Blockchain Papers

Park Jong Hyun, 유승민

No abstract is available for this record.

Joseph Bonneau, Andrew Miller, Jeremy Clark, Arvind Narayanan · 6 authors

Bit coin has emerged as the most successful cryptographic currency in history. Within two years of its quiet launch in 2009, Bit coin grew to comprise billions of dollars of economic value despite only cursory analysis of the system's design. Since then a growing literature has identified hidden-but-important properties of the system, discovered attacks, proposed promising alternatives, and singled out difficult future challenges. Meanwhile a large and vibrant open-source community has proposed and deployed numerous modifications and extensions. We provide the first systematic exposition Bit coin and the many related crypto currencies or 'altcoins.' Drawing from a scattered body of knowledge, we identify three key components of Bit coin's design that can be decoupled. This enables a more insightful analysis of Bit coin's properties and future stability. We map the design space for numerous proposed modifications, providing comparative analyses for alternative consensus mechanisms, currency allocation mechanisms, computational puzzles, and key management tools. We survey anonymity issues in Bit coin and provide an evaluation framework for analyzing a variety of privacy-enhancing proposals. Finally we provide new insights on what we term disinter mediation protocols, which absolve the need for trusted intermediaries in an interesting set of applications. We identify three general disinter mediation strategies and provide a detailed comparison.

Muhammad T. Alam, Haozhang Li, Abhishek Patidar

The editorial board announced this article has been retracted on July 19, 2016. If you have any further question, please contact us at: cis@ccsenet.org

Thomas Kim

To examine whether the recent price patterns and transaction costs of Bitcoin represent a general characteristic of decentralized virtual currencies, we analyze virtual currencies in online games that have been voluntarily managed by individuals since 1990s. We find that matured game currencies have price stability similar to that of small size equities or gold, and their transaction costs are sometimes lower than real currencies. Assuming that virtual currencies with a longer history can provide an estimate for Bitcoin's prospects, we project that Bitcoin will be less influenced by speculative trades and become a low cost alternative to real currencies.

Jan A. Bergstra

For money-like informational commodities the notions of architectural adequacy and evolutionary adequacy are proposed as the first two stages of a moneyness maturity hierarchy. Then three classes of informational commodities are distinguished: exclusively informational commodities, strictly informational commodities, and ownable informational commodities. For each class money-like instances of that commodity class, as well as monies of that class may exist. With the help of these classifications and making use of previous assessments of Bitcoin, it is argued that at this stage Bitcoin is unlikely ever to evolve into a money. Assessing the evolutionary adequacy of Bitcoin is perceived in terms of a search through its design hull for superior design alternatives. An extensive comparison is made between the search for superior design alternatives to Bitcoin and the search for design alternatives to a specific and unconventional view on the definition of fractions.

Susana Navas Navarro

El Bitcoin (BTC) va apareciendo regularmente en los medios de comunicacion por diversos motivos. Desde la quiebra de una conocida casa de cambios en Estados Unidos (Mt. Gox) hasta la constitucion de una sociedad cuyo capital social esta denominado exclusivamente en esta criptomoneda pasando por el anuncio de que algunas tiendas de la Milla de oro de Madrid acepten como medio de pago la moneda virtual no regulado de la que trata este trabajo. Nosotros nos proponemos estudiar, desde el Derecho privado, la configuracion juridica del BTC planteando cuestiones e intentando resolverlas. La conclusion a la que llegamos es que es una moneda virtual que funciona, hoy por hoy, de forma similar a una divisa y que el legislador deberia limitar su intervencion, el dia en que asi lo decida, a permitir su conversion a la moneda fiduciaria de uso legal.

