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94,395 results ¡ page 3593 of 3,934
Aggelos Kiayias, Ioannis Konstantinou, Alexander Russell, Bernardo David ¡ 5 authors
No abstract is available for this record.
Iddo Bentov, Rafael Pass, Elaine Shi
No abstract is available for this record.
Jack Pettersson, Robert EdstrĂśm
We show how dependent and polymorphic types can make smart contract development safer. This is demonstrated by using the functional language Idris to describe smart contracts on the Ethereum platform. In particular, we show how one class of common errors can be captured at compile time using dependent types and algebraic side effects. We also bring type annotations to the realm of smart contracts, helping developers to circumvent another class of common errors. To demonstrate the feasibility of our solutions, we have extended the Idris compiler with a backend for the Ethereum Virtual Machine. While we find that the functional paradigm might not be the most suitable for the domain, our approach solves the identified problems and provides advantages over the languages in current use.
Marie Larsson Linton, Ernie G. S. Teo, Elisabeth Bommes, ChengâYing Chen ¡ 5 authors
No abstract is available for this record.
WacĹaw Banasik, Stefan Dziembowski, Daniel Malinowski
No abstract is available for this record.
Masooda Bashir, B.R. Strickland, Jeremiah Bohr
No abstract is available for this record.
Rachid El Bansarkhani, Jan Egbert Sturm
No abstract is available for this record.
Ilias Giechaskiel, Cas Cremers, Kasper Rasmussen
No abstract is available for this record.
Junpeng Wang, Xue Yubo, Minghao Liu
As the world's first completely decentralized digital payment system, the emergence of bitcoin represents a revolutionary phenomenon in financial markets. This paper mainly studies the fluctuations of bitcoin price and discusses weather digital currencies represented by bitcoin have the potential to invest. Cointegration analysis and VEC (Vector Error Correction) Model have been performed to demonstrate the relationship between bitcoin price and some variables including stock price index, oil price and daily trading volume of bitcoin. The empirical research indicates that there is long-term equilibrium and short-term dynamic relationship among the four factors. The short run analysis reveals that oil price and bitcoin trading volume have little influence on bitcoin price while stock price index has relatively larger impact on it. In the long run, stock price index and oil price have a negative effect on bitcoin price. On the contrary, the value of bitcoin is positively affected by daily trading volume.
Ludvig Backlund
This thesis examines how Distributed Ledger Technologies (DLTs) could be utilized in capital markets in general and in the Nordic capital market in particular. DLTs were introduced with the so called cryptocurrency Bitcoin in 2009 and has in the last few years been of interest to various financial institutions as a means to streamline financial processes. By combining computer scientific concepts such as public-key cryptography and consensus algorithms DLTs make it possible to keep shared databases with limited trust among the participators and without the use of a trusted third party. In this thesis various actors on the Nordic capital market were interviewed and their stance on DLTs were summarized. In addition to this a Proof of Concept of a permissioned DLT application for ownership registration of securities was constructed. It was found that all the interviewees were generally optimistic about DLTs potential to increase the efficiency of capital markets. The technology needs to be adopted to handle the capital markets demand for privacy and large transaction volumes, but there is a general agreement among the interviewees that these issues will be solved. The biggest challenge for an adoption of DLTs seem to lie in that of finding a common industry-wide standard.
Karen Elliott, Fabio Massacci, Chan-Nam Ngo, Julian Williams
No abstract is available for this record.
Philipp Paech
Abstract Since the emergence of the virtual currency Bitcoin in 2009, a new, Internetâbased way of recording entitlements and enforcing rights has increasingly captured the interest of businesses and governments. The technology is commonly called âblockchainâ and is often associated with a closely related phenomenon, the âsmart contractâ. The market is now exploring ways of using these concepts for financial assets, such as securities, fiat money and derivative contracts. This article develops a conceptual framework for the governance of blockchainâbased networks in financial markets. It constructs a vision of how financial regulation and private law should set the boundaries of this new technology in order to protect market participants and societies at large, while at the same time allowing the necessary room for innovation.
Anwar Nasution
No abstract is available for this record.
Melanie Swan
No abstract is available for this record.
Fan Zhang, Ethan Cecchetti, Kyle Croman, Ari Juels ¡ 5 authors
Smart contracts are programs that execute autonomously on blockchains. Their key envisioned uses (e.g. financial instruments) require them to consume data from outside the blockchain (e.g. stock quotes). Trustworthy data feeds that support a broad range of data requests will thus be critical to smart contract ecosystems. We present an authenticated data feed system called Town Crier (TC). TC acts as a bridge between smart contracts and existing web sites, which are already commonly trusted for non-blockchain applications. It combines a blockchain front end with a trusted hardware back end to scrape HTTPSenabled websites and serve source-authenticated data to relying smart contracts. TC also supports confidentiality. It enables private data requests with encrypted parameters. Additionally, in a generalization that executes smart-contract logic within TC, the system permits secure use of user credentials to scrape access-controlled online data sources. We describe TCâs design principles and architecture and report on an implementation that uses Intelâs recently introduced Software Guard Extensions (SGX) to furnish data to the Ethereum smart contract system. We formally model TC and define and prove its basic security properties in the Universal Composability (UC) framework. Our results include definitions and techniques of general interest relating to resource consumption (Ethereumâs âgasâ fee system) and TCB minimization. We also report on experiments with three example applications. We plan to launch TC soon as an online public service.
