Follow blockchain research across journals, conferences, and preprint repositories.
95,621 results · page 3572 of 3,985
Peng Xie, Hailiang Chen, Yu Jeffrey Hu
No abstract is available for this record.
Kristoffer Nærland, Christoph Müller-Bloch, Roman Beck, Søren Palmund
Many decentralized, inter-organizational environments such as supply chains are characterized by high transactional uncertainty and risk. At the same time, blockchain technology promises to mitigate these issues by introducing certainty into economic transactions. This paper discusses the findings of a Design Science Research project involving the construction and evaluation of an information technology artifact in collaboration with Maersk, a leading international shipping company, where central documents in shipping, such as the Bill of Lading, are turned into a smart contract on blockchain. Based on our insights from the project, we provide first evidence for preliminary design principles for applications that aim to mitigate the transactional risk and uncertainty in decentralized environments using blockchain. Both the artifact and the first evidence for emerging design principles are novel, contributing to the discourse on the implications that the advent of blockchain technology poses for governing economic activity.
Yuqin Xu, Shangli Zhao, Lanju Kong, Yongqing Zheng · 6 authors
No abstract is available for this record.
Nicolas T. Courtois, Rebekah Mercer
Bitcoin is an open source payment system with a market capitalization of about 15 G$. During the years several key management solutions have been proposed to enhance bitcoin. The common characteristic of these techniques is that they allow to derive public keys independently of the private keys, and that these keys match. In this paper we overview the historical development of such techniques, specify and compare all major variants proposed or used in practical systems. We show that such techniques can be designed based on 2 distinct ECC arithmetic properties and how to combine both. A major trend in blockchain systems is to use by Stealth Address (SA) techniques to make different payments made to the same payee unlikable. We review all known SA techniques and show that early variants are less secure. Finally we propose a new SA method which is more robust against leakage and against various attacks.
Masashi Hayano, Yuki Miyashita, Toshiharu Sugawara
No abstract is available for this record.
Robert Connell
The primary concern in this dissertation is the question of how racially marginalized societies practicing autonomous governance negotiate conflicts with sovereign states over resource extraction and its consequences. Specifically, this research provides a description, interpretation, and analysis of contemporary social organization and governance of the Maroon polity of Accompong as it brings to bear a distinct history of resistance onto the terrain of political conflict and negotiations with the Jamaican state. The Ndyuka Maroon polities of the Moengo region of Suriname are used as a comparative example where, like Jamaica, the activities of the aluminum industry are the fulcrum of an environmental and political crisis threatening Maroon territorial and cultural integrity. Standing as the first comparison of these two Maroon societies in the contemporary period, this research reveals that Accompong has developed political strategies of separatism and sovereignty while seeking stability with the Jamaican state, whereas the Ndyuka have eschewed separatism in favor of state entryism. These divergent strategies are responses to the differential tolerances of each national state toward Maroon autonomy given political economic calculations based on the valuation of Maroon land for its resource wealth. Yet, in both Maroon communities, a practice of environmental preservationism grounded in distinct collective memories of resistance to enslavement has guided their responses to the crisis. Ultimately, 21st century Maroon political action suggests the need for plurinational and decentralized approaches to national state formation. This research uses systematic empirical data, articulated through an engagement with key theories in both African Diaspora Studies and Environmental Studies, to create a generative conversation between the two fields. This research contributes to a greater understanding of environmental politics, ethnic multiplicity in the African diaspora, the politics of autonomy, diaspora theory, Caribbean colonial history, socio-economic development in developing countries, and the lateral possibilities of freedom and social transformation.
Jesper Buus Nielsen
No abstract is available for this record.
González Ulloa, Alonso Emilio
No abstract is available for this record.
Rafaël del Pino, Vadim Lyubashevsky, Gregory Neven, Gregor Seiler
We propose a lattice-based electronic voting scheme, EVOLVE (Electronic Voting from Lattices with Verification), which is conjectured to resist attacks by quantum computers. Our protocol involves a number of voting authorities so that vote privacy is maintained as long as at least one of the authorities is honest, while the integrity of the result is guaranteed even when all authorities collude. Furthermore, the result of the vote can be independently computed by any observer. At the core of the protocol is the utilization of a homomorphic commitment scheme with strategically orchestrated zero-knowledge proofs: voters use approximate but efficient "Fiat-Shamir with Aborts" proofs to show the validity of their vote, while the authorities use amortized exact proofs to show that the commitments are well-formed. We also present a novel efficient zero-knowledge proof that one of two lattice-based statements is true (so-called OR proof) and a new mechanism to control the size of the randomness when applying the homomorphism to commitments. We give concrete parameter choices to securely instantiate and evaluate the efficiency of our scheme. Our prototype implementation shows that the voters require $8$ milliseconds to submit a vote of size about $20$KB to each authority and it takes each authority $0.15$ seconds per voter to create a proof that his vote was valid. The size of the vote share that each authority produces is approximately $15$KB per voter, which we believe is well within the practical bounds for a large-scale election.
