Bitcoin ha superado la barrera psicológica de los 60.000 dólares por unidad en el mes de abril de 2021 y todo apunta a que alcanzará cotas mayores en los años venideros. Como parte del ecosistema Fintech, que está conformado por una amalgama de criptoactivos, Bitcoin es tal vez la criptomoneda más conocida junto a Ethereum, pero no la única, pues ambas son “sólo la punta del iceberg de esta transformación digital de las finanzas” (Barrio, 2021). El inexorable avance de estos criptoactivos, cuyo sustrato tecnológico se basa en blockchain, representa un desafío legal sin precedentes al que el jurista debe aproximarse desde diversos sectores normativos. Precisamente, de esta ingente labor se ocupa Moisés Barrio Andrés en la monografía Criptoactivos. Retos y desafíos normativos, que ha dirigido junto a un nutrido grupo de destacados expertos en la materia. Planteada en torno a dieciocho capítulos, el estudio abarca desde los aspectos generales inherentes a las criptofinanzas hasta las cuestiones jurídico-sustantivas y jurídico-procesales más relevantes inherentes a su circulación en el tráfico jurídico.
M. Thirunavukkarasu, Harsha Surya Abhishek Kota, Kommireddy Venkata Srinivasa Reddy
Blockchain allows transactions to be performed much faster than is possible in traditional centralized systems. To provide decentralized payment application to the users. It can be very cost effective. Using Ethereum and Solidity programming language we are creating payment application. Which will include adding functionalities such as depositing ether, gaining tokens, and withdrawing ether in exchange of tokens and also a creator fee. By using Ethereum blockchain technology we can create our own ERC20 token project. ERC20 token is a cryptocurrency built on top of the Ethereum blockchain.
Blockchain like Bitcoin and Ethereum suffer from scalability issues. Sharding\nis one of the most promising and leading solutions to scale blockchain. The\nbasic idea behind sharding is to divide the blockchain network into multiple\ncommittees, where each processing a separate set of transactions, rather than\nthe entire network processes all transactions. In this paper, we propose a\nprobabilistic approach to analyze the security of sharding-based blockchain\nprotocols. Based on this approach, we investigate the threat of Sybil attacks\nin these protocols. The key contribution of our paper is a tractable\nprobabilistic approach to accurately compute the failure probability that at\nleast one committee fails and ultimately compute the probability of a\nsuccessful attack. To show the effectiveness of our approach, we conduct a\nnumerical and comparative analysis of the proposed approach with existing\napproaches.\n
Norbert Bodziony, Paweł Jemioło, Krzysztof Kluza, Marek R. Ogiela
In recent years, blockchains systems have seen massive adoption in retail and enterprise environments. Cryptocurrencies become more widely adopted, and many online businesses have decided to add the most popular ones, like Bitcoin or Ethereum, next to Visa or Mastercard payments. Due to the decentralized nature of blockchain-based systems, there is no possible way to revert confirmed transactions. It may result in losses caused by human error or poor design of the user interface. We created a cryptocurrency wallet with a full on-chain solution for aliasing accounts and tokens to improve user experience and avoid unnecessary errors. The aliasing system consists of a number of smart contracts deployed on top of the blockchain network that give the ability to register aliases to accounts and tokens and use them instead of opaque addresses. Our solution shows how performant modern blockchains are and presents a way of building fully decentralized applications that can compete with centralized ones in terms of performance.
A good amount of effort has been dedicated to surveying and systematizing Ethereum smart contract security bug classes. There is, however, a gap in literature when it comes to surveying implementation-level security bugs that commonly occur in basic PoW blockchain node implementations, discovered during the first decade of Bitcoin's existence. This paper attempts to fill this void. In particular, if software which participates in a network by validating and generating new blocks is developed from scratch, WCGW - What Could Go Wrong? Ten broad bug type categories are listed and for each category, known examples are linked. Blockchain, as designed by the Satoshi's paper is exciting and introduces several novel bug classes which are interesting to security researchers. The paper is aimed at security testers aiming to start out in blockchain security reviews and blockchain developers as a reference on common pitfalls.
