Services known as Cryptocurrency “Tumblers” obfuscate the provenance, possession, and movement of cryptocurrencies through a process of “mixing” . While this speaks to the cryptoanarchist philosophical roots of cryptocurrencies, it poses various forms of risks, particularly those subsumed by the anti-money laundering (AML) category. This discussion paper examines that dichotomy, between cryptoanarchism and oversight, through the Tumbler lens, so as to consider the regulation, oversight, and legality of Tumblers themselves.
The first global cryptocurrency benchmarking study presents a systematic and comprehensive picture of a rapidly evolving industry, illustrating how cryptocurrencies are being used, stored, transacted and mined. The study gathered non-public data from more than 100 cryptocurrency companies and over 30 individual cryptocurrency miners in 38 countries around the world via secure web-based questionnaires, capturing an estimated 75 per cent of the cryptocurrency industry. The study breaks down the cryptocurrency industry into four key sectors – exchanges, wallets, payments and mining. Key findings and highlights from the study include our estimate that over three million unique individuals are actively using cryptocurrency today, data on regulation and compliance practices and costs at firms, and a global map of cryptocurrency mining.
Ponzi schemes are financial frauds which lure users under the promise of high\nprofits. Actually, users are repaid only with the investments of new users\njoining the scheme: consequently, a Ponzi scheme implodes soon after users stop\njoining it. Originated in the offline world 150 years ago, Ponzi schemes have\nsince then migrated to the digital world, approaching first the Web, and more\nrecently hanging over cryptocurrencies like Bitcoin. Smart contract platforms\nlike Ethereum have provided a new opportunity for scammers, who have now the\npossibility of creating "trustworthy" frauds that still make users lose money,\nbut at least are guaranteed to execute "correctly". We present a comprehensive\nsurvey of Ponzi schemes on Ethereum, analysing their behaviour and their impact\nfrom various viewpoints.\n
In recent years, blockchain technology has attracted considerable attention. It records cryptographic transactions in a public ledger that is difficult to alter and compromise because of the distributed consensus. As a result, blockchain is believed to resist fraud and hacking. This work explores the types of fraud and malicious activities that can be prevented by blockchain technology and identifies attacks to which blockchain remains vulnerable. This study recommends appropriate defensive measures and calls for further research into the techniques for fighting malicious activities related to blockchains.
Bitcoin, a fascinating phenomenon of crypto-technology, has emerged in financial markets as a potential alternative to standard fiat currencies. It represents unique sociotechnical \necosystem working outside of any traditional markets, and its economy is still not well understood. Dynamics of Bitcoin price proves to be quite a controversial subject, but there is a strong indication that social factors mainly influence its economy. \n \nTechnical flaws and lack of any central authority issuing and controlling this digital currency make it vulnerable to abuse. It has been associated with controversy due to frequent incidents, namely hacks, theft, scam, and illicit use, which affected its ecosystem ever since it gained popularity. \n \nThis thesis adds to the discussion about social aspects of Bitcoin economy by analysing the changes in its price volatility in the context of incidents occurring in its \necosystem. As empirically proven, those negative events have no impact on the fluctuations of Bitcoin price.
Botnets, in other means zombie computers that await for instructions to execute, are the greatest threat in the internet today. They are one of the leading sources of online crime. Criminals are able to take advantage of using botnets and threaten online businesses, organizations or any entity in the internet. Criminals design and implement botnets in a complex way in order to hide their identities. Most notably the fact that criminals build command-and-control (C&C) infrastructures to manage their botnets. A botnet command-and-control mechanism (C&C) can be designed in various ways. The key principle behind designing a C&C mechanism is anonymity. Hence, criminals can propagate their instructions to botnets without revealing their identities. Since every new C&C mechanism increases the bar of anonymity, it is getting harder to trace and analyze botnets. In this thesis, we designed and implemented a C&C mechanism, btc-botnet, that runs over Bitcoin network. Btcbotnet has significant features over existing C&C mechanisms such as anonymity and resistance by its nature. We built a library that allows to use Bitcoin network as an underlying infrastructure for C&C mechanism. We evaluate our work and show that its feasibility in terms of metrics such as response time, confirmation time and fees.