Rafaël del Pino, Vadim Lyubashevsky
For a linear function f, a vector \(\mathbf{x}\) with small coefficients, and a vector \(y=f(\mathbf{x})\), we would like to be able to give a zero-knowledge proof for the knowledge of an \(\mathbf{x}'\) with small coefficients that satisfies \(f(\mathbf{x}')=y\). This is a common scenario in lattice-based cryptography, and there is currently no satisfactory solution for this problem. All known protocols are built via the repetition of a basic protocol that only has constant (1/2 or 2/3) soundness error. This implies that the communication complexity of the final protocol will be at least a factor of k larger than that of the basic one, where k is the security parameter.
Foteini Baldimtsi, Jan Camenisch, Maria Dubovitskaya, Anna Lysyanskaya · 7 authors
Membership revocation is essential for cryptographic applications, from traditional PKIs to group signatures and anonymous credentials. Of the various solutions for the revocation problem that have been explored, dynamic accumulators are one of the most promising. We propose Braavos, a new, RSA-based, dynamic accumulator. It has optimal communication complexity and, when combined with efficient zero-knowledge proofs, provides an ideal solution for anonymous revocation. For the construction of Braavos we use a modular approach: we show how to build an accumulator with better functionality and security from accumulators with fewer features and weaker security guarantees. We then describe an anonymous revocation component (ARC) that can be instantiated using any dynamic accumulator. ARC can be added to any anonymous system, such as anonymous credentials or group signatures, in order to equip it with a revocation functionality. Finally, we implement ARC with Braavos and plug it into Idemix, the leading implementation of anonymous credentials. This work resolves, for the first time, the problem of practical revocation for anonymous credential systems.
Hitoshi Okada, Shigeichiro Yamasaki, Vanessa Bracamonte
The potential of blockchain technology has received attention in the area of FinTech - the combination of finance and technology. Blockchain technology was first introduced as the technology behind the Bitcoin decentralized virtual currency, but there is the expectation that its characteristics of accurate and irreversible data transfer in a decentralized P2P network could make other applications possible. Although a precise definition of blockchain technology has not yet been given, it is important to consider how to classify different blockchain systems in order to better understand their potential and limitations. The goal of this paper is to add to the discussion on blockchain technology by proposing a classification based on two dimensions external to the system: (1) existence of an authority (without an authority and under an authority) and (2) incentive to participate in the blockchain (market-based and non-market-based). The combination of these elements results in four types of blockchains. We define these dimensions and describe the characteristics of the blockchain systems belonging to each classification.
Chris Dannen
In the preceding chapter, you learned how to use Solidity to create instructions for the Ethereum Virtual Machine. However, you stopped short of uploading your program to the EVM, a process known generally in computer application development as deployment . This chapter presents the process by which you can deploy your Solidity scripts to the EVM, making them available as a real product or service. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
Sarah Meiklejohn, Rebekah Mercer
Cryptocurrencies allow users to securely transfer money without relying on a trusted intermediary, \nand the transparency of their underlying ledgers also enables public verifiability. This openness, \nhowever, comes at a cost to privacy, as even though the pseudonyms users go by are not linked to their \nreal-world identities, all movement of money among these pseudonyms is traceable. In this paper, \nwe present M¨obius, an Ethereum-based tumbler or mixing service. M¨obius achieves strong notions of \nanonymity, as even malicious senders cannot identify which pseudonyms belong to the recipients to \nwhom they sent money, and is able to resist denial-of-service attacks. It also achieves a much lower \noff-chain communication complexity than all existing tumblers, with senders and recipients needing \nto send only two initial messages in order to engage in an arbitrary number of transactions.