In this article, the authors develop a new analytical lens through which to examine the risk–return profiles of bitcoin, litecoin, ripple, and ethereum. Their focus is to understand better the price behavior of individual cryptocurrencies and their influence on one another. To achieve this, they segment each cryptocurrency’s time series of returns into disparate bull and bear regimes. They then examine the nature and extent of overlap between these regimes and whether they change over time. They also collect and plot several indicative distributed-denial-of-service attacks against the time series to investigate their possible impact on regime change episodes. Their findings shed light on previously unexplored systemic risk indicators within the cryptomarket as a whole and on the relationship between specific cryptocurrency pairs. These findings enhance the risk management toolkit for investors by revealing potential price behavior contagion patterns between cryptocurrencies pertinent to blended portfolio management. Furthermore, the authors’ approach serves as a blueprint for additional research into regime-type overlap within the cryptomarket. <b>TOPICS:</b>Currency, exchanges/markets/clearinghouses, financial crises and financial market history <b>Key Findings</b> ▪ Periods of overlapping regimes increase over time. The increase indicates a rise in cryptomarket systemic risk and an associated reduction in the diversification value of a blended portfolio of cryptocurrencies. ▪ Bitcoin exhibits the most favorable risk measures across both bull and bear regimes, including the lowest proclivity for extreme events during bear regimes. In contrast, ripple displays the overall riskiest profile across both regime types. ▪ Bitcoin’s regime type has the most meaningful impact on the risk–return profile of other cryptocurrencies, namely, litecoin and ripple. However, this relationship does not hold in reverse, a likely consequence of bitcoin’s market dominance and relative maturity.
Simon Joseph Aquilina, Fran Casino, Mark Vella, Joshua Ellul · 5 authors
Programming errors in Ethereum smart contracts can result in catastrophic financial losses from stolen cryptocurrency. While vulnerability detectors can prevent vulnerable contracts from being deployed, this does not mean that such contracts will not be deployed. Once a vulnerable contract is instantiated on the blockchain and becomes the target of attacks, the identification of exploit transactions becomes indispensable in assessing whether it has been actually exploited and identifying which malicious or subverted accounts were involved. In this work, we study the problem of post-factum investigation of Ethereum attacks using Indicators of Compromise (IoCs) specially crafted for use in the blockchain. IoC definitions need to capture the side-effects of successful exploitation in the context of the Ethereum blockchain. Therefore, we define a model for smart contract execution, comprising multiple abstraction levels that mirror the multiple views of code execution on a blockchain. Subsequently, we compare IoCs defined across the different levels in terms of their effectiveness and practicality through EtherClue, a prototype tool for investigating Ethereum security incidents. Our results illustrate that coarse-grained IoCs defined over blocks of transactions can detect exploit transactions with less computation; however, they are contract-specific and suffer from false negatives. On the other hand, fine-grained IoCs defined over virtual machine instructions can avoid these pitfalls at the expense of increased computation which are nevertheless applicable for practical use.
Jane Jabulile Masilela, Roscoe Bertrum Van Wyk, Nyankomo Marwa
The objective is to assess the variability of collateral crypto-assets used in secured lending on the blockchain. Using the coefficient of variation, the study estimates volatility of selected assets and implied risk intensity for both borrowers and lenders on blockchain-based lending. The coefficient of variation model was adopted by testing volatility. The model produced a number of key empirical observations from January 2017 to December 2018 reflecting market swings resulting in volatility, despite its simplicity, using Bitcoin, Ethereum and Ripple crypto-assets. The results of the study provide clarity on the crypto-assets bullish and bearish markets and whether there is a correlation between crypto-assets and Bitcoin market dominance. The recommendations include that financial institutions should de-risk their investment, participate in the crypto-currency domain and ensure financial inclusion; concepts of traditional asset-backed lending could be implemented by looking at 50 percent loan-to-value ratio.
