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893 results · page 31 of 38
Savva Shanaev, Satish Kumar Sharma, Binam Ghimire, Arina Shuraeva
No abstract is available for this record.
Miles B. Gietzmann, Francesco Grossetti
No abstract is available for this record.
Rômulo Rhemo Palitot Braga, Arthur Augusto Barbosa Luna
This article analyzes some of the existing digital anonymity technologies, as well as their impact on the process and facilitation of the money laundering process. It presents the concept of superficial Internet and clarifies the difference between the Deep Web and the Dark Web, exposing how it works one of its most important operating structures, the TOR protocol. It also details the operation of BitCoin, one of the most important crypto-coins today, and draws a parallel on how these technologies can impact the practice of money laundering, as well as discusses the capacity of the mechanisms currently in place to curb and punish it. The anonymity guaranteed by the use of BitCoin is so much that in the first half of May 2017, hackers infected thousands of computers in dozens of countries, including Brazil, the United Kingdom, the United States, China, Russia, Spain and Italy, encrypting computer files and requiring redemption payment for the coded data.
Joanie Arsenault, Myriam Ertz
À la fin de l’année 2017, le cours du Bitcoin a frôlé la barre symbolique des 20 000 dollars américains,créant ainsi un intérêt grandissant de la part des milieux d’affaires, des médias, des preneurs de décision, et du grandpublic. La communauté scientifique n’est pas en reste puisque des courants de recherche entiers sur le sujet sontapparus dans des disciplines aussi variées que la finance, l’économie, le marketing, l’éthique, l’informatique ou encorele droit. L’intérêt du duo cryptomonnaies – chaîne de blocs, en général, et du Bitcoin, en particulier –, s’est toutefoislimité à l’examen des aspects techniques, des capacités transactionnelles et des implications pour le commerce et lafinance. Très peu d’études se sont penchées sur l’examen des conséquences de ces systèmes d’échange décentraliséset pair-à-pair, tels que le Bitcoin et la chaîne de blocs, sur les configurations actuelles de la gouvernance mondiale.Cet article a pour objectif de faire un compte rendu commenté de l’ouvrage collectif Bitcoin and Beyond : Cryptocurrencies,Blockchains, and Global Governance. Dans cet ouvrage, Malcolm Campbell-Verduyn met à contribution plusieursauteurs afin de mettre en lumière la manière dont la chaîne de blocs déborde du strict cadre économique et financierpour s’intégrer dans la gestion des sphères politique, légale et juridique. Ce faisant, l’ouvrage lève le voile sur denombreuses implications des cryptomonnaies et de la chaîne de blocs pour la gouvernance mondiale, souventméconnues et très peu étudiées dans la littérature, mais d’importance capitale dans un monde de plus en plusmondialisé.
Josh Kamps, Bennett Kleinberg
Pump-and-dump schemes are fraudulent price manipulations through the spread of misinformation and have been around in economic settings since at least the 1700s. With new technologies around cryptocurrency trading, the problem has intensified to a shorter time scale and broader scope. The scientific literature on cryptocurrency pump-and-dump schemes is scarce, and government regulation has not yet caught up, leaving cryptocurrencies particularly vulnerable to this type of market manipulation. This paper examines existing information on pump-and-dump schemes from classical economic literature, synthesises this with cryptocurrencies, and proposes criteria that can be used to define a cryptocurrency pump-and-dump. These pump-and-dump patterns exhibit anomalous behaviour; thus, techniques from anomaly detection research are utilised to locate points of anomalous trading activity in order to flag potential pump-and-dump activity. The findings suggest that there are some signals in the trading data that might help detect pump-and-dump schemes, and we demonstrate these in our detection system by examining several real-world cases. Moreover, we found that fraudulent activity clusters on specific cryptocurrency exchanges and coins. The approach, data, and findings of this paper might form a basis for further research into this emerging fraud problem and could ultimately inform crime prevention.
