Blockchain Papers

Robby Houben

No abstract is available for this record.

Armağan Ebru Bozkurt Yüksel

OZ Internet [1] hayatin her alanini etkilemektedir. Gun gectikce Internet’e bagla­nan kisilerin sayisi artmaktadir. Pek cok alanda yararlanilan Internet’ten ticarette de yararlanilmaktadir. Internet’te herhangi bir calisma saati veya is­yeri ile siniri olmaksizin gerceklesen ticaret, isletmelerin giderek daha fazla ilgisini cekmektedir [2] . Elektronik ticaretin [3] yukselisi ve teknolojideki ilerlemeler yeni odeme sistemlerinin kullanimini baslatmistir. Bu makalede elektronik odeme yontemleri genel olarak degerlendirdikten sonra elektronik paranin bir cesidi olan sanal paranin en bilinen orneklerini olusturan Bitcoin ve Linden Dolari incelenmektedir. Calismada elektronik paranin avantaj ve dezavantajlari ve konu ile ilgili oneriler dunyadaki ve Turkiye’deki uygulamalar gozonunde tutularak degerlendirilmistir. Anahtar Kelimeler: Elektronik Para, Sanal Para, Kripto Para, Bitcoin, Linden Dollars ABSTRACT Internet affects all areas of life. The number of persons who connects to the Internet increases day by day. It has been benefited from the Internet in numerous fields and in commerce as well. The commerce which takes place on the Internet without any burdens of working hours or workplaces attracts the business concerns increasingly. The rise of electronic commerce and the developments in technology have started the use of new payment systems. This article attempts to assess the electronic payment methods generally and then analyse the best known virtual currencies Bitcoin and Linden Dollars which are also types of electronic money. In this work the advantages and the disadvantages of electronic money and the suggestions about the subject has been evaluated by looking at the practice in the world and in Turkey. Keywords: Electronic Money, Virtual Currency, Crypto Currency, Bitcoin, Linden Dollars [1] Bu calismada Internet kelimesinin ilk harfi ozel isim olmasi nedeni ile buyuk yazilmis­tir. Internet, birbirine bagli bilgisayar aglari kelimelerinin (Interconnection of computer networks) kisaltmasidir. http://www.Internetnedir.net/Internet-nedir-ne-degildir.html (Erisim: 22.03.2014); Turk Dil Kurumu, Internet kelimesinin karsiligi olarak genel ag demektedir. http://tdk.gov.tr/index.php?option=com_gtsa Oyle ki, elektronik ticaret Amerika Birlesik Devletleri’nde her yil %20 buyuyen 220 Milyar Amerikan Dolarlik bir endustri haline gelmistir. 2017 yilinda bu rakamin 270 Milyar Amerikan Dolari’na cikmasi beklen­mektedir. Avrupa’da ise elektronik ticaretin her yil buyume orani %11’dir.; Morrison, K.: The Growth of E-commerce, http://socialtimes.com/data-growth-e-commerce-infographic_b198687 (Erisim 31.08.23014); Turkiye’de 2009 yilindan 2013 yilina kadar olan donemde elektronik ticarette buyume orani % 379,91’dir. 2013 yili itibari ile elekt­ronik ticaret 35 Milyar Turk Lirasina yakin islem hacmine ulasmistir. Yillara gore elektronik ticaretin gelisim oranlari ve detayli bilgi icin bkz. http://www. platinmarket.com/2009-2013-arasi-turkiye-e-ticaret-buyume-orani/ (Eri­sim 30.10.2014). [3] 6563 sayili Elektronik Ticaretin Duzenlenmesi Hakkinda Kanun’un 1(a) maddesinde elektronik ticaret “fiziki olarak karsi karsiya gelmeksizin elektronik ortamda gerceklesti­rilen cevrimici iktisadi ve ticari her turlu faaliyet” olarak tanimlanmistir. Elektronik tica­retin doktrinde degisik tanimlari bulunmaktadir. “Elektronik ticaret, yazi, ses ve/veya goruntu seklindeki verilerin elektronik ortamda islenmesi ve iletilmesi suretiyle gercekles­tirilen ticari islemlerin butunudur.” seklindeki tanim icin bkz. Ozdemir Kocasakal, H.: Elektronik Sozlesmelerden Dogan Uyusmazliklarin Cozumunde Uygulanacak Hukukun ve Yetkili Mahkemelerin Tespiti, Vedat Kitapcilik, Istanbul 2003, s.5; Dar anlamda elektronik ticaretin Internet uzerinden ve bilgisayar vasitasi ile gerceklestirilen ticari faaliyetleri ifade ettigi seklinde tanim icin bkz. Kayihan, S. / Yildiz, H.: Elektronik Tica­retin Hukuki ve Vergi Boyutu, Seckin Yayinevi, Ankara 2004, s.39; Elektronik ticaretin ticari islemlerin tamaminin veya bir kisminin elektronik iletisim araclari araciligiyla gerceklestirilmesi seklinde tanimi icin bkz. Sariakcali, T.: Internet Uzerinden Akdedilen Sozlesmeler, Seckin Yayinevi, Ankara 2008, s.19.

