Bitcoin was not the first attempt at a digital currency, but it has been the most successful and it is now being accepted by a number of major retailers. Bitcoin is a cryptocurrency and operates as a peer-to-peer network. Its security is guaranteed by cryptographic algorithms instead of governments and has the potential to become a major means of payment for e-commerce and may even materialize as a viable challenge to traditional money-transfer providers. Instead of serving one country or some countries, Bitcoin serves the entire world.
We consider sequences of games $\mathcal{G}=\{G_1,G_2,\ldots\}$ where, for all $n$, $G_n$ has the same set of players. Such sequences arise in the analysis of running time of players in games, in electronic money systems such as Bitcoin and in cryptographic protocols. Assuming that one-way functions exist, we prove that there is a sequence of 2-player zero-sum Bayesian games $\mathcal{G}$ such that, for all $n$, the size of every action in $G_n$ is polynomial in $n$, the utility function is polynomial computable in $n$, and yet there is no polynomial-time Nash equilibrium, where we use a notion of Nash equilibrium that is tailored to sequences of games. We also demonstrate that Nash equilibrium may not exist when considering players that are constrained to perform at most $T$ computational steps in each of the games $\{G_i\}_{i=1}^{\infty}$. These examples may shed light on competitive settings where the availability of more running time or faster algorithms lead to a "computational arms race", precluding the existence of equilibrium. They also point to inherent limitations of concepts such "best response" and Nash equilibrium in games with resource-bounded players.
The use of Bitcoin as an alternative to traditional “flat” currency is “unnerving precisely because a world where it is used for all transactions is one where the ability of a central bank to guide the economy is destroyed, by design.” Bitcoin, the first decentralized digital currency, is a peer-to-peer payment system that allows international transactions to take place at any hour and in any place for very low cost. This Note analyzes Bitcoin and ultimately proposes a short-term solution to Bitcoin’s regulatory uncertainty that aims to strike a balance between the government’s interest in regulation and Bitcoin’s rejection of central authority – a loosely defined legal framework that operates with a minimal degree of governmental intervention.
The emergence of Bitcoin as a means to make electronic transactions directly across a peer-to-peer network has sparked interest from many fields, mostly due to its capability to handle such transactions on a large scale, with no recourse to centralised structures of management. This is achieved through its underlying technical architecture, the ‘block chain’: an impressively robust system of recording transactions on a network that’s security is guaranteed via the distribution of all transaction data (in blocks) to every node in the system on an ever-increasing chain. Last year saw the emergence of ‘Bitcoin 2.0’ applications, where vast amounts of investment capital flowed into projects that proposed to develop systems that offer a diverse range of applications beyond crypto-currencies, such as voting systems, electronic contracts, financial services, and identification recognition. What unifies these projects is the desire to replace centralised, human-run organisations, with cryptographically secure, automated peer-to-peer systems. Within this desire is a political vision, a vision that is not at all homogenous, nor harmonious, but nonetheless contains central elements that can be traced in the formation of Bitcoin. This paper seeks to explore this vision, drawing on primary research data to examine the technical politics of crypto-currencies. Bitcoin first appeared as a white paper published on The Cryptography Mailing List at metzdowd.com, an open mailing list associated with the internet subculture of cypherpunks – a subculture that fused concerns over increasing state intrusion into everyday life through rapidly growing electronic surveillance, with the open source principles that challenge proprietary software, declare digital technology to be a public good, and thus endeavour to provide alternatives. These values are indeed reflected in Bitcoin’s white paper, and through its public release as an open source project. In the wake of the 2008 financial crisis, and ongoing revelations about coordinated programs of mass state surveillance, many have begun to see Bitcoin as a potentially important public tool. But