J.J. Oerlemans, Bart Custers, Ronald Pool, R. Cornelisse
Het witwassen van geld dat wordt verkregen uit cybercrime vindt in de regel plaats via digitale betalingsmiddelen. De reden daarvoor is dat het geld bij cybercrime vaak wordt verkregen via online betalingsmethoden en virtuele valuta. De hoofdvraag van dit onderzoek luidt: Op welke wijze en door welke actoren wordt geld dat wordt verkregen uit banking malware en ransomware (al dan niet digitaal) witgewassen?De deelvragen van het onderzoek luiden als volgt:Wat wordt verstaan onder het witwassen van door banking malware en ransomware verkregen geld en hoe wordt witwassen juridisch gekwalificeerd?Wat zijn digitale betalingsmiddelen, in het bijzonder virtuele valuta zoals Bitcoin, en hoe werken deze digitale betalingsmiddelen?Op welke wijze en door welke actoren wordt geld witgewassen dat: a door middel van banking malware wordt verkregen? b door middel van ransomware wordt verkregen?Wat zijn de kenmerken van actoren die betrokken zijn bij het witwassen van geld dat wordt verkregen uit banking malware en ransomware?Welke informatie over de modus operandi van actoren, die betrokken zijn het bij het witwassen van geld dat verkregen wordt uit banking malware en ransomware, is beschikbaar op het dark web?Welke rol spelen digitale betalingsmiddelen, in het bijzonder virtuele valuta zoals bitcoins, bij het witwassen van geld dat wordt verkregen uit banking malware en ransomware?
Client puzzles have been proposed as a mechanism for proving legitimate intentions by providing proofs of work, which can be applied to discourage malicious usage of resources. A typical problem of puzzle constructions is the difference in expected solving time on different computing platforms. We call puzzles which can be solved independently of client computing resources fair client puzzles.
We propose a construction for client puzzles requiring widely distributed computational effort for their solution. These puzzles can be solved using the mining process of Bitcoin, or similar cryptocurrencies. Adapting existing definitions, we show that our puzzle construction satisfies formal requirements of client puzzles under reasonable assumptions. We describe a way of transforming our client puzzles for use in denial of service scenarios and demonstrate a practical construction.
Kriptovalute su digitalni novac utemeljen na kriptografiji i decentraliziranom sustavu. Postoje samo u elektroničkom obliku kao jedinstveni digitalni novčići ("tokeni"). Iza njih ne stoji autoritet države niti ih je moguće svojevoljno proizvesti. Rad se fokusira na značajkama, postavkama, razvoju i svim međuodnosima važnih ekonomskih faktora koji utječu na kriptovalute. U prvom poglavlju navedena su obilježja kriptovaluta. Drugo poglavlje daje primjere i govori o primjeni kriptovaluta u svakodnevnom životu. U trećem poglavlju je raspravljano o trenutnim i budućim regulacijama najmoćnijih zemalja svijeta (G20) , kao i njihovoj zajedničkoj suradnji u želji za jedinstvenim i standardiziranim pravilima, a sve u svrhu što kvalitetnijeg nadzora nad kriptovalutama kako bi se spriječile malverzacije i zaštitili potrošači. Četvrto poglavlje govori o inicijalnoj ponudi kovanica, a peto poglavlje je namijenjeno sigurnosti kriptovaluta. Cilj istraživanja je utvrditi koliko je studentska populacija upoznata i usmjerena prema novim oblicima digitalnog novca, koje značajke kriptovaluta smatraju pozitivnima, a koje negativnima i u kojoj su mjeri investirali ili su spremni investirati dio svojih ulaganja u kriptovalute i sl. Metode istraživanja korištene u radu su kompilacija na temelju proučavanja postojeće literature o temi rada, prikupljanje i analiza podataka vezanih uz kriptovalute, ponajprije podataka vezanih uz cijene i tržišnu kapitalizaciju, anketiranje studenata Ekonomskog fakulteta u Rijeci i metoda dedukcije putem koje su pokazane sve važne karakteristike i obilježja kriptovaluta. Na temelju provedene ankete u kojoj je sudjelovalo 90 studenata Ekonomskog fakulteta u Rijeci zaključak toga dijela istraživanja je da je mlada populacija dobro upoznata s kriptovalutama i njenim glavnim značajkama, ali i određenim nedostatkom informiranosti o tehnologiji (trećina studenata nije čula za pojam "blockchain") i nedovoljnoj odlučnosti oko investiranja i trgovanja u kriptovalute. Povrh toga, dokazan je i negativan utjecaj hakerskih napada i određenih kriminalnih radnji, kao i nestabilnost tržišne cijene na povjerenje studenata, ali i ukupne populacije vezane uz globalni financijski sustav u kriptovalute. Ishod istraživanja omogućio je da zaključimo kako su kriptovalute trenutno u ranoj fazi razvoja i nisu se dovoljno implementirale za široku primjenu u trgovini roba i usluga ili općenito kao sredstvo razmjene. Faktor koji je uključen u istraživanje kako bi opisao veličinu, odnosno obujam neke kriptovalute je tržišna kapitalizacija u dolarima. Temeljna ideja ovog rada je informirati čitatelja o pozitivnim i negativnim značajkama koje se se vežu uz kriptovalute. Na taj način čitatelji će biti bolje informirani i educirani o potencijalnom riziku ulaganja u kriptovalute, kao i većoj razini zaštite prilikom posjedovanja neke digitalne valute.