Erwan Jonchères

Les cryptomonnaies sont des monnaies numériques, qui se sont développées hors de tout contrôle étatique et qui fonctionnent de manière décentralisée. Bien qu’étant encore à leurs balbutiements, ces cryptomonnaies, à l’instar du Bitcoin, soulèvent de nombreuses questions juridiques. Dans ce mémoire, seront analysées les différentes définitions qui pourraient inclure la cryptomonnaie, avant de nous concentrer sur la définition de la monnaie numérique. Ensuite, seront étudiés, les aspects criminogènes des cryptomonnaies et la volonté des États d’avoir un certain contrôle sur celles-ci. Puis après nous être concentré sur la fiscalité applicable aux monnaies numériques, il sera nécessaire d’examiner l’étendue de la protection des consommateurs, dans leurs rapports aux cryptomonnaies. Pour ce faire nous nous appuierons, entre autre, sur les lois canadiennes, françaises et américaines. Toutefois vous vous en rendrez-compte, les cryptomonnaies n’ont pas encore été totalement englobés dans les systèmes juridiques des trois pays étudiés, et les tribunaux n’ont été saisis que dans très peu d’affaires relatives aux monnaies numériques, ce qui implique que de nombreuses incertitudes juridiques persistent à l’heure actuelle.

Simon Trimborn

In dieser Thesis wird ein Marktindex konstruiert, wobei neu entwickelte Methoden für solch eine Aufgabe verwendet werden. Die Entscheidung über die Anzahl der Indexteilnehmer wird mithilfe des AIC und BIC Kriteriums getroffen und die Liquiditätsregel wird auf Grundlage der BIS Umfrage ermittelt. Dieser neu entwickelte Index, CRIX, wird dann benutzt, um den Kryptowährungsmarkt gegen Bitcoins und andere Märkte zu vergleichen. Es wurde herausgefunden, dass dieser Markt wesentlich risikoreicher ist als andere Märkte. Es wird außerdem ein Minimum Varianz CRIX und ein optimales Vorhersagemodel für den Index entwickelt, wobei Daten aus sozialen Netzwerken verwendet werden.

Nicholas J. Ajello

No abstract is available for this record.

Béla Gipp, Norman Meuschke, André Gernandt

Trusted timestamping is a process for proving that certain information existed at a given point in time. This paper presents a trusted timestamping concept and its implementation in form of a web-based service that uses the decentralized Bitcoin block chain to store anonymous, tamper-proof timestamps for digital content. The service allows users to hash files, such as text, photos or videos, and store the created hashes in the Bitcoin block chain. Users can then retrieve and verify the timestamps that have been committed to the block chain. The non-commercial service enables anyone, e.g., researchers, authors, journalists, students, or artists, to prove that they were in possession of certain information at a given point in time. Common use cases include proving that a contract has been signed, a photo taken, a video recorded, or a task completed prior to a certain date. All procedures maintain complete privacy of the user's data.

Morten Brandvold, Péter Molnár, Kristian Vagstad, Ole Christian Andreas Valstad

No abstract is available for this record.

Ferdinando M. Ametrano

Bitcoin extreme deflationary price instability has hampered its usability, making it impractical for spot transactions and unserviceable for deferred payments. Ametrano (2014) has proposed as Hayek Money a cryptocurrency price stability paradigm of elastic non-discretionary monetary policy. An implementation using a dual asset ledger for stable coins and seigniorage shares is presented here. A DeCentralized Reserve Bank (as Decentralized Autonomous Organization) is introduced as active market agent using bitcoin as reserve asset to preserve price parity. The socially inefficient over-investment of seigniorage revenues in transaction verification can be avoided using proof-of-payment.This schema frees coins from any speculative value, thus favoring money velocity and increasing the number of transactions. Seigniorage shares are effectively to be considered as a participation in a distributed central bank: as such the owners are entitled to seigniorage revenues in exchange for being subjected to the losses associated to coin price stability defense, obliged to validation task duties, and in charge of price index observation.