how exactly, can radical values be embedded in technology? And how does its diffusion among different contexts, and development for different purposes, affect this radical potential? In these respects, I believe it is important to consider the work of Andrew Feenberg. At the crux of Feenberg’s critical theory is the concept of hegemonic technological rationality which, through a dominant form of reasoning, enframes how we understand technology; and through dominant systems of production, entails the exclusion of the interests of marginal social groups. This has the effect of reproducing dominant hegemonic social values through the practices that consequently prosper in this system, practices that structure much of social life and impinge on environments. Feenberg does however, identify two means for subverting this process: democratic intervention on the part of social groups campaigning for alternative technologies; and tactical practices in which marginal groups can reveal alternative potentialities for technology by finding new ways of appropriating the technologies around them. In the collective and voluntary efforts of disparate developers unified by the conviction that digital technologies are and should be a public good – and not proprietary tools of corporate profiteering and state surveillance – we see this latter form of tactical resistance embodied in the origins of Bitcoin. Bitcoin thus opens up alternative possibilities for technological progress, both in ideological and material ways. Materially, Bitcoin opens up further potentialities for tactical practices, as we are seeing with the various ways in which block chain technology is being adapted. Ideologically, Bitcoin introduces its users to systems of thought that challenge dominant understandings of financial technologies and the social structures they support. In this latter sense, Bitcoin has the potential to be a counter-hegemonic force. In this paper however, I will present data that suggests this is not the case, and that in fact Bitcoin is reinforcing the dominant ideals of neoliberalism. In presenting the details of this process, I aim to demonstrate the importance of understanding the development of ‘cultures of knowledge’ that emerge around contemporary technological practices. References and Notes Feenberg, A. (1991) A Critical Theory of Technology . Oxford: University Press Feenberg, A. (1999) Questioning Technology. London: Routledge
Actuality and purpose of work. Bitcoin is a currency that exists only virtually and has appeared due to the global financial crisis and development of technologiesof technologies. Cashless payments become more popular and in this context e-commerce has improved. There were Aanalized the ysis of bitcoin perspectives in the banking system, by emphasizing analyzing the strengths and weaknesses of this currency and the point of view of investors, central banks and commercial banks. The methods used. The methodological approaches used bymentioned in special literature were used. The results of the work. Analysis can be used to improve electronic commerce and cashless payments in Moldova, where cash is still very widely used.
Bitcoin has emerged as phenomenon of the financial markets as the currency without any central authority. Recent events of Bitcoin has risen question about its behavior and there is crucial question if the price of Bitcoin follows hypothesis of efficient markets. In this paper, there are introduced the main features of Bitcoin and analyzed its price behavior. We found out that price of the most famous cryptocurrency Bitcoin follows the hypothesis of efficient markets and it immediately react on publicly announce information. Furthermore, Bitcoin can be seen as standard economic good that is priced by interaction of supply and demand on the market. These factors can be driven by macro financial development or by speculative investors, but there weren’t found any significant impact of these factors on price of Bitcoin.
We survey recent results on the mathematical stability of Bitcoin protocol. Profitability and probability of a double spend are estimated in closed form with classical special functions. The stability of Bitcoin mining rules is analyzed and several theorems are proved using martingale and combinatorics techniques. In particular, the empirical observation of the stability of the Bitcoin protocol is proved. This survey article on the mathematics of Bitcoin is published by the Newsletter of the European Mathematical Society, vol.115, 2020, p.31-37. Continuation of arXiv:1601.05254 (EMS Newsletter, 100, 2016 p.32).