Muhammad Saad, Laurent Njilla, Charles Kamhoua, Aziz Mohaisen
Selfish mining is a well known vulnerability in blockchains exploited by miners to steal block rewards. In this paper, we explore a new form of selfish mining attack that guarantees high rewards with low cost. We show the feasibility of this attack facilitated by recent developments in blockchain technology opening new attack avenues. By outlining the limitations of existing countermeasures, we highlight a need for new defense strategies to counter this attack, and leverage key system parameters in blockchain applications to propose an algorithm that enforces fair mining. We use the expected transaction confirmation height and block publishing height to detect selfish mining behavior and develop a network-wide defense mechanism to disincentivize selfish miners. Our design involves a simple modifications to transactions' data structure in order to obtain a “truth state” used to catch the selfish miners and prevent honest miners from losing block rewards.
Simon Dyson, William Buchanan, Liam Bell
We increasingly live in a world where there is a balance between the rights to privacy and the requirements for consent, and the rights of society to protect itself. Within this world, there is an ever-increasing requirement to protect the identities involved within financial transactions, but this makes things increasingly difficult for law enforcement agencies, especially in terms of financial fraud and money laundering. This paper reviews the state-of-the-art in terms of the methods of privacy that are being used within cryptocurrency transactions, and in the challenges that law enforcement face.
Wesley Joon-Wie Tann, Xing Han, Sourav Sen Gupta, Yew-Soon Ong
No abstract is available for this record.
Moisés Toapanta, José Mero, Dario Huilcapi, Máximo Giovani Tandazo Espinoza · 6 authors
It was analysed in a general way and the security problem of the public organizations of Ecuador was determined. The objective is to generate a prototype in a blockchain diagram, based on an algorithm using flowchart techniques to provide robustness against failures, third-party attacks and mitigate information vulnerabilities. The deductive and exploratory research method was used in order to analyse the information available in the medium and scientific articles. Resulted an algorithm developed through flow diagram techniques to improve the processing of information in a public organization in Ecuador from the use of the Blockchain technology and the use of the SHA 256 algorithm. It was concluded that access to the data to a generic public organization of Ecuador will have an alternative to improve the security of the information with the implementation of the blockchain.
Yuen C Lo, Francesca Medda
Bitcoin is the world’s leading cryptocurrency, with a market capitalization briefly exceeding $300 billion. This hints at Bitcoin’s \namorphous nature: is this a monetary or a corporate measure? Hard values become explicit in the processing of transactions and \nthe digital mining of Bitcoins. Electricity is a primary input cost. Bitcoins earned are often used to circumvent local currency \ncontrols and acquire US dollars. For the period August 2010 to February 2018, we examine the components of Bitcoin mining \nrevenues, their statistical contribution to daily changes, and to its variance. We provide evidence that Bitcoin transaction processing \nis capacity constrained.
Silivanxay Phetsouvanh, Frédérique Oggier, Anwitaman Datta
The Bitcoin network is a complex network that records anonymous financial transactions while encapsulating the relationships among its pseudonymous users. This paper proposes graph mining techniques to explore the relationships among wallet addresses (pseudonyms for Bitcoin users) suspected to be involved in a given extortion racket, exploiting the anonymity of the Bitcoin network to collect and launder money. Starting around Bitcoin addresses of potential interest, neighborhood subgraphs are analyzed in terms of path length and confluence to detect suspicious Bitcoin flow and other wallet addresses controlled by the suspected perpetrators. We show with a dataset of the Ashley Madison blackmail campaign from August 2015 how the mechanisms can be used both to estimate the amount of money that was extorted by the suspected perpetrators under the specific blackmail campaign, and also estimate the amount of money handled by them during the same period of time.
Maxime Lambrecht, Louis Larue
How promising is Bitcoin as a currency? This paper discusses four claims on the advantages of Bitcoin: a more stable currency than state-backed ones; a secure and efficient payment system; a credible alternative to the central management of money; and a better protection of transaction privacy. We discuss these arguments by relating them to their philosophical roots in libertarian and neoliberal theories, and assess whether Bitcoin can effectively meet these expectations. We conclude that despite its advocates' enthusiasm, there are good reasons to doubt that Bitcoin can fulfill its promises and act as a functioning currency, rather than as a mere speculative asset.