Ashley S. Harrison, M. Scott Niederjohn, J. R. Clark

Economists define money as anything that is generally accepted in payment for goods and services or in the repayment of debts.1 Paper money and coins clearly fit this definition, but deposits in checking accounts are so widely accepted that they are also considered in the narrowest definition of money used by the Federal Reserve, called “M1.” M1 is the sum of all currency, checkable deposits, and travelers checks. How about savings accounts? These amounts are so quickly convertible into M1 that many economists consider them money too, part of a larger total called M2 that includes all of M1 plus all small denomination time deposits (bank CDs), savings accounts, and money market account balances. M2 then represents a form of money that is less “liquid” (less easily converted and spent) than M1. In addition to this definition, money is expected to satisfy three functions: serve as a medium of exchange, a store of value, and a unit of account. In this article, we will explore what Bitcoin is and why it has been so prevalent in the news of late. Further, we will apply the three functions of money to Bitcoin and discuss whether it should be considered a form of money. Some of the benefits and problems associated with Bitcoin will be discussed along with its future potential.

K. Down, Martin Hutchinson

Bitcoin is most radical innovation in monetary space for a very long time. It is an entirely private monetary system that runs itself and does not depend on trust in any central authority to honor its promises. Instead, it relies on trust in Bitcoin community or network that verifies transactions and maintains integrity of system. This system of distributed trust creates bitcoins and produces an automatic, tamper-proof bitcoin money supply process. (1) As such, it avoids dangers of discretionary monetary policy--namely, quantitative easing, manipulated interest rates, and need to rely on wise men or women to withstand political pressure or successfully forecast future. Indeed, under Bitcoin there is no monetary policy at all. There is just an automatic monetary rule dictated by Bitcoin protocol designed in 2009 by an anonymous programmer using alias Satoshi Nakamoto. Bitcoin has been widely hailed as a success and has won a substantial following. Unfortunately, underlying economics of Bitcoin mean that it is unsustainable and in all likelihood will be remembered as a failed experiment--at best a pointer to some superior successor. A first-pass intuition into Bitcoin can be obtained from a comparison with stone money in Milton Friedman's (1992) case study, Island of Stone Money. In this story, people of island of Yap in Micronesia used as money large round limestone disks transported from nearby island of Palau. These were too heavy to conveniently move around, so they were placed in prominent places. When ownership was to be transferred (e.g., as part of a dowry, inheritance, or ransom payment), current owner would publicly announce change in ownership but stone would typically remain where it was and islanders would maintain a collective memory of ownership history of stones. This collective memory ensured that there was no dispute over who owned which stones. Similarly, in Bitcoin, record of all transactions, blockchain, is also public knowledge and is regarded as die definitive record of who owns which bitcoins. Both stone money and Bitcoin share a critical feature that is highly unusual for a monetary system: both systems operate via a decentralized collective memory. On February 11, 2009, Nakamoto gave an explanation of thinking behind Bitcoin in an e-mail announcing its launch: root problem with conventional currency is all trust that is required to make it work. The central bank must be trusted not to debase currency, but history of fiat currencies is full of breaches of that trust.... With e-currency based on cryptographic proof, without die need to trust a third-party middleman, money can be secure and transactions complete. Cryptocurrencies, however, face problem of As Nakamoto notes, owner could try to re-spend an already spent coin by [digitally] signing it again to another owner. The usual solution is for a trusted company with a central database to check for double-spending, but that just gets back to trust model.... Bitcoin's solution is to use a peer-to-peer network to check for double-spending. Consequently, the result is a distributed system with no single point of failure. (2) Kevin Dowd is Professor of Finance and Economics at Durham University in United Kingdom and a partner at Cobden Partners. Martin Hutchinson is a journalist and author of Bear's Lair column (www.tbwns.com/category/the-bears-lair). The authors thank Ferdinando Ametrano, Gavin Andresen, Raadhiyah Anees, Steve Baker MP, Roger Brown, Dave Campbell, Akin Fernandez, Dominic Frisby, Jim Harper, Doug Jackson, Gordon Kerr, Jim Rapp, Eric Samieski, Lawrence H. White and Basil Zafiriou for much helpful feedback. We note that several of our readers have expressed serious reservations about our analysis and conclusions. Any remaining mistakes are authors' own. …