This thesis is devoted to low-resource off-path deanonymisation techniques for two popular systems, Tor and Bitcoin. Tor is a software and an anonymity network which in order to confuse an observer encrypts and re-routes traffic over random pathways through several relays before it reaches the destination. Bitcoin is a distributed payment system in which payers and payees can hide their identities behind pseudonyms (public keys) of their choice. The estimated number of daily Tor users is 2,000,000 which makes it arguable the most used anonymity network. Bitcoin is the most popular cryptocurrency with market capitalization about 3.5 billion USD. In the first part of the thesis we study the Tor network. At the beginning we show how to remotely find out which Tor relays are connected. This effectively allows for an attacker to reduce Tor users' anonymity by ruling out impossible paths in the network. Later we analyze the security of Tor Hidden Services. We look at them from different attack perspectives and provide a systematic picture of what information can be obtained with very inexpensive means. We expose flaws both in the design and implementation of Tor Hidden Services that allow an attacker to measure the popularity of arbitrary hidden services, efficiently collect hidden service descriptors (and thus get a global picture of all hidden services in Tor), take down hidden services and deanonymize hidden services. In the second part we study Bitcoin anonymity. We describe a generic method to deanonymize a significant fraction of Bitcoin users and correlate their pseudonyms with their public IP addresses. We discover that using Bitcoin through Tor not only provides limited level of anonymity but also exposes the user to man-in-the middle attacks in which an attacker controls which Bitcoin blocks and transactions the user is aware of. We show how to fingerprint Bitcoin users by setting an "address cookie" on their computers. This can be used to correlate the same user across different sessions, even if he uses Tor, hidden-services or multiple proxies. Finally, we describe a new anonymous decentralized micropayments scheme in which clients do not pay services with electronic cash directly but submit proof of work shares which the services can resubmit to a crypto-currency mining pool. Services credit users with tickets that can later be used to purchases enhanced services.
In standard Walrasian auctions, the price of a good is defined as the point where the supply and demand curves intersect. Since both curves are generically regular, the response to small perturbations is linearly small. However, a crucial ingredient is absent of the theory, namely transactions themselves. What happens after they occur? To answer the question, we develop a dynamic theory for supply and demand based on agents with heterogeneous beliefs. When the inter-auction time is infinitely long, the Walrasian mechanism is recovered. When transactions are allowed to happen in continuous time, a peculiar property emerges: close to the price, supply and demand vanish quadratically, which we empirically confirm on the Bitcoin. This explains why price impact in financial markets is universally observed to behave as the square root of the excess volume. The consequences are important, as they imply that the very fact of clearing the market makes prices hypersensitive to small fluctuations.
A peer-to-peer network, enabling different parties to jointly store and run computations on data while keeping the data completely private. Enigma's computational model is based on a highly optimized version of secure multi-party computation, guaranteed by a verifiable secret-sharing scheme. For storage, we use a modified distributed hashtable for holding secret-shared data. An external blockchain is utilized as the controller of the network, manages access control, identities and serves as a tamper-proof log of events. Security deposits and fees incentivize operation, correctness and fairness of the system. Similar to Bitcoin, Enigma removes the need for a trusted third party, enabling autonomous control of personal data. For the first time, users are able to share their data with cryptographic guarantees regarding their privacy.
The availability of data on digital traces is growing to unprecedented sizes, but inferring actionable knowledge from large-scale data is far from being trivial. This is especially important for computational finance, where digital traces of human behavior offer a great potential to drive trading strategies. We contribute to this by providing a consistent approach that integrates various datasources in the design of algorithmic traders. This allows us to derive insights into the principles behind the profitability of our trading strategies. We illustrate our approach through the analysis of Bitcoin, a cryptocurrency known for its large price fluctuations. In our analysis, we include economic signals of volume and price of exchange for USD, adoption of the Bitcoin technology, and transaction volume of Bitcoin. We add social signals related to information search, word of mouth volume, emotional valence, and opinion polarization as expressed in tweets related to Bitcoin for more than 3 years. Our analysis reveals that increases in opinion polarization and exchange volume precede rising Bitcoin prices, and that emotional valence precedes opinion polarization and rising exchange volumes. We apply these insights to design algorithmic trading strategies for Bitcoin, reaching very high profits in less than a year. We verify this high profitability with robust statistical methods that take into account risk and trading costs, confirming the long-standing hypothesis that trading based social media sentiment has the potential to yield positive returns on investment.
In het Delta Lloyd magazine april 2015, p. 32, wordt aandacht besteed aan Martijn Wismeijer (43 jaar). Hij liet onlangs twee chips onder zijn huid implanteren, een voor bitcoins en een voor de honderden wachtwoorden die hij voor digitale toepassingen gebruikt. 1 Het is een feit dat we in het huidige ICT-tijdperk te maken krijgen met heel veel wachtwoorden die liefst zo weinig mogelijk identiek mogen zijn en het is duidelijk dat wie toegang krijgt tot die wachtwoorden ons leven behoorlijk kan ontwrichten. Maar is een chip voor bitcoins niet overbodig? Wat zijn bitcoins eigenlijk, wat is hun juridische status en zijn ze betaalmiddel?