Haaroon Yousaf, George Kappos, Sarah Meiklejohn
One of the defining features of a cryptocurrency is that its ledger, containing all transactions that have ever taken place, is globally visible. As one consequence of this degree of transparency, a long line of recent research has demonstrated that--even in cryptocurrencies that are specifically designed to improve anonymity--it is often possible to track money as it changes hands, and in some cases to de-anonymize users entirely. With the recent proliferation of alternative cryptocurrencies, however, it becomes relevant to ask not only whether or not money can be traced as it moves within the ledger of a single cryptocurrency, but if it can in fact be traced as it moves across ledgers. This is especially pertinent given the rise in popularity of automated trading platforms such as ShapeShift, which make it effortless to carry out such cross-currency trades. In this paper, we use data scraped from ShapeShift over a thirteen-month period and the data from eight different blockchains to explore this question. Beyond developing new heuristics and creating new types of links across cryptocurrency ledgers, we also identify various patterns of cross-currency trades and of the general usage of these platforms, with the ultimate goal of understanding whether they serve a criminal or a profit-driven agenda.
Tyler Moore, Nicolas Christin, Janos Szurdi
Bitcoin has enjoyed wider adoption than any previous cryptocurrency; yet its success has also attracted the attention of fraudsters who have taken advantage of operational insecurity and transaction irreversibility. We study the risk that investors face from the closure of Bitcoin exchanges, which convert between Bitcoins and hard currency. We examine the track record of 80 Bitcoin exchanges established between 2010 and 2015. We find that nearly half (38) have since closed, with customer account balances sometimes wiped out. Fraudsters are sometimes to blame, but not always. Twenty-five exchanges suffered security breaches, 15 of which subsequently closed. We present logistic regressions using longitudinal data on Bitcoin exchanges aggregated quarterly. We find that experiencing a breach is correlated with a 13 times greater odds that an exchange will close in that same quarter. We find that higher-volume exchanges are less likely to close (each doubling in trade volume corresponds to a 12% decrease in the odds of closure). We also find that exchanges that derive most of their business from trading less popular (fiat) currencies, which are offered by at most one competitor, are less likely to close.
Miguel Ángel Vázquez-Gutiérrez
El objetivo de esta investigación fue saber si realmente las inversiones en el Bitcoin son riesgosas o no, y conocer más acerca de este nuevo mercado de Monedas Virtuales. Esta investigación se llevó acabo de manera documental, analizando la información disponible en el campo para así buscar la principal causa de incertidumbre de este mercado internacional, y conocer así sus principales ventajas y desventajas, con esto identificar si son riesgosas o no, y así poder ayudar a los lectores a tener una mejor y más sencilla idea, sobre este mercado para saber si la inversión resultara o no. Los resultados mostraron que invertir en este momento en Bitcoins no es lo más indicada, pero en un futuro, no muy lejano, este mercado será más estable y seguro para hacer cualquier tipo de inversión y transacción.
Ahmet Faruk Aysan, Ender Demir, Giray Gözgör, Chi Keung Marco Lau
No abstract is available for this record.
Shaen Corbet, Brian M. Lucey, Andrew Urquhart, Larisa Yarovaya
No abstract is available for this record.
Raphael Auer, Stijn Claessens
Cryptocurrencies are often thought to operate out of the reach of national regulation, but in fact their valuations, transaction volumes and user bases react substantially to news about regulatory actions. The impact depends on the specific regulatory category to which the news relates: events related to general bans on cryptocurrencies or to their treatment under securities law have the greatest adverse effect, followed by news on combating money laundering and the financing of terrorism, and on restricting the interoperability of cryptocurrencies with regulated markets. News pointing to the establishment of specific legal frameworks tailored to cryptocurrencies and initial coin offerings coincides with strong market gains. These results suggest that cryptocurrency markets rely on regulated financial institutions to operate and that these markets are segmented across jurisdictions, bringing cryptocurrencies within reach of national regulation.