Martina E. Greiner, Hui Wang

Trust has always been important in electronic commerce. Prior research in MIS has mainly focused on trust-building mechanisms and insurance against opportunistic behavior. We suggest a “trust-free system” approach, which addresses trust issues by eliminating the need for trust. Using Bitcoin, a decentralized electronic cash system, we illustrate how a system can solve trust issues by becoming “trust-free” through design. We discuss the design features of this approach, and explore research questions for generalizing the design to other information systems. The idea of a trust-free system opens a new way of thinking about trust issues in information systems. We believe that there is an untapped potential for new ideas and research on how to design and evaluate information systems.

Алексей Чурилов

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.

J Wonglimpiyarat

This paper is concerned with the new Darwinism of the payment system. The researcher discusses the payment system to understand if Bitcoin would replace our cash-based society. The analysis is based on the technology S-curve and Schumpeter’s model of economic development. At present, there are problems hindering Bitcoin innovation to achieve a wide adoption as the innovation is not well received by the government central banks around the world. It is interesting to see that the swing of S-curves is not strong enough to cause a paradigm shift according to the Schumpeterian concept of creative destruction. The results have shown parallel S-curve trajectories of electronic money innovations signifying a move from a cash-based economy towards a less cash society. The study provides useful implications to support the diffusion of Bitcoin innovation.

Loi Luu, Viswesh Narayanan, Kunal Baweja, Chaodong Zheng · 6 authors

Abstract—In this paper, we design a new blockchain Byzantine consensus protocol SCP where the throughput scales nearly lin-early with the computation: the more computing power available, the more blocks selected per unit time. SCP is also efficient that the number of messages it requires is nearly linear in the network size. The computational scalability property offers the flexibility to tune bandwidth consumption by adjusting computational param-eters (e.g., proof-of-work difficulty). The key ideas lie in securely establishing identities for network participants, randomly placing them in several committees and running a classical consensus protocol within each committee to propose blocks in parallel. We further design a mechanism to allow reaching consensus on blocks without broadcasting actual block data, while still enabling efficient block verification. We prove that our protocol is secure, efficient and applicable to several case studies. We conduct scalability experiments on Amazon EC2 with upto 80 cores, and confirm that SCP matches its theoretical scaling properties. I.

Dominique Unruh

We present a new definition of computationally binding commitment schemes in the quantum setting, which we call “collapse-binding”. The definition applies to string commitments, composes in parallel, and works well with rewindingbased proofs. We give simple constructions of collapse-binding commitments in the random oracle model, giving evidence that they can be realized from hash functions like SHA-3. We evidence the usefulness of our definition by constructing three-round statistical zero-knowledge quantum arguments of knowledge for all NP languages.

Ramesh Subramanian, Theo Chino

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.

Syed Taha Ali

No abstract is available for this record.

Nicolas T. Courtois, Pinar Emirdag, Zhouyixing Wang

In this paper we study the question of centralisation in bitcoin digital currency. In theory bitcoin has been designed to be a totally decentralized distributed system. Satoshi Nakamoto has very clearly postulated that each node should be collecting recent transactions and trying to create new blocks (Satoshi08). In bitcoin transactions are aggregated in block in order to authenticate them and form an official ledger and history of bitcoin transactions. In practice as soon as expensive ASIC bitcoin miners have replaced general-purpose hardware, production of bitcoins and the validation of transactions has concentrated in the hands of a smaller group of people. Then at some moment in early 2012 an important decision was taken: the Stratum protocol was designed (Palatinus12) which took a deliberate decision to move the power of selecting which transactions are included in blocks from miners to pool managers. The growing difficulty of mining and large standard deviation in this process (Rosenfeld13; CourtoisBahack14) made that majority of miners naturally shifted to pooled mining. At this moment bitcoin ceased being a decentralized democratic system. In this paper we survey the question of a 51% attacks and show that there is a large variety of plausible attack scenarios. In particular we study one particularly subversive attack scenario which depends on non-trivial internal details of the bitcoin hashing process. How does it compare with the current mining practices? We have study the Stratum protocol in four popular real-life mining configurations. Our analysis shows that pools could very easily cheat the majority of people. However the most subversive versions of the attack are NOT facilitated and could potentially be detected.