Abstract This paper is an analysis of the role reputation plays in the Deep Web using data from the Internet black-market site, The Silk Road. This encrypted online marketplace employed cryptocurrency and functioned over the Tor network. Utilizing a modeling technique, informed by trade auction theory, we investigate the effect of seller reputation. Analysis of the seller's reputation gives us insights into the factors that determine the prices of goods and services in this black marketplace. Data on cannabis listings is parsed from the Silk Road website and covers an 11-month time period, from November 2013 to October 2014. This data demonstrates that reputation acts as a sufficient self-enforcement mechanism to allow transactions. These findings exemplify the robustness of spontaneous order with respect to the Deep Web as an emergent marketplace.
Digital forensics must constantly adapt to new technological developments. The advent of Bitcoin is such a development. Bitcoin represents a new model for financial transactions. In many cash transactions between strangers, the underlying model is parties-unknown/transaction-unknown. There is no ledger record of the transaction. In contrast, PayPal illustrates the parties-known/transaction-known model. An intermediary will record both items of information. Bitcoin differs from both of these models; Bitcoin uses a parties-unknown/transaction-known model. The Bitcoin block chain records the transaction, but the user’s Bitcoin address is not expressly tied to an identity. Thus, Bitcoin users enjoy pseudo-anonymity.As the recent experience with Silk Road demonstrates, there is a downside to this pseudo-anonymity. Precisely because of that feature, Silk Road served a marketplace for vendors to sell illegal narcotics, forged identifications, and other illicit goods and services. Given that danger, law enforcement authorities have a felt need to develop techniques to penetrate the pseudo-anonymity. To do so, they have turned to digital forensics experts.This article evaluates two techniques that have been proposed for this purpose. The first is traffic analysis. This technique relies on the entry nodes that users employ to access the Internet. The second is transaction graph analysis. This technique clusters transactions to identify natural chokepoints in the Bitcoin economy, that is, service islands where, for example, the user might convert Bitcoins to fiat currency. The chokepoints becomes a target for a law enforcement subpoena to learn the user’s IP address. After describing each technique, the article assesses the research conducted to date. In particular, the article reviews Alex Biryukov’s research into traffic analysis and Sarak Meiklejohn’s work with transaction graph analysis. The article applies the standards announced in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993) to determine whether, given the available data, expert testimony based on either technique would be admissible today. The article explains that it is doubtful whether testimony based on either technique would survive a Daubert admissibility challenge. The article concludes that further research is needed to enable law enforcement authorities to effectively penetrate the pseudo-anonymity of the new parties-unknown/transaction-known model.
In dit artikel worden de mogelijke gevolgen belicht van de introductie van nieuwe en bestaande toepassingen van Bitcoin-technologie. De transnationale, decentrale en gedistribueerde peer-to-peer-structuur van de Bitcoin-technologie en van nieuwe toepassingen hiervan, hebben de potentie om bestaande sociale relaties en instituties te ontregelen. Het krachtenveld waarin maatschappelijke actoren staan kan hierdoor uit balans worden gebracht. De meest radicale van deze nieuwe technologieën is Ethereum. Met name het concept van de Digital Autonomous Organisation (DOA) heeft mogelijkerwijs verregaande consequenties. Ethereum is een ‘contract validating and enforcing system’, een gedistribueerd systeem dat een platform biedt voor autonome computerprogramma’s die in staat zijn om zelfstandig overeenkomsten met rechtspersonen en andere DOA’s aan te gaan en te ontbinden. Ik richt mij op de mogelijkheden van deze toepassingen als nieuwe platformen voor International Financial (Cyber) Crime.
