Blockchain Papers

Conor Desmond

No abstract is available for this record.

Mihaela Sudacevschi

No abstract is available for this record.

David Golumbia

Bitcoin (BTC), the much in-the-news and up-for-government-discussion cryptocurrency favored by Deep Web drug markets, libertarians, anarchists and would-be assassins everywhere, has been on a tear recently, and as of yesterday has hit an all-time high (albeit briefly) of more than USD $900 mark. It’s not hard to find—in fact it’s difficult to avoid—cyberlibertarians of all...

Jana Drutarovská

Cieľom predkladaného článku je definovať základné podmienky finančnej stability a analyzovať možné hrozby novej experimentálnej virtuálnej meny bitcoin na finančnú stabilitu. Úlohou príspevku je definovať oblasti a faktory, v ktorých táto nová virtuálna mena môže potenciálne spôsobovať finančnú nestabilitu.

Francesc X. Esteban Barbero

No abstract is available for this record.

Marie Pitrová

The main objective of this diploma thesis is to introduce the history and origin of digital currency Bitcoin and how this project works specifically from the perspective of IT. The thesis contains detailed instructions for the process of implementation Bitcoin payments to the company. This diploma thesis describes the possibilities of abuse and security. Further compares advantages and disadvantages with the classical exchange resources. How is it possible to get this currency, use and how it developed its rate against other world currencies. The thesis also mentions similar cryptocurrencies.

Violeta Madzova

A virtual currency can be defined as a type of unregulated, digital money, which is issued and usually controlled by its developers, and used and accepted among the members of a specific virtual community. The recent developments in widely spread internet and data mining activities, highlighted the issue of accepting and using virtual currencies for different purposes, including, buying commodities or services, saving, as well as converting into real currencies, such as US dollars, euro or other currencies. One of the most controversial and the most advanced virtual currency scheme to date is the one so-called Bitcoin, designed and implemented by the Japanese programmer Satoshi Nakamoto in 2009. Although the use of Bitcoin might have positive impact on financial innovation and the provision of additional payment alternatives to consumers, it also might increase the risks in financial payments, exchange rates of real currencies, as well as increase the possibility of money laundering, using them for illegal deeds. Therefore , the purpose of this paper to clarify the main characteristic of Bitcoin, and analyze its positive aspects as well as the threats that may occur to the modern world economy , in case the usage of this money , significantly increases .

Dániel Eszteri

In January 2009 the Japanese software-designer SATOSHI NAKAMOTO invented a virtual currency named Bitcoin and released software for managing transactions in the new money.It consists solely of bits and bytes, but we cannot see it as a coin or banknote on the market.There is no cover in terms of gold or stocks, for example -in fact, nothing but the source code of the software which consists of thirty-one thousand lines of code.NAKAMOTO wanted to create a currency immune to potentially predatory bankers and politicians and so the currency and the mechanism to acquire Bitcoin were controlled entirely by software.The payment system is completely decentralised and so contains no central organisation which monitors transactions.Many people use this new currency to pay for services or products on the Internet, since it is no less safe than traditional payment systems.In this paper I will first introduce the basic parameters and functions of the alternative currency, and will deal especially with security and privacy issues relating to the virtual money.After that I will examine the value of Bitcoin on the online market, especially answering questions such as how we can acquire it.After this the legal background will be presented and suggestions made for its possible regulation, whilst its likely role in criminal behaviour is suggested.The paper was written in order to stimulate interest in this special, new currency, its working mechanisms, advantages and possible dangers, and because it represents a unique paradigm-shift, not simply in cyberspace, but in real-world payment systems also.

Jacob Aron

Aron talks about the virtual currency--Bitcoin. It is a currency founded by revolutionaries that went on to become the worlds dominant payment method. Once little more than the play thing of online libertarians and crypto-anarchists, many Bitcoin advocates are now seeking regulatory and financial legitimacy as an ecosystem of companies springs up to support the currency. In March, the US government sought to actively regulate Bitcoin by requiring companies classified as money transmitters to register with the Financial Crimes Enforcement Network (FinCEN), Mt. Gox, the largest Bitcoin exchange, was founded in 2010 but only registered last month, following the seizure of its accounts in May by the Department of Homeland Security.

Lou Yao-xion

The birth of Bitcoin brings new concept to the currency issuance and circulation.Its characteristics of decentralization and full electronization challenge the current currency system.Theoretically,Bitcoin possesses all the attributes that the currency has,and it will become real legal currency in circulation as long as legal permission.The use of Bitcoin in circulation now will suffer legal issues such as lack of legal status and credit,difficulty in evidence collection and remedy,jurisdiction conflict and so on.The problems mentioned above could only be fundamentally solved if the authority accelerated legislation,established a uniform dispute settlement mechanism,speeded up the establishment of credit system,and enhanced supervision.