The aim of this article is to show the position of Bitcoin among virtual currencies. On the basis of the reports published by the European Central Bank and The Financial Action Task Force, as well as the available Internet and primary sources, there have been presented the types and the history of virtual currencies, the way in which Bitcoin functions and the methods of acquiring it. The article is based on the assumption that an in-depth knowledge of virtual currencies, their classification and their functioning will make it possible to regulate their legal status. It is necessary not only for tax purposes, but also in order to avoid the risk of using this payment method for terrorist or criminal purposes. The knowledge of the history of virtual currencies also makes it possible to foresee the problems that may hinder the functioning of Bitcoin and other virtual currencies. The growing popularity of virtual currencies and cryptocurrencies is linked with the increase of importance of non-cash payments on global scale. Thus, Bitcoin may be considered a next step in the evolution of digital money.
Victor Ranieri Bomfim Sampaio de Araújo, Márcia Reis Machado Machado
Bitcoins are in use today to do transitions. There are companies that accept Bitcoins as payment whem supply goods and services. However there isn’t currency status. It’s made of mathematics equations that its transactions are validated through encryption, hash function, p2p network and proof-of-work. Like a currency that just exists in the virtual form it needs the user’s confidence for have a valour. Although the large growth since your creation, in 2008, and be considered for many a big evolution, in the informatic and business fields, some entities and researchers say the Bitcoins are a ponzi scheme. This research aims to describe the transitions that envolve cripto-currency and the suitable accounting treatment in Brazil, based on the current standards. For this was done a general analysis that shows the best classifications as Contingent Asset, because their uncertainty value and their uncertainty existence too. The second section of the analysis was done hypothetical situations. The first was the mining situation, then the receive bitcoins as payment and finished with the company had bought that. Because it’s a Contingent Asset was generated a conflict on the two last situations. But for that was suggested an account on the current asset that represent the expectative to generate future cash flows when liquidate the Bitcoins without excluding the disclosure in the notes as Contingent Asset. Lastly was concluded that the risks associated with property losses and the association with illicit activity, beyond that there are so many indications that is a ponzi scheme and even it isn’t, there are not perspective for their operation.
In this chapter, we discuss economic aspects of cryptocurrencies. 4.1. The double spending problem 4.2. How does Bitcoin work? Brief overview 4.3. Not the first one – predecessors of Bitcoin 4.4. Problems with Bitcoin (new challenges) 4.5. Competition against other crypto-currencies 4.6. Non-currency use of blockchain technology 4.7. Trading cryptocurrencies 4.8. How do crypto-currencies’s attributes compare to earlier money? For Chapter 1 (Introduction), see https://ssrn.com/abstract=3135021. For Chapter 2 (Means of Exchange: Ever-present Competition), see https://ssrn.com/abstract=3135028. For Chapter 3 (Platform-based Currencies), see https://ssrn.com/abstract=3135030. For Chapter 5 (Conclusions), see https://ssrn.com/abstract=3135057.
Current cryptocurrencies, starting with Bitcoin, build a decentralized blockchain-based transaction ledger, maintained through proofs-of-work that also serve to generate a monetary supply. Such decentralization has benefits, such as independence from national political control, but also significant limitations in terms of computational costs and scalability. We introduce RSCoin, a cryptocurrency framework in which central banks maintain complete control over the monetary supply, but rely on a distributed set of authorities, or mintettes, to prevent double-spending. While monetary policy is centralized, RSCoin still provides strong transparency and auditability guarantees. We demonstrate, both theoretically and experimentally, the benefits of a modest degree of centralization, such as the elimination of wasteful hashing and a scalable system for avoiding doublespending attacks.