Chris Dannen
Many of civilization’s most nagging imperfections could become the domain of blockchain’s killer apps. For developers, designers, and product managers, there’s no better time to begin prototyping applications for the Ethereum network. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
Nashirah Abu Bakar, Sofian Rosbi
Cryptocurrency is a digital currency designed to work as a medium of exchange using cryptography to secure the transactions, to control the creation of additional units, and to verify the transfer of assets. The objective of this study is to evaluate the volatility condition for cryptocurrency (Bitcoin) exchange rate and return. Volatility calculated as standard deviation of logarithmic returns. This study performed normality test using Shapiro-Wilk method. Then, the high volatility detection performed using box-whisker plot and statistical process control chart. In descriptive statistical analysis, the mean for Bitcoin return is 0.006 and the deviation is 0.04458. The standard error indicates the volatility for Bitcoin is 4.458 %. This value is considered as high value of volatility.High value of volatility indicates the investment in Bitcoin is categorical as high risk investment. The important of this study is to assist investors to develop better investment portfolio in targeting better profit and lowering the loss
T. Todorov
Bitcoin is a type of crypto-currency that was launched in January 2009 as an emerging digital phenomenon in the financial technology realm by an unknown computer scientist using the pseudonym Satoshi Nakamoto. It is an innovative and independent currency that uses cryptography for its creation and for performing secure transactions. The aim of this article is targeted to introducing into the bitcoin's technology. The survey results and empirical research show that despite the bitcoin benefits over the currency of central authority people do not believe in this crypto-currency because of its speculative character.
Robert Parham
No abstract is available for this record.
Dirk G. Baur, Thomas Dimpfl, Konstantin Kuck
No abstract is available for this record.
Jennifer Hongbo Jiang
Thesis: S.M. in Management of Technology, Massachusetts Institute of Technology, Sloan School of Management, 2017.
Zachary C. Kennedy, David Stephenson, Josef F. Christ, Timothy R. Pope · 7 authors
An anti-counterfeiting method is introduced by doping optically-active nanomaterials into printed parts, non-destructively measuring the part's chemical signatures arising from the taggants, and linking the resulting signature data to a blockchain.
Jonathan Rohr, Aaron Wright
Best known for their role in the creation of cryptocurrencies like bitcoin, blockchains are revolutionizing the way technology entrepreneurs finance their business enterprises. In 2017 alone, tech entrepreneurs raised over $6 billion through the sale of blockchain-based digital tokens, with some sales lasting mere seconds before selling out. In a token sale, also referred to as an “initial coin offering” or “ICO,” organizers of a project sell digital tokens to members of the public to finance the development of new technological platforms and services. After the initial sale, cryptocurrency exchanges scattered across the globe list tokens for trading and facilitate an active secondary market in which wild price fluctuations are common.\nThe recent explosion of token sales could mark the beginning of a broader shift in public capital markets. Blockchains drastically reduce the cost of exchanging value and enable anyone to transmit digitized assets around the globe in a highly trusted manner, stoking dreams of truly global capital markets that leverage the power of a blockchain and the Internet to facilitate capital formation. Lacking homogeneity, the status of tokens under U.S. securities laws is unclear. Although the SEC recently issued a Report of Investigation and has initiated several enforcement actions in which it has found that tokens are securities, confusion still surrounds the boundaries between the types of tokens that will be treated as securities and those that will not.\nIn this Article, we argue that the SEC and Congress should provide token sellers and the exchanges that facilitate token sales with additional regulatory certainty and a sensible path to compliance. Specifically, we outline extrinsic and intrinsic factors that courts and regulators should consider when applying the Howey test to digital tokens, adoption of which would help resolve the uncertainty surrounding tokens that mix aspects of consumption and use with the potential for profit. We further propose that lawmakers adopt both a compliance-driven safe harbor for online exchanges that list tokens with a reasonable belief that the public sale of such tokens is not a violation of section 5 of the Securities Act of 1933 as well as an exemption to the section 5 registration requirement that has been tailored to digital tokens.
Michael Fröwis, Rainer Böhme
No abstract is available for this record.
Loi Luu, Yaron Velner, Jason Teutsch, Prateek Saxena
Cryptocurrencies such as Bitcoin and Ethereum are operated by a handful of mining pools. Nearly 95% of Bitcoin's and 80% of Ethereum's mining power resides with less than ten and six mining pools respectively. Although miners benefit from low payout variance in pooled mining, centralized mining pools require members to trust that pool operators will remunerate them fairly. Furthermore, centralized pools pose the risk of transaction censorship from pool operators, and open up possibilities for collusion between pools for perpetrating severe attacks. In this work, we propose SMARTPOOL, a novel protocol design for a decentralized mining pool. Our protocol shows how one can leverage smart contracts, autonomous blockchain programs, to decentralize cryptocurrency mining. SMARTPOOL gives transaction selection control back to miners while yielding low-variance payouts. SMARTPOOL incurs mining fees lower than centralized mining pools and is designed to scale to a large number of miners. We implemented and deployed a robust SMARTPOOL implementation on the Ethereum and Ethereum Classic networks. To date, our deployed pools have handled a peak hashrate of 30 GHs from Ethereum miners, resulting in 105 blocks, costing miners a mere 0:6% of block rewards in transaction fees.