Petr Huřťák

Bachelor's thesis is focused on digital currency Bitcoin, mainly on Bitcoin transactions and their attributes like speed, fees and safety. Main goals of this thesis are three, analysis of bitcoin buying possibilities in Czech Republic, comparison of Bitcoin transactions with common payment methods like bank transfers, credit card payment or PayPal, and analysis of number of merchants accepting bitcoin in time and discovery of trend from these data. This thesis is divided into theoretical and practical part. In theoretical part there are described basics of cryptography, which are necessary for understanding Bitcoin, and in depth description how Bitcoin works. Practical part is focused on fulfilment of described goals, besides that thesis is also addressing Bitcoin clients and comparison between most popular ones. Contribution of this bachelor's thesis is analysis of bitcoin buying possibilities in Czech Republic, comparing Bitcoin transactions with transactions of standard payment methods in terms of fees and time, and analysis of trend in number of merchants accepting bitcoin as one of the payment method.

Robert Harm

No abstract is available for this record.

Juan Puig

No abstract is available for this record.

Mihaela SUDACEVSCHI

Bitcoin is a new kind of money, which means a digital currency which can be used for commercial purposes. Over time, the trade has evolved from barter to the use of the precious metals as money, then to the coins with intrinsic value and to the symbol coins and later to the use of the electronic money, reaching at present to a virtual currency, created and used through the internet network. Bitcoin promises to its users getting high returns under conditions of low risk arising from transactions carried out instantly, without intermediary bank and almost no fees. At this moment, Bitcoin is still an experimental new currency, but in the future it can offer an alternative to previous costly systems and it can increase online business access to developing countries.

Petr Huřťák

Bachelor's thesis is focused on digital currency Bitcoin, mainly on Bitcoin transactions and their attributes like speed, fees and safety. Main goals of this thesis are three, analysis of bitcoin buying possibilities in Czech Republic, comparison of Bitcoin transactions with common payment methods like bank transfers, credit card payment or PayPal, and analysis of number of merchants accepting bitcoin in time and discovery of trend from these data. This thesis is divided into theoretical and practical part. In theoretical part there are described basics of cryptography, which are necessary for understanding Bitcoin, and in depth description how Bitcoin works. Practical part is focused on fulfilment of described goals, besides that thesis is also addressing Bitcoin clients and comparison between most popular ones. Contribution of this bachelor's thesis is analysis of bitcoin buying possibilities in Czech Republic, comparing Bitcoin transactions with transactions of standard payment methods in terms of fees and time, and analysis of trend in number of merchants accepting bitcoin as one of the payment method.

Sveinn Valfells

No abstract is available for this record.

Ondřej Jaroš

This bachelor's thesis focuses on the digital currency called Bitcoin. The theoretical part discusses the concept of money (its history, issuance, the gold standard, etc.) as well as central banking and local currencies. It also tackles the concept of Bitcoin itself, the way it functions, its advantages and disadvantages and its issuance (so-called mining). The practical part discusses whether or not it is possible to profit through bitcoin mining, by speculating on its relative value to the (US) dollar and if it is possible for Bitcoin to replace traditional payment systems and currencies in the future (or at least prove itself to be a potent competitor).

Yonatan Sompolinsky, Aviv Zohar

Bitcoin is a potentially disruptive new crypto-currency based on a decentralized opensource protocol which is gradually gaining popularity. Perhaps the most important question that will affect Bitcoin’s success, is whether or not it will be able to scale to support the high volume of transactions required from a global currency system. We investigate the restrictions on the rate of transaction processing in Bitcoin as a function of both the bandwidth available to nodes and the network delay, both of which lower the efficiency of Bitcoin’s transaction processing. The security analysis done by Bitcoin’s creator Satoshi Nakamoto [12] assumes that block propagation delays are negligible compared to the time between blocks—an assumption that does not hold when the protocol is required to process transactions at high rates. We improve upon the original analysis and remove this assumption. Using our results, we are able to give bounds on the number of transactions per second the protocol can handle securely. Building on previously published measurements by Decker and Wattenhofer [5], we show these bounds are currently more restrictive by an order of magnitude than the bandwidth needed to stream all transactions. We additionally show how currently planned improvements to the protocol, namely the use of transaction hashes in blocks (instead of complete transaction records), will dramatically alleviate these restrictions. Finally, we present an easily implementable modification to the way Bitcoin constructs its main data structure, the blockchain, that immensely improves security from attackers, especially when the network operates at high rates. This improvement allows for further increases in the number of transactions processed per second. We show that with our proposed modification, significant speedups can be gained in confirmation time of transactions as well. The block generation rate can be securely increased to more than one block per second – a 600 fold speedup compared to today’s rate, while still allowing the network to processes many transactions per second.