Zoran Čekerevac, Zdeněk Dvořák, Ludmila Prigoda, Petar Čekerevac

Bitcoin, digital money got into focus after the Mt Gox crash. It uses P2P interaction where an owner transfers the electronic coin to the next owner signing and adding a hash of the previous transaction and the public key of the next owner. Payment verification is accomplished by notifying the entire network about the transaction. This prevents double-spending and generation of non-existent money. Among the users, there is uncertainty about the safety on the theft and fraud. Among the authorities, there are dilemmas about present and future risks related to the Bitcoin implementation. The article deals with the benefits and risks of Bitcoin use.

Jeremy Eng‐Tuck Cheah, John Fry

No abstract is available for this record.

Benjamin W. Akins, Jennifer Chapman, Jason M. Gordon

A Whole New World: Income Tax Considerations of the Bitcoin Economy

Béla Gipp, Norman Meuschke, André Gernandt

Trusted timestamping is a process for proving that certain information existed at a given point in time. This paper presents a trusted timestamping concept and its implementation in form of a web-based service that uses the decentralized Bitcoin block chain to store anonymous, tamper-proof timestamps for digital content. The service allows users to hash files, such as text, photos or videos, and store the created hashes in the Bitcoin block chain. Users can then retrieve and verify the timestamps that have been committed to the block chain. The non-commercial service enables anyone, e.g., researchers, authors, journalists, students, or artists, to prove that they were in possession of certain information at a given point in time. Common use cases include proving that a contract has been signed, a photo taken, a video recorded, or a task completed prior to a certain date. All procedures maintain complete privacy of the user's data.

Jeremy Papp

Banks and other financial institutions have evolved along with e-commerce by enabling unfamiliar parties to transact around the globe with little to no risk. This service does not come without a price. Bitcoin was established as a more efficient way to securely transact online, removing the need for third-party financial institutions. The purpose of this Note is to highlight the potential of Bitcoin as a medium of exchange, making Internet transactions more flexible and affordable to all. The author analyzes Bitcoin’s current price volatility, highlighting a trend of Bitcoin-backed investments, and argues against any government action in support of these purely speculative and short-sited investment schemes. This Note expounds upon the major obstacles facing Bitcoin’s acceptance by mainstream commercial marketplaces. Most importantly, the author looks at future government intervention, and argues against any direct legislation on the Bitcoin system in order to allow for its growth and development.

Juan José García Chávez, Carlo Kleber da Silva Rodrigues

No abstract is available for this record.

Juan Eduardo Pazmiño, Carlo Kleber da Silva Rodrigues

No abstract is available for this record.

Davide Carboni

The ability to assess the reputation of a member in a web community is a need addressed in many different ways according to the many different stages in which the nature of communities has evolved over time. In the case of reputation of goods/services suppliers, the solutions available to prevent the feedback abuse are generally reliable but centralized under the control of few big Internet companies. In this paper we show how a decentralized and distributed feedback management system can be built on top of the Bitcoin blockchain

Michael Fleder, Michael S. Kester, Sudeep Pillai

Bitcoins have recently become an increasingly popular cryptocurrency through which users trade electronically and more anonymously than via traditional electronic transfers. Bitcoin's design keeps all transactions in a public ledger. The sender and receiver for each transaction are identified only by cryptographic public-key ids. This leads to a common misconception that it inherently provides anonymous use. While Bitcoin's presumed anonymity offers new avenues for commerce, several recent studies raise user-privacy concerns. We explore the level of anonymity in the Bitcoin system. Our approach is two-fold: (i) We annotate the public transaction graph by linking bitcoin public keys to "real" people - either definitively or statistically. (ii) We run the annotated graph through our graph-analysis framework to find and summarize activity of both known and unknown users.

정승영

No abstract is available for this record.