Abstract The persevering pursuit of security has proved historically limiting the implementation of significant design improvements for Electronic Health Records (EHR). Such a vital requirement for these kinds of technical development is revamped now. This is because the patients are motivated by personalization and data science to participate in the health information sharing. The implementation of cloud computing has already shown substantial benefits for both clinical organizations and patients in managing electronic health records. The prime security issue of cloud-based electronic health records is that the patient is physically unable to own a medical record whereas a clinical organization can maintain one for them. The latter may collude with centralized cloud servers. So, there is a vulnerability of such records being tampered with in order to hide the medical malpractices. So, maintaining data integrity and data privacy becomes a significant challenge when deploying cloud computing. Therefore, in this paper, a consortium blockchain-based cloud-stored electronic health record is proposed which provides data integrity, data privacy, storage scalability, and fine-grained access control. Each process in outsourcing electronic health records to the cloud is incorporated as a transaction in a consortium ethereum blockchain through smart contracts. Through smart contracts, an attribute-based contract key is generated for the users that can decrypt the encrypted data stored in the cloud. The attribute-based contract key allows only users who are authorized to access the information ensuring data privacy and fine-grained access control. Moreover, the proposed scheme is proved to provide tamper-proof although the medical records are controlled by a group of clinical organizations.
DNS has always been criticized for its inherent design flaws, making the system vulnerable to kinds of attacks. Besides, DNS domain names are not fully controlled by the users, which can be easily taken down by the authorities and registrars. Since blockchain has its unique properties like immutability and decentralization, it seems to be promising to build a decentralized name service on blockchain. Ethereum Name Service (ENS), as a novel name service built atop Etheruem, has received great attention from the community. Yet, no existing work has systematically studied this emerging system, especially the security issues and misbehaviors in ENS. To fill the void, we present the first large-scale study of ENS by collecting and analyzing millions of event logs related to ENS. We characterize the ENS system from a number of perspectives. Our findings suggest that ENS is showing gradually popularity during its four years' evolution, mainly due to its distributed and open nature that ENS domain names can be set to any kinds of records, even censored and malicious contents. We have identified several security issues and misbehaviors including traditional DNS security issues and new issues introduced by ENS smart contracts. Attackers are abusing the system with thousands of squatting ENS names, a number of scam blockchain addresses and malicious websites, etc. Our exploration suggests that our community should invest more effort into the detection and mitigation of issues in Blockchain-based Name Services towards building an open and trustworthy name service.
Dr. J. Preetha, K. Vijay, P. Meyanandhan, K. Praveen Kumar
The blockchain technology has been an essential part due to its decentralization and security, some of its applications are decentralized voting system and transactions. The most important feature of blockchain is smart contract. The smart contract are the lines of code similar to agreement that runs on the top of blockchain to execute a process. Solidity is a common language used to design the smart contract and smart contract are stored in public database and execute automatically and cannot be changed once executed. Smart contract are not controlled by the user and they are deployed to the blockchain network and execute as programmed. Ethereum is a decentralized smart contract which runs on its own native platform.
Lim Wei Ming Shawn, P. Mohan, Peter K. K. Loh, Vivek Balachandran
In recent years, Blockchain, underpinned by distributed ledger technology (DLT) has been touted as the next disruptive technology with the potential to revolutionise various industry verticals and horizontals. Plagiarism and Intellectual Property Infringements of copyrights of artifacts, trade secrets, etc., are often fought in courts of law. There is an inherent need to adduce reliable evidence to establish a prima facie tort case or even beyond. In this paper we aim to leverage on the Blockchain technology to provide a digital transformation in the post-Covid world by offering a new platform to aid in the protection of one's intellectual property rights through a Proof of Existence (PoE) framework using Ethereum smart contracts. We have developed a seamless web platform to allow users experience a simple yet secure Proof of Existence (PoE) service by allowing the users to (i) certify, (ii) manage and (iii) view their documents securely through a digital portfolio. This PoE service leverages on the Blockchain characteristics to provide a reliable and transparent means to record a tamper-proof evidence of copyright information with timestamp as proof of existence for all its transactions through smart contracts.
