocurrency sector with its strong partnership structure, Cryptocurrency Investment Bank partnership and guarantee, as well as its experience.
Andrea Lisi, Andrea De Salve, Paolo Mori, Laura Ricci · 5 authors
Recommender Systems (RSs) are becoming increasingly popular in the last years. They collect reviews concerning several types of items (e.g., shops, professionals, services, songs or videos) in order to rank them according to a given criterion, and to suggest the most relevant ones to their users. However, most of the currently used RSs exhibit two main drawbacks: they are based on a centralized control model and they do not provide reward mechanisms to encourage the participation of users. To deal with these challenges, the architectures of current RSs could be enhanced through blockchain technology, thus providing novel solutions to decentralize them. As a matter of fact, the blockchain technology could be successfully adopted in this context because smart contracts would allow the decentralization of system control, while cryptocurrency and tokens could be used to implement the reward mechanism. In the light of the above considerations, this manuscript presents a decentralized rating framework aimed to support the users of RSs based on blockchain technology, providing a token-based reward mechanism that remunerates users submitting their reviews to incentivize their participation. Moreover, the proposed system provides a flexible strategy to rank items, allowing users to choose among different functions to combine reviews to obtain item ranking. The performance and the cost of using the proposed system have been evaluated on the Ropsten Ethereum test network. For instance, our experiments have shown that the median time required to store a batch of 35 ratings is about 47 s, while the average time required to obtain the score of an item having 6000 ratings is less than 2.5 s.
Marco Ortu, Nicola Uras, Claudio Conversano, Giuseppe Destefanis · 5 authors
This work aims to analyse the predictability of price movements of cryptocurrencies on both hourly and daily data observed from January 2017 to January 2021, using deep learning algorithms. For our experiments, we used three sets of features: technical, trading and social media indicators, considering a restricted model of only technical indicators and an unrestricted model with technical, trading and social media indicators. We verified whether the consideration of trading and social media indicators, along with the classic technical variables (such as price's returns), leads to a significative improvement in the prediction of cryptocurrencies price's changes. We conducted the study on the two highest cryptocurrencies in volume and value (at the time of the study): Bitcoin and Ethereum. We implemented four different machine learning algorithms typically used in time-series classification problems: Multi Layers Perceptron (MLP), Convolutional Neural Network (CNN), Long Short Term Memory (LSTM) neural network and Attention Long Short Term Memory (ALSTM). We devised the experiments using the advanced bootstrap technique to consider the variance problem on test samples, which allowed us to evaluate a more reliable estimate of the model's performance. Furthermore, the Grid Search technique was used to find the best hyperparameters values for each implemented algorithm. The study shows that, based on the hourly frequency results, the unrestricted model outperforms the restricted one. The addition of the trading indicators to the classic technical indicators improves the accuracy of Bitcoin and Ethereum price's changes prediction, with an increase of accuracy from a range of 51-55% for the restricted model, to 67-84% for the unrestricted model.
Marco Ortu, Nicola Uras, Claudio Conversano, Giuseppe Destefanis · 5 authors
This work aims to analyse the predictability of price movements of\ncryptocurrencies on both hourly and daily data observed from January 2017 to\nJanuary 2021, using deep learning algorithms. For our experiments, we used\nthree sets of features: technical, trading and social media indicators,\nconsidering a restricted model of only technical indicators and an unrestricted\nmodel with technical, trading and social media indicators. We verified whether\nthe consideration of trading and social media indicators, along with the\nclassic technical variables (such as price's returns), leads to a significative\nimprovement in the prediction of cryptocurrencies price's changes. We conducted\nthe study on the two highest cryptocurrencies in volume and value (at the time\nof the study): Bitcoin and Ethereum. We implemented four different machine\nlearning algorithms typically used in time-series classification problems:\nMulti Layers Perceptron (MLP), Convolutional Neural Network (CNN), Long Short\nTerm Memory (LSTM) neural network and Attention Long Short Term Memory (ALSTM).\nWe devised the experiments using the advanced bootstrap technique to consider\nthe variance problem on test samples, which allowed us to evaluate a more\nreliable estimate of the model's performance. Furthermore, the Grid Search\ntechnique was used to find the best hyperparameters values for each implemented\nalgorithm. The study shows that, based on the hourly frequency results, the\nunrestricted model outperforms the restricted one. The addition of the trading\nindicators to the classic technical indicators improves the accuracy of Bitcoin\nand Ethereum price's changes prediction, with an increase of accuracy from a\nrange of 51-55% for the restricted model, to 67-84% for the unrestricted model.\n