Christina Garman, Matthew Green, Ian Miers

Abstract—Anonymous credentials provide a powerful tool for making assertions about identity while maintaining privacy. However, a limitation of today’s anonymous credential systems is the need for a trusted credential issuer — which is both a single point of failure and a target for compromise. Furthermore, the need for such a trusted issuer can make it challenging to deploy credential systems in practice, particularly in the ad hoc network setting (e.g., anonymous peer-to-peer networks) where no single party can be trusted with this responsibility. In this work we propose a novel anonymous credential scheme that eliminates the need for a trusted credential issuer. Our approach builds on recent results in the area of electronic cash that, given a public append-only ledger, do not need a trusted credential issuer. Furthermore, given a distributed public ledger, as in, e.g., Bitcoin, our system requires no credential issuer at all and hence is decentralized. Using such a public ledger and standard cryptographic primitives, we propose and provide a proof of security for a basic anonymous credential system that allows users to make flexible identity assertions with strong privacy guarantees without relying on trusted parties. Finally, we discuss a number of practical applications for our techniques, including resource management in ad hoc networks and prevention of Sybil attacks. We implement our scheme and measure its efficiency. I.

Michał Polasik, Anna Piotrowska, Radosław Kotkowski

Praca dotyczy sposobow wykorzystania waluty wirtualnej Bitcoin w handlu elektronicznym oraz przyjmowaniu darowizn przez organizacje non-profit. Jej celem jest określenie charakterystyki legalnych akceptantow Bitcoin, ustalenie metod akceptowania tej waluty oraz jej udzialu w ogolnej wartości sprzedazy. Wyniki empiryczne zostaly oparte na przeprowadzonym badaniu ankietowym, w ktorym wzielo udzial 111 oferentow internetowych z 35 krajow. Badanie umozliwilo określenie zasiegu akceptacji Bitcoin, jak rowniez poznanie profilu przyjmujących ją firm, z uwzglednieniem takich czynnikow, jak: profil dzialalności, lokalizacja, branza, zasieg geograficzny oraz skala prowadzonej dzialalności. Uzyskane wyniki wykazaly ponadto, ze w procesie akceptacji tej waluty bardzo istotną role odgrywają integratorzy platności. Jednocześnie obserwowane jest wśrod klientow niewielkie zainteresowanie platnością z uzyciem Bitcoin. (abstrakt oryginalny)

Wojciech Nowakowski

No abstract is available for this record.

Ying Zhang

Recently,more and more people are quite attracted to a new digital currency which is called Bitcoin because of its anonymity,non-central authority,limited total amount,low transaction cost and free? convertibility.However,it could cause problems or risk of speculation,cyber crime,the waste of resource,the huge fluctuation in the price and so on.The emergence of Bitcoin is attributed to technical,economic and social factors.So rather than in just one aspect,Bitcoin should be concerned in different aspects,such as research,education and governance.

Wen Xiaozhen

Bitcoin in its currency essence and at the technical level can be used to build a safe,reliable decentration payment system so that the problems in electronic money with multiple payment bills can be solved.From the analysis of the application level,the bitcoin has shortage in trust,illegal trading,deflation,and decentration.Considering the influence of bitcoin on the current financial system and the implications for future development,researches on bitcoin should be strengthened by the research institutions and the International Monetary Fund.The currency theory and application of bitcoin should be explored further.Governments and central banks should face the scientific and revolutionary of bitcoin.Technical departments and legislative bodies should strengthen researches and legislation supervision of bitcoin,and solve the problem of the initial allocation of currency.

Ghassan Karame, Arthur Gervais, Hubert Ritzdorf

In this article, we discuss a possible exploit in Bitcoin that arises from the simultaneous adoption of client versions 0.8.1 and 0.8.2 (or 0.8.3) in the network. In version 0.8.2, Bitcoin clients no longer accept transactions with non-strict signature encoding. As we show, this incompatibility with prior client versions can potentially lead to a double-spending attack in a fast payment setting in Bitcoin. The attack can only work when merchants operate on any client version prior to 0.8.2. Our aim is therefore to raise the awareness of merchants to adopt version 0.8.2 (or 0.8.3) if they are willing to accept fast payments [1].