Yoad Lewenberg, Yonatan Sompolinsky, Aviv Zohar

No abstract is available for this record.

Filipe Drebes Scarinci

Os mais diversos sistemas monetários foram experimentados pela socidade até chegarmos no modelo atual e há poucos indícios de que este deva ser o último e definitivo. Existe uma insatisfação com o sistema vigente e com o grande poder que as autoridades monetárias adquiriram nos últimos anos. Novos modelos vêm surgindo nas mais diversas áreas, e uma das alternativas que se desenha para o arranjo financeiro é o Bitcoin, um sistema monetário completamente descentralizado, que se utiliza da tecnologia pessoa-a-pessoa para transformar o modo como os indivíduos se relacionam. O trabalho se propõe a analisar a origem, as características, o funcionamento e as inovações trazidas pelo sistema Bitcoin, comparando a criptomoeda às outras moedas tradicionais estudadas na literatura econômica. Em especial, trata de analisar a factibilidade do Bitcoin enquanto moeda.

Yunyoung Hur, Seongmin Jeon, Byungjoon Yoo

Ever since its creation by the presumed pseudonymous Satoshi Nakamoto, Bitcoin has garnered significant attention as an innovative online payment system. The purpose of this paper is to discover the degree to which the participation of a Bitcoin user is dependent on the speculative opportunities in the Bitcoin market and, accordingly, to test Bitcoin’s competence against traditional currency. Using a panel data set from one of the largest Bitcoin traders in Asia, we find that $1 increase in arbitrage between market prices is associated with 0.1 more log-ins of users. However, the paper also suggests that such a speculative nature might not be strong enough to dominate user behaviors entirely. The findings report that the actual reason for Bitcoin’s incompetence as a form of currency against the conventional tools of trade may be attributable to its low level of network effects.

Gaby G. Dagher, Benedikt Bünz, Joseph Bonneau, Jeremy Clark · 5 authors

Bitcoin exchanges function like banks, securely holding their cus-tomers ’ bitcoins on their behalf. Several exchanges have suffered catastrophic losses with customers permanently losing their sav-ings. A proof of solvency demonstrates that the exchange controls sufficient reserves to settle each customer’s account. We introduce Provisions, a privacy-preserving proof of solvency whereby an ex-change does not have to disclose its Bitcoin addresses; total hold-ings or liabilities; or any information about its customers. We also propose an extension which prevents exchanges from colluding to cover for each other’s losses. We have implemented Provisions and it offers practical computation times and proof sizes even for a large Bitcoin exchange with millions of customers.

Ignacio Más, David Lee Kuo Chuen

No abstract is available for this record.

Benedikt C. Eikmanns, Philipp Sandner

Despite a high volatility and the recent fall in price, more and more merchants and consumers adopt Bitcoin. The virtual currency might be standing at its critical point to reach the early majority of adopters. This paper examines whether an application called ChangeTip has the potential to catalyze the breakthrough of Bitcoin. We assume a strong linkage between the diffusion of ChangeTip and Bitcoin so that we can directly deduce the impact of this application on Bitcoin. Results from a conducted online survey of 210 potential early adopters indicate that the diffusion of ChangeTip has the potential to advance the diffusion of Bitcoin to mainstream markets. We found that performance expectancy is the key driver for the intention to recommend ChangeTip. Also, effort expectancy, social influence and facilitating conditions are important factors for recommending ChangeTip. Concerning the intention to use ChangeTip in the future, performance expectancy and social influence are the main drivers. Furthermore, facilitating conditions are important for using ChangeTip. In addition, an analysis of the non-user of Bitcoin and ChangeTip was conducted. Theoretical and practical implications of these results are discussed.