The article highlights the issues of emergence and existence of cryptocurrency. Exploring online space, you canselect the most popular existing electronic currency which is bitcoin (Bitcoin). The article analyzed the pros andcons and the legality of these
Johannes Göbel, Paul Keeler, A. E. Krzesinski, Peter Taylor
In the context of the `selfish-mine' strategy proposed by Eyal and Sirer, we study the effect of propagation delay on the evolution of the Bitcoin blockchain. First, we use a simplified Markov model that tracks the contrasting states of belief about the blockchain of a small pool of miners and the `rest of the community' to establish that the use of block-hiding strategies, such as selfish-mine, causes the rate of production of orphan blocks to increase. Then we use a spatial Poisson process model to study values of Eyal and Sirer's parameter $γ$, which denotes the proportion of the honest community that mine on a previously-secret block released by the pool in response to the mining of a block by the honest community. Finally, we use discrete-event simulation to study the behaviour of a network of Bitcoin miners, a proportion of which is colluding in using the selfish-mine strategy, under the assumption that there is a propagation delay in the communication of information between miners.
"A New York Times technology and business reporter charts the dramatic rise of Bitcoin and the fascinating personalities who are striving to create a new global money for the Internet age.Digital Gold is New York Times reporter Nathaniel Popper's brilliant and engrossing history of Bitcoin, the landmark digital money and financial technology that has spawned a global social movement.The notion of a new currency, maintained by the computers of users around the world, has been the butt of many jokes, but that has not stopped it from growing into a technology worth billions of dollars, supported by the hordes of followers who have come to view it as the most important new idea since the creation of the Internet. Believers from Beijing to Buenos Aires see the potential for a financial system free from banks and governments. More than just a tech industry fad, Bitcoin has threatened to decentralize some of society's most basic institutions.An unusual tale of group invention, Digital Gold charts the rise of the Bitcoin technology through the eyes of the movement's colorful central characters, including a British anarchist, an Argentinian millionaire, a Chinese entrepreneur, Tyler and Cameron Winklevoss, and Bitcoin's elusive creator, Satoshi Nakamoto. Already, Bitcoin has led to untold riches for some, and prison terms for others.Digital Gold includes 16 pages of black-and-white photos"...
Proces globalizacji i rewolucji informacyjnej to zjawiska, które determinują rzeczywistość społeczno-gospodarczą współczesnego świata. Znalazły one praktyczne odzwierciedlenie w funkcjonowaniu systemów pieniężnych w globalnej gospodarce światowej, przede wszystkim w nowej postaci cyberwaluty, jaką jest bitcoin. Przedmiotem artykułu są przesłanki powstania, istota, zasady i sposób działania bitcoina. Jego cechy oraz coraz szerszy zakres funkcjonowania tej cyberwaluty mogą w przyszłości zagrażać bezpieczeństwu w wymiarze społecznym, gospodarczym i międzynarodowym.
For the past five years, the bitcoin network constantly experience a growth in its size as more communities turn to accept the currency for payment exchanges. Using Flat File and a LevelDB of indices to save blocks on disk, bitcoin users require more memory to save the history of transaction. We focus on issues of memory management and access time in the bitcoin protocol using SQLite DataBase. With all the advantages of SQLite DataBase, it would be efficient if it is fitted in this architecture. The SQLite comes with many flavors one of which is its ability to support sql queries. Thus, instead of parsing indices to search a block from the database, a more powerful query can do the job.
This article is a review of the <i>Handbook of Digital Currency: Bitcoin, Innovation, Financial Instruments, and Big Data</i>, edited by David L.K. Chuen and published by Academic Press. <b>TOPICS:</b>Currency, big data/machine learning
Bitcoin is an innovative virtual currency, which has gained much commercial traction, yet is widely overlooked by the accounting profession. Due to its parallels with actual currencies and its growing use, accountants should be aware of what bitcoin is, including its risks and benefits, in order to properly leverage its business uses. Of the existing financial instruments, derivatives stand out in their potential to stabilize the bitcoin market. Bitcoin regulation is sparse, but evolving, especially in the face of the emerging bitcoin securities and derivatives markets. The accounting profession is poised to play a major role in facilitating the future of proper regulation and oversight of Bitcoin.