Nitin Awathare, Sourav Das, Vinay J. Ribeiro, Umesh Bellur
A Blockchain system such as Ethereum is a peer to peer network where each node works in three phases: creation, mining, and validation phases. In the creation phase, it executes a subset of locally cached transactions to form a new block. In the mining phase, the node solves a cryptographic puzzle (Proof of Work-PoW) on the block it forms. On receiving a block from another peer, it starts the validation phase, where it executes the transactions in the received block in order to ensure all transactions are valid. This execution also updates the blockchain state, which must be completed before creating the next block. A long block validation time lowers the system's overall throughput and brings the well known Verifier's dilemma into play. Additionally, this leads to wasted mining power utilization (MPU).
The Covid 19 pandemic is the first major crisis facing cryptocurrencies. Therefore, the reaction of the cryptocurrency markets is important. News about epidemics affects investors' decisions. Panic index (PIndex) is an index created from news about the Covid 19 outbreak. In the study, it is used to measure the impact of decisions on the crypto money market. As cryptocurrencies, Bitcoin (BTC), Etherium (ETH), and Ripple (XRP), which have the highest transaction volume in the crypto money market, are included in the analysis. The relationship between Panic Index and the three major cryptocurrencies with the largest share in the cryptocurrency market was investigated by Ardl and Hatemi-J asymmetric causality test. Traditional causality tests acknowledge that the effects of positive and negative changes are the same. However, there may be asymmetric information and different investor behaviors in financial markets. In the study, Hatemi-J [ 1 ] Asymmetric Causality Test was conducted to examine the asymmetric relationship and symmetric relationship between Pindex and cryptocurrencies by separating them into positive and negative shocks. According to the results of the Hatemi-J causality analysis, positive shocks in the panic index are the cause of negative shocks for all cryptocurrencies. In other words, increases in the panic index are caused to fall the value of Bitcoin, Ethereum, and Ripple cryptocurrencies decrease. The results show that cryptocurrencies were not a safe haven for the investor during the Covid 19 period, as they acted similarly to other financial assets.
Yunifa Miftachul Arif, Muhammad Naufal Firdaus, Hani Nurhayati
An essential part of game development, especially in the multiplayer genre, is the scoring system. Data assurance on each device and data security is a significant issue in developing the assessment system. In this paper, our scoring system creates with blockchain-based data sharing for multiplayer games. We implemented the data design on the Unity game engine using the ethereum framework. The test results show that each device can connect to the network and can display the player's update score via the leaderboard. Some ethereum variables that affect the score data transaction process include gas prices, gas limits, and the gas used. The transaction speed test results show that the faster the gas limit value, the faster the transaction validation process will make the data transaction process faster. In this study, the gas limit value 500000 is the most optimal to get player score data transactions. While the average cost incurred for each data delivery score is 0.00996434 ETH.
Purpose This study aims to examine the volatility spillovers between Bitcoin (BTC), Litecoin (LTC) and Ethereum (ETH) as they are related to structural breaks. Design/methodology/approach This study examines the daily period from August 7, 2015 to July 10, 2018 by conducting causality-in-mean and causality-in-variance tests among cryptocurrencies. Findings The findings showed that there was one-way causality-in-mean from BTC to LTC and ETH, but there was no causality-in-mean from LTC and ETH to BTC. On the other hand, considering the structural breaks included in the variance equations, the estimation results showed that there were short-term causality-in-variance from LTC to BTC and long-term causality-in-variance from BTC to LTC. Originality/value This study fills the gap by contributing in two ways. First, to the best of the authors’ knowledge, this is the first study that used the cross-correlation function (CCF) of causality to explore causality-in-variance among cryptocurrencies. Second, this study considers the structural breaks in variance in the return series.
