Smart contracts" are decentralized agreements built in computer code and stored on a blockchain.Proponents imagine a future where commerce takes place exclusively using smart contracts, avoiding the high costs of contract drafting, judicial intervention, opportunistic behavior, and the inherent ambiguities of written language.These decentralized code-only contracts are part of a decades-long quest to eliminate supposed inefficiencies in traditional written agreements.Electronic data interchange (EDI), a contracting technology from the 1970s, was designed with the same goal and garnered similar fanfare.Commentators at the time imagined a revolution in the way firms transacted and a full shift away from anything resembling a paper contract.Ultimately EDI failed to achieve these goals-it empowered, rather than circumvented, human decisionmakers along with their "inefficient" way of forming agreements.In doing so, EDI successfully reduced some transaction costs while preserving efficient forms of contractual flexibility.Smart contracts are indeed more technologically sophisticated than EDI.Smart contract scripting languages offer a broader range of operations and greater scalability.Smart contracts are capable of seamlessly integrating with the operational and financial systems at the core of modern firms, whereas EDI transactions occurred in very early digital environments that required human intermediaries.
The blockchain technology started as the innovation that powered the cryptocurrency Bitcoin. But in recent years, leaders in finance, banking, and many more companies has given this new innovation more attention than ever before. They seek a new technology to replace their system which are often inefficient and costly to operate. However, one of the reasons why it not possible to use a blockchain right away is because of the poor performance. Public blockchains, where anyone can participate, can only process a couple of transaction per second and is therefore far from usable in the world of finance. Permissioned blockchains is another type of blockchain where only a restricted set of users have the rights to decide what will be recorded in the blockchain. This allows permissioned blockchains to have a number of advantages over public blockchains. Most notably is the ability to split the network into segments where only a subset of nodes needs to validate transactions to aparticular application, allowing the use of parallel computing and better scaling. Moreover, the validating nodes can be trusted, allowing the use of consensus algorithm which offer much more through put. In this paper, we compare public blockchain with permissioned blockchain and address the notable trade-offs: decentralization, scalability and security, in the different blockchain networks. Furthermore, we examine the potential of using a permissioned blockchain to replace the old systems used in financial institutes and banks by launching a Hyperledger Fabric network and run stress tests. It is apparent that with less decentralization, the performance and scalability of Hyperledger Fabric network is improved and it is feasible that permissioned blockchain can be used in finance.
Bruno Rodrigues, Thomas Bocek, Andri Lareida, David Hausheer · 6 authors
Abstract The rapid growth in the number of insecure portable and stationary devices and the exponential increase of traffic volume makes Distributed Denial-of-Service (DDoS) attacks a top security threat to services provisioning. Existing defense mechanisms lack resources and flexibility to cope with attacks by themselves, and by utilizing other’s companies resources, the burden of the mitigation can be shared. Emerging technologies such as blockchain and smart contracts allows for the sharing of attack information in a fully distributed and automated fashion. In this paper, the design of a novel architecture is proposed by combining these technologies introducing new opportunities for flexible and efficient DDoS mitigation solutions across multiple domains. Main advantages are the deployment of an already existing public and distributed infrastructure to advertise white or blacklisted IP addresses, and the usage of such infrastructure as an additional security mechanism to existing DDoS defense systems, without the need to build specialized registries or other distribution mechanisms, which enables the enforcement of rules across multiple domains.
In this paper, we explore remarkable similarities between multi-transactional behaviors of smart contracts in cryptocurrencies such as Ethereum and classical problems of shared-memory concurrency. We examine two real-world examples from the Ethereum blockchain and analyzing how they are vulnerable to bugs that are closely reminiscent to those that often occur in traditional concurrent programs. We then elaborate on the relation between observable contract behaviors and well-studied concurrency topics, such as atomicity, interference, synchronization, and resource ownership. The described contracts-as-concurrent-objects analogy provides deeper understanding of potential threats for smart contracts, indicate better engineering practices, and enable applications of existing state-of-the-art formal verification techniques.
Daniele Magazzeni, Peter McBurney, William L. Nash
Smart contracts might encode legal contracts written in natural language to represent the contracting parties' shared understandings and intentions. The issues and research challenges involved in the validation and verification of smart contracts, particularly those running over blockchains and distributed ledgers, are explored.
Smart contracts are computer programs that can be consistently executed by a network of mutually distrusting nodes, without the arbitration of a trusted authority. Because of their resilience to tampering, smart contracts are appealing in many scenarios, especially in those which require transfers of money to respect certain agreed rules (like in financial services and in games). Over the last few years many platforms for smart contracts have been proposed, and some of them have been actually implemented and used. We study how the notion of smart contract is interpreted in some of these platforms. Focussing on the two most widespread ones, Bitcoin and Ethereum, we quantify the usage of smart contracts in relation to their application domain. We also analyse the most common programming patterns in Ethereum, where the source code of smart contracts is available.