Cybercriminals use cryptocurrency Bitcoin since it come to existence. It is an ideal, anonymous platform for global money transfer. Bitcoin does not have authority or central issuer, so there is no way to steal it from its holder. It is therefore used by the criminal groups around the world. This article aims to increase the reader’s knowledge on new technologies of money transfer. This knowledge will help the reader to improve the quality of personal security on the Internet. In effect it will reduce the potential risk of various types of frauds and other cybercrimes.
Bitcoins and their use are a very actual issue, especially with high popularity and high cost of Bitcoins. Number of Bitcoin’s transactions increasing day to day. But many individuals and business owners do not understand what is Bitcoin, how it works and how could it be used in business. This article discusses the nature of Bitcoin, a decentralized, anonymous and largely unregulated virtual currency, its legal status and use in business. The article includes examination of both advantages and disadvantages of Bitcoin and international regulation of legal status and taxation of this currency.
This paper focuses on the evolution of cryptocurrencies. It traces the history of early cryptography, the ‘cypherpunk’ movement, and how the work of some cyber libertarians and cryptographers enabled the emergence of popular cryptocurrencies. The paper then focuses on Bitcoin. It delves into the technology behind the Bitcoin architecture and shows how exactly this technology works. The paper then does an analysis of security and regulatory considerations that affect the growth of Bitcoin-based businesses. The paper concludes with some suggestions for future work in the area.
Feroz Ahmad Ahmad, Prashant Kumar, Gulshan Shrivastava, Med Salim Bouhlel
ON 12 JANUARY 2009 a pseudonymous entity signed a transaction that instructed a distributed network to transfer a small amount of digital currency to Hal Finney, one ofthe key figures of the cypherpunk movement. After a few minutes, the transaction was recorded on a distributed public ledger, permanently updating the balance ofbothparties. This transaction— the first Bitcoin transaction—marked the beginning of a new era of decentralized payment systems, ushering in a variety of financial Services that do not depend on any centralized clearinghouse or other financial middleman. Bitcoin is regarded by many as a powerful technological innovation that could disrupt many sectors, in the realm of finance and beyond. But the underlying technology on which the network operates, the Bitcoin blockchain can do much more than that. Just as the internet did in the early-1990s, blockchain technology carries with it a whole new range of promises concerning how decentralization can support and promote individual freedoms and autonomy. Blockchain proponents believe that Bitcoin and other cryptocurrency platforms will revolutionize mechanisms of value exchange in the same way that the internet transformed information sharing, by providing a platform for people to exchange digital resources, in a secure and decentralized manner without the need to rely on any intermediary or trusted authority. But this revolutionary potential also carries with it serious implications for censorship, intellectual property, and the regulated flow of information. A blockchain is a decentralized database of transactions maintained by a distributed network of computers, which all contribute to the verification and the validation of transactions. Once accepted, these transactions are recorded inside a “block” of transactions, which incorporates a reference to previous blocks. This creates a long chain of blocks—a “blockchain”—that stores the history of all transactions in a chronological order. Every block contains information about a particular set of transactions, a reference to the preceding block in the blockchain, and the answer to a complex mathematical puzzle that is used to validate the data associated with that block. A copy of the blockchain is stored on every computer in the network, making it virtually impossible for anyone unilaterally to modify the data stored on this decentralized database: if anyone tries to modify any transaction the fraud will be immediately detected by all other network participants.
Open access
43 source records
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
This thesis illustrates forensic research work on Bitcoin, an innovative Internet based global transaction system that attracts ascending popularity during the recent few years. As an open, public and scalable distributed payment system, Bitcoin brings forward significant economic and technological impact to our world. Meanwhile, a new notion of virtual currency, "Bitcoin" comes into existence such that Bitcoin currency can be "mined" from all over world complying with specific algorithms. Mined bit "coins" has practical monetary values that turn the Bitcoin system into a digital currency circulation system. Due to Bitcoin's decentralized semantics, Bitcoin transaction and currency are not subject to control and censorship from any single authority. Therefore, Bitcoin brings out various security concerns about its application as a long-term reliable system.\nThe research in the thesis focuses on forensic study on Bitcoin. It covers experimental study on the Bitcoin network as a peer-to-peer system and a graph-based forensic approach against Bitcoin's transaction data. Major contributions include network data evaluation and transaction history analysis. In case of forensic investigation is needed against criminal incidents such as fraud, false transactions and money theft, which are commonly seen in commonly used digital payment systems, the research provides a guidance of efficient information collection and framework of evidence data processing and extraction