Bill Marino, Ari Juels
No abstract is available for this record.
Florian Idelberger, Guido Governatori, RĂŠgis Riveret, Giovanni Sartor
No abstract is available for this record.
Max Raskin
No abstract is available for this record.
Alexander Savelyev
The paper analyzes legal issues associated with application of existing contract law provisions to so-called Smart contracts, defined in the paper as âagreements existing in the form of software code implemented on the Blockchain platform, which ensures autonomy and self-executive nature of Smart contract terms based on predetermined set of factorsâ. The paper consists of several sections. In the first section, the paper outlines peculiarities of Blockchain technology as currently implemented in Bitcoin cryptocurrency and which forms the core of Smart contracts. In the second section, the main characteristic features of Smart contracts are described. Finally, the paper outlines key tensions between classic contract law and Smart contracts.. The conclusion section sets the core question for analysis of the perspectives of implementation of this technology by governments: âHow to align the powers of the government with Blockchain if there is no central authority but only distributed technologiesâ. The author suggests two solutions, which are not optimal: 1) providing the state authorities with the status of a Superuser with extra powers and 2) relying on traditional remedies and enforcement practices, by pursuing specific individuals â parties to Smart contract - in offline mode. It is emphasized that those jurisdictions, which have the most Blockchain-friendly regulations will have competitive advantage in attraction of new innovative business models and companies willing to exploit them in a legal way.
Loi Luu, Duc-Hiep Chu, Hrishi Olickel, Prateek Saxena ¡ 5 authors
Cryptocurrencies record transactions in a decentralized data structure called a blockchain. Two of the most popular cryptocurrencies, Bitcoin and Ethereum, support the feature to encode rules or scripts for processing transactions. This feature has evolved to give practical shape to the ideas of smart contracts, or full-fledged programs that are run on blockchains. Recently, Ethereum's smart contract system has seen steady adoption, supporting tens of thousands of contracts, holding millions dollars worth of virtual coins. In this paper, we investigate the security of running smart contracts based on Ethereum in an open distributed network like those of cryptocurrencies. We introduce several new security problems in which an adversary can manipulate smart contract execution to gain profit. These bugs suggest subtle gaps in the understanding of the distributed semantics of the underlying platform. As a refinement, we propose ways to enhance the operational semantics of Ethereum to make contracts less vulnerable. For developers writing contracts for the existing Ethereum system, we build a symbolic execution tool called Oyente to find potential security bugs. Among 19, 336 existing Ethereum contracts, Oyente flags 8, 833 of them as vulnerable, including the TheDAO bug which led to a 60 million US dollar loss in June 2016. We also discuss the severity of other attacks for several case studies which have source code available and confirm the attacks (which target only our accounts) in the main Ethereum network.
Brett Scott
The decentralized digital currency Bitcoin - and its underlying "blockchain" technology - has created much excitement in the technology community, but its potential for building truly empowering social and solidarity-based finance has yet to be tested. This paper provides a primer on the basics of Bitcoin and discusses the existent narratives about the technology´s potential to facilitate remittances, financial inclusion, cooperative structures and even micro-insurance systems. It also flags up potential points of concern and conflict; such as the tech-from-above "solutionism" and conservative libertarian political dynamics of some of the technology start-up community that surrounds Bitcoin. As a way of contrast the paper considers "blockchain 2.0" technologies with more overtly communitarian ideals and their potential for creating "cooperation at scale". It concludes with suggestions for future research.
Neil Gandal, Hanna HaĹaburda
We analyze how network effects affect competition in the nascent cryptocurrency market. We do so by examining early dynamics of exchange rates among different cryptocurrencies. While Bitcoin eventually dominates this market, our data suggest no evidence of a winner-take-all effect early in the market. Indeed, for a relatively long period, a few other cryptocurrencies competing with Bitcoin (the early industry leader) appreciated much more quickly than Bitcoin. The data in this period are consistent with the use of cryptocurrencies as financial assets (popularized by Bitcoin), and not consistent with winner-take-all dynamics. Toward the end of our sample, however, things change dramatically. Bitcoin appreciates against the USD, while other currencies depreciate against the USD. The data in this period are consistent with strong network effects and winner-take-all dynamics. This trend continues as at the time of writing.
Saifedean Ammous
No abstract is available for this record.
Yonatan Sompolinsky, Yoad Lewenberg, Aviv Zohar
No abstract is available for this record.