Liam Morris

Cash in the real world allows for parties to exchange currency without the need to go through some sort of central authority. One person, Alice, can simply hand cash over to another person, Bob. In this transaction the only two people that have knowledge of this exchange are Alice and Bob. Until recently there was no electronic equivalent to this exchange. In 1982 David Chaum proposed a system of anonymous electronic cash based on blind signatures, and in 1990 founded DigiCash as an electronic cash company. There were a few banks that implemented electronic cash systems, but these banks and DigiCash ultimately went bankrupt in 1997 and 1998 despite the enthusiasm surrounding anonymous electronic cash. Between 1998 and 2008 there were no successful implementations of electronic cash that offer a decentralized, anonymous, and untraceable system.\nIn 2008 a paper was published by Satoshi Nakamoto on the cryptocurrency known as Bitcoin. A cryptocurrency is a form of electronic cash backed by mathematical and cryptographic constructs, unlike traditional currency which was historically backed by gold or silver. Cryptocurrencies have seen rising popularity in recent years due to their decentralized, distributed, peer-to-peer protocols. Part of this rising popularity is also attributable to the supposed anonymity of these protocols; however, due to the public transaction history required for these protocols and the fact that transactions are pseudonymous and not purely anonymous, this supposed anonymity does not exist. While the systems may achieve the goal of decentralized currency it does not achieve the goal of untraceability. In this thesis we analyze the technical implementations of Bitcoin and other cryptocurrencies to determine the level of anonymity provided by these protocols. We also analyze proposed improvements for their feasibility.

J.A. Bergstra

Six assertions concerning the status of Bitcoin are formulated and defended: (i) Bitcoin is not and will not become a currency-like informational commodity, (ii) currency-like informational commodities that aren’t currencies must be frauds, (ii) specific BTC amounts may become monetized and thus may be turned into financial assets, (iii) currently no BTC amounts are monetized in any currency area and therefore none are financial assets, (iv) by means of burocratic steps only some BTC volumes can be turned in to an informational currency within a given currency area, modified client software is not required for that step, (v) if a specific amount of BTC qualifies as currency, it also qualifies as money, (vi) moneyness of Bitcoin, or rather of a specific occurrence of an amount of BTC, should be questioned only after one has agreed positively on its status as a financial asset, and negatively on its status as an amount of currency. Factions in the Bitcoin promoting movement are viewed from a perspective of organizational multi-threading. Different factions of the Bitcoin movement may wish to see status issues about Bitcoin settled in different ways. Overall consistency in these matters should not be expected from the union of factions in the Bitcoin movement.

Pasquale Forte, Diego Romano, Giovanni Schmid

After more than six years from the launch of Bitcoin, it has become ev-ident that the decentralized transaction ledger functionality implemented through the blockchain technology can be used not only for cryptocur-rencies, but to register, confirm and transfer any kind of contract and property. In this work we analyze the most relevant functionalities and known issues of this technology, with the intent of pointing out the pos-sible behaviours that are not as efficient as they should when thinking with a broader outlook. Our analysis would be the starting point for the introduction of a new approach to blockchain creation and management, which will be the subject of a forthcoming paper. 1

Nirupama Devi Bhaskar, Lam Pak Nian, David Lee Kuo Chuen

No abstract is available for this record.

Hanna Hałaburda, Miklós Sárváry

No abstract is available for this record.

Ralph McKinney, Lawrence P. Shao, Duane C. Rosenlieb, Dale H. Shao

No abstract is available for this record.

Daniel Folkinshteyn, Mark M. Lennon

Bitcoin is widely represented in the popular press, but far less so in serious academic inquiry. Researchers have analyzed Bitcoin from various discipline-specific perspectives using their own sets of theories and jargon. Yet cross-disciplinary research has been muddled by the inaccurate interpretation of terminology across fields of research. This results in polarized assessments. In an effort to examine the Bitcoin phenomenon in a more holistic and multidisciplinary manner, this paper compares Bitcoin with another innovative technology – the World Wide Web – as first envisioned by Tim Berners-Lee. By exploring the early development of the World Wide Web, we seek to compare and contrast its development with that of Bitcoin and blockchain technology. The goal of this study is to show similarities and differences in their historic development, in order to identify key success factors related to the adoption of these technologies. Through identification of these factors we seek to guide both academics and practitioners towards fruitful avenues of research and development.

Jia Liu, Saqib A. Kakvi, Bogdan Warinschi

No abstract is available for this record.