Libing Fang, Elie Bouri, Rangan Gupta, David Roubaud
We assess whether the long-run volatilities of Bitcoin, global equities, commodities, and bonds are affected by global economic policy uncertainty. Empirical results provide evidence supporting that, except for the case of bonds. We further examine whether the correlation between Bitcoin and global equities, commodities, and bonds are affected by global economic policy uncertainty and the results reveal that global economic policy uncertainty has a negative significant impact on the Bitcoin-bonds correlation, and a positive impact on both Bitcoin-equities and Bitcoin-commodities correlations, suggesting a possibility for Bitcoin to act as a hedge under specific economic uncertainty conditions. Interestingly, the hedging effectiveness of Bitcoin for both global equities and global bonds enhances slightly after considering the level of global economic policy uncertainty. Implications for investors and policy-makers are discussed.
HPUILS, Gitanjali Thapar, Pushpanjali Chandel
No abstract is available for this record.
Shenglan Ma, Hao Wang, Hong‐Ning Dai, Shuhan Cheng · 6 authors
Risk and Information System Control Framework in business includes the methods and processes to manage risks and seize opportunities which involve identifying particular risk events relevant to the objectives, assessing them in terms of likelihood and magnitude of impact, determining a response strategy, and monitoring progress. In order to provide better support for the backtracking, traceability, irreversibility, and credible requirements of risk registration table data in the framework, this paper proposes a blockchain-based risk and information system control framework. A risk association tree is designed for combining summarized risk item ledgers with risk assessment ledgers and risk response ledgers based on the Merkle Tree. Three proposed smart contracts are used in risk identification, risk assessment, risk response and mitigation, and risk and control monitoring and reporting processes. We implement a prototype for this framework.
Sagwadi Mabunda
Virtual currencies are on the rise and so is money laundering. While there are efforts to combat money laundering through various intergovernmental bodies, many have expressed concern over the rise of virtual currencies. Some cryptocurrencies such as Bitcoin have played a major role in the proliferation of online money laundering as it possesses characteristics that criminals are fond of. Bitcoin and other cryptocurrencies are decentralised, anonymous/pseudonymous and irreversible. They provide the means to skirt the Anti-Money laundering safeguards that have been put in place. \nThis paper discusses the intersection between Anti-Money Laundering efforts and the challenges that are introduced by cryptocurrencies such as Bitcoin. It also looks at the case of Liberty Reserve to highlight these challenges.
Johannes Krupp, Christian Rossow
Cryptocurrencies like Bitcoin not only provide a decentralized currency, but also provide a programmatic way to process transactions. Ethereum, the second largest cryptocurrency next to Bitcoin, is the first to provide a Turing-complete language to specify transaction processing, thereby enabling so-called smart contracts. This provides an opportune setting for attackers, as security vulnerabilities are tightly intertwined with financial gain. In this paper, we consider the problem of automatic vulnerability identification and exploit generation for smart contracts. We develop a generic definition of vulnerable contracts and use this to build TEE THER, a tool that allows creating an exploit for a contract given only its binary bytecode. We perform a large-scale analysis of all 38,757 unique Ethereum contracts, 815 out of which our tool finds working exploits for—completely automated.
Bart Custers, Ronald Pool, R. Cornelisse
Banking malware is malicious software that aims to steal money from victims via manipulated bank transfers in online banking. This paper describes how the profits of banking malware are generated and subsequently laundered, with a particular focus on the use of bitcoins and other digital payment methods. Computers are infected with banking malware via phishing emails, in which people are persuaded in various ways to click on links or open attachments, or via exploit kits, programs that try to find weak spots in the security of computer systems. After infection, bank transfers of the online banking accounts of victims are manipulated via fake website screens (web injects). Behind the screens the amounts and beneficiaries of transactions are modified, emptying the victims’ bank accounts. In the next step, the banking malware profits are laundered. In this paper we describe two models that are used in particular (next to more traditional money laundering methods). The first model involves the use of money mules and a quick cash-out. The second model focuses on direct spending via (a) direct purchases of products via online shopping, (b) direct purchases of bitcoins via Bitcoin exchanges or (c) direct purchases of luxury goods. Bitcoins can be further laundered via so-called mixing services. All in all, these methods allow criminals to launder profits in relative anonymity and prevent seizure of the illegal profits.