Célio Márcio Soares Ferreira, Charles Tim Batista Garrocho, Ricardo Oliveira, Jorge Sá Silva · 5 authors
The advent of 5G will bring a massive adoption of IoT devices across our society. IoT Applications (IoT Apps) will be the primary data collection base. This scenario leads to unprecedented scalability and security challenges, with one of the first areas for these applications being Smart Cities (SC). IoT devices in new network paradigms, such as Edge Computing and Fog Computing, will collect data from urban environments, providing real-time management information. One of these challenges is ensuring that the data sent from Edge Computing are reliable. Blockchain has been a technology that has gained the spotlight in recent years, due to its robust security in fintech and cryptocurrencies. Its strong encryption and distributed and decentralized network make it potential for this challenge. Using Blockchain with IoT makes it possible for SC applications to have security information distributed, which makes it possible to shield against Distributed Denial of Service (DDOS). IoT devices in an SC can have a long life, which increases the chance of having security holes caused by outdated firmware. Adding a layer of identification and verification of attributes and signature of messages coming from IoT devices by Smart Contracts can bring confidence in the content. SC Apps that extract data from legacy and outdated appliances, installed in inaccessible, unknown, and often untrusted urban environments can benefit from this work. Our work's main contribution is the development of API Gateways to be used in IoT devices and network gateway to sign, identify, and authorize messages. For this, keys and essential characteristics of the devices previously registered in Blockchain are used. We will discuss the importance of this implementation while considering the SC and present a testbed that is composed of Blockchain Ethereum and real IoT devices. We analyze the transfer time, memory, and CPU impacts during the sending and processing of these messages. The messages are signed, identified, and validated by our API Gateways and only then collected for an IoT data management application.
Dataset retrieved with an Ethereum client, and used by the code hosted here for this paper published in the Proceedings of the Web Conference 2021 (WWW ’21) Abstract: Cryptoassets such as cryptocurrencies and tokens are increasingly traded on decentralized exchanges. The advantage for users is that the funds are not in custody of a centralized external entity. However, these exchanges are prone to manipulative behavior. In this paper, we illustrate how wash trading activity can be identified on two of the first popular limit order book-based decentralized exchanges on the Ethereum blockchain, IDEX and EtherDelta. We identify a lower bound of accounts and trading structures that meet the legal definitions of wash trading, discovering that they are responsible for a wash trading volume in equivalent of 159 million U.S. Dollars. While self-trades and two-account structures are predominant, complex forms also occur. We quantify these activities, finding that on both exchanges, more than 30% of all traded tokens have been subject to wash trading activity. On EtherDelta, 10% of the tokens have almost exclusively been wash traded. All data is made available for future research. Our findings underpin the need for countermeasures that are applicable in decentralized systems.
Mohammad Madine, Khaled Salah, Raja Jayaraman, Yousof Al-Hammadi · 6 authors
Blockchain technology has the potential to revolutionize industries by offering decentralized, transparent, data provenance, auditable, reliable, and trustworthy features. However, cross-chain interoperability is one of the crucial challenges preventing widespread adoption of blockchain applications. Cross-chain interoperability represents the ability for one blockchain network to interact and share data with another blockchain network. Contemporary cross-chain interoperability solutions are centralized and require re-engineering of the core blockchain stack to enable inter-communication and data sharing among heterogeneous blockchain networks. In this paper, we propose an application-based cross-chain interoperability solution that allows blockchain networks of any architecture type and industrial focus to inter-communicate, share data, and make requests. Our solution utilizes the decentralized applications as a distributed translation layer that is capable of communicating and understanding multiple blockchain networks, thereby delegating requests and parameters among them. The architecture uses incentivized verifier nodes that maintain the integrity of shared data facilitating them to be readable by the entities of their network. We define and describe the roles and requirements of major entities of inter-operating blockchain networks in the context of healthcare. We present a detailed explanation of the sequence of interactions needed to share an Electronic Medical Record (EMR) document from one blockchain network to another along with the required algorithms. We implement the proposed solution with Ethereum-based smart contracts for two hospitals and also present cost and security analysis for the cross-chain interoperability solution. We make our smart contracts code and testing scripts publicly available.