Chetan G. Shinde, Atharav Upare, Vishal Pawar, Ajay Raut
We propose a new blockchain-based framework for a completely decentralized stock market and bitcoin exchange in this paper. By proposing a groundbreaking framework utilizing blockchain to build a decentralized bitcoin and stock exchange network, this paper discusses the shortcomings of conventional centralized stock exchange platforms, High transaction costs, vulnerable centralized governance, and a lack of clarity in consumer behavior and algorithms are just a few of the problems. Blockchain technology consists of a large number of computer nodes that share a shared ledger securely without the need for intermediaries of any sort. The proposed blockchain-based solution addresses the disadvantages of the centralized stock exchange architecture by ensuring the integrity and security of the properties and orders of the owner, by self-enforcing intelligent agreements between parties, and by consensus algorithms, by achieving democratic and effective decisions on the execution and settlement of orders. Intelligent contracts are used in the proposed architecture to enforce the validation of the owner's rights as well as the proper execution and settlement of orders, reducing the need for a central authority to ensure that the stock exchange process is accurate. The proposed system proposes a hybrid platform that incorporates cryptocurrency and stock trading. The solution was tested for a subset of rules for the Stock Exchange by implementing a prototype in Ethereum.
As an append-only distributed database, blockchain is utilized in a vast variety of applications including the cryptocurrency and Internet-of-Things (IoT). The existing blockchain solutions show downsides in communication and storage scalability, as well as decentralization. In this article, we propose LightChain , which is the first blockchain architecture that operates over a Distributed Hash Table (DHT) of participating peers. LightChain is a permissionless blockchain that provides addressable blocks and transactions within the network, which makes them efficiently accessible by all peers. Each block and transaction is replicated within the DHT of peers and is retrieved in an on-demand manner. Hence, peers in LightChain are not required to retrieve or keep the entire ledger. LightChain is fair as all of the participating peers have a uniform chance of being involved in the consensus regardless of their influence such as hashing power or stake. We provide formal mathematical analysis and experimental results (simulations and cloud deployment) to demonstrate the security, efficiency, and fairness of LightChain , and show that LightChain is the only existing blockchain that can provide integrity under the corrupted majority power of peers. As we experimentally demonstrate, compared to the mainstream blockchains such as Bitcoin and Ethereum, LightChain requires around 66 times smaller per node storage, and is around 380 times faster on bootstrapping a new node to the system, and each LightChain node is rewarded equally likely for participating in the protocol.
Long Shi, Taotao Wang, Jun Li, Shengli Zhang · 5 authors
As the underlying consensus protocol of Bitcoin and Ethereum blockchains, Proof-of-Work (PoW) features a cryptographic mathematical puzzle whose solution is easy to verify but extremely hard to solve. Under PoW, miners maintain the security of blockchain by devoting computing powers to solve the puzzle; the miner who has solved the puzzle successfully generates a block, along with a reward (e.g., a set of cryptocurrency). The average waiting time to generate a block is inversely proportional to the computing power of the miner. To reduce the average block generation time, a group of individual miners can form a centralized mining pool to aggregate their computing power to solve the puzzle together and share the reward contained in the block. However, if the aggregated computing power of the pool forms a substantial portion of the total computing power in the network, the pooled mining undermines the core spirit of blockchain, i.e., the decentralization, and harms its security. To discourage the pooled mining, we develop a new consensus protocol called Proof-of-Age (PoA) that builds upon the native PoW protocol. The core idea of PoA lies in using Age-of-Work (AoW) to measure the effective mining periods that the miners have devoted to maintaining the security of blockchain. Unlike in the native PoW protocol, in our PoA protocol, miners benefit from its effective mining periods even if they have not successfully mined a block. We first employ a continuous time Markov chain (CTMC) to model the block generation process of the PoA based blockchain. Based on this CTMC model, we then analyze the block generation rates of the mining pool and solo miners respectively. Our analytical results verify that under PoA, the block generation rates of miners in the mining pool are reduced compared to that of solo miners, thereby disincentivizing the pooled mining. Finally, we simulate the mining process in the PoA blockchain to demonstrate the consistency of the analytical results.
First, a big data analysis of the transactions and smart contracts made on the Ethereum blockchain is performed, revealing interesting trends in motion. Next, these trends are compared with the public's interest in Ether and Bitcoin, measured by the volume of online searches. An analysis of the crypto prices and search trends suggests the existence of big players (and not the regular users), manipulating the market after a drop in prices. Lastly, a cross-correlation study of crypto prices and search trends reveals the pairs providing more accurate and timely predictions of Ether prices.