Bitcoin, the digital cryptocurrency, has been celebrated as the future of money on the Internet. Although Bitcoin does present several forward-looking innovations, it also integrates a very old concept into its digital architecture: the mining of precious metals. Even though Bitcoin explicitly invokes mining as a metaphor and gold as an example for understanding the cryptocurrency, there has been little critical work on the connections between Bitcoin and previous metalist currency regimes. The following essay proposes a historical comparison with colonial South American silver mining and the global currency regime based on the New World silver peso it created as a way to interrogate Bitcoin. The comparison with colonial South America, and specifically the silver mining economy around the Cerro Rico de Potosí, will help to develop a historical and political understanding of Bitcoin's stakes, including questions of resources, labor, energy, and ecology. Mining and the extractive apparatus that accompanies it always imply massive-scale earthworks that reshape the planet itself, a process known as terraforming. The Potosí comparison will reveal Bitcoin to form part of a similar process of digital primitive accumulation we can provisionally name cryptoforming.
The DPM 2019 and CBT 2019 proceedings present the two ESORICS workshops on data privacy management and cryptocurrencies and blockchain technology. The papers are organized in parts on smart contracts and applications; and payment systems, privacy and mining; privacy preserving data analysis; etc.
Cryptocurrencies, such as bitcoin and ethereum, have not only risen to public attention as novel means of payments, but also as facilitators of initial coin offerings (ICOs, also called token sales). In these entirely online-mediated offerings, entrepreneurs sell tokens registered on a blockchain in exchange for cryptocoins. Buyers receive tokens that can be understood as cryptographically-secured coupons which embody a bundle of rights and obligations. In July 2017, the SEC released an investigative report that highlighted that such tokens can be subject to the full scope of US securities regulation. It is unclear, however, to what extent EU securities regulation is applicable to ICOs and, particularly, whether issuers have to publish and register a prospectus in order to avoid criminal and civil prospectus liability in the EU. In conceptual terms, this depends on whether tokens are considered “securities” under the EU prospectus regulation regime. Against this background, this paper develops a nuanced approach that distinguishes between three archetypes of tokens: currency, investment, and utility tokens. It analyzes the differential implications of each of these types, and their hybrid forms, for EU securities regulation, and develops policy proposals for their regulation.
From the Washington University Senior Honors Thesis Abstracts (WUSHTA), 2017. Published by the Office of Undergraduate Research. Joy Zalis Kiefer, Director of Undergraduate Research and Associate Dean in the College of Arts & Sciences; Lindsey Paunovich, Editor; Helen Human, Programs Manager and Assistant Dean in the College of Arts and Sciences Mentors: Mina Lee and Li Yang
The emergence of financial technology in the last 10 years has created a new type of asset that is Cryptocurrency. Cryptocurreny offers a small transaction fee without involving a third party in its transaction and the ability to make its users anonymous. It became one of its main selling points and was quickly accepted widely in the financial world. Cryptocurrency price movements become volatile. For examples, Bitcoin issued in 2009, the value is not more than USD 10, but in early June 2017, Bitcoin is worth about USD 3000 (Bloomberg, July 5th, 2017). Many investors are interested to invest in Cryptocurrency, especially investors with high risk tolerance. This study aims to find the effects of Cryptocurrency on well-formed portfolios. The assets we use are Foreign Currency, Commodity, Stock, and ETF. The Cryptocurrency we will use is Bitcoin, Ripple and Litecoin. Using the Modern Portfolio Theory approach, we can create an investment portfolio. The results show that the portfolio with Cryptocurrency indeed increases the effectiveness of the portfolio in two ways. The first is to minimize the standard deviation and the second is to create more allocation options for investors to choose from. The optimum allocation of Cryptocurrency is from 5% to 20% depending on the risk tolerance of the investor.
Abstract Cryptocurrencies have left the dark side of the finance universe and become an object of study for asset and portfolio management. Since they have low liquidity compared to traditional assets, one needs to take into account liquidity issues when adding them to a portfolio. We propose a Liquidity Bounded Risk-return Optimization (LIBRO) approach, which is a combination of risk-return portfolio optimization under liquidity constraints. Cryptocurrencies are included in portfolios formed with stocks of the S&P 100, US Bonds, and commodities. We illustrate the importance of the liquidity constraints in an in-sample and out-of-sample study. LIBRO improves the weight optimization in the sense that it only adds cryptocurrencies in tradable amounts depending on the intended investment amount. The returns greatly increase compared to portfolios consisting only of traditional assets. We show that including cryptocurrencies in a portfolio can indeed improve its risk–return trade-off.
The world of money and finance is transforming before our eyes. Digitised assets and innovative financial channels, instruments and systems are creating new paradigms for financial transaction and forging alternative conduits of capital. The Cambridge Centre for Alternative Finance, since its founding in 2015, has been at the forefront of documenting, analysing and indeed critically challenging that digital financial transformation.
This Global Cryptocurrency Benchmarking Study is our inaugural research focused on alternative payment systems and digital assets. Led by Dr Garrick Hileman, it is the first study of its kind to holistically examine the burgeoning global cryptocurrency industry and its key constituents, which include exchanges, wallets, payments and mining.
The findings are both striking and thought-provoking. First, the user adoption of various cryptocurrencies has really taken off, with billions in market cap and millions of wallets estimated to have been ‘active’ in 2016. Second, the cryptocurrency industry is both globalised and localised, with borderless exchange operations, as well as geographically clustered mining activities. Third, the industry is becoming more fluid, as the lines between exchanges and wallets are increasingly ‘blurred’ and a multitude of cryptocurrencies, not just bitcoin, are now supported by a growing ecosystem, fulfilling an array of functions. Fourth, issues of security and regulatory compliance are likely to remain prevalent for years to come.
I hope this study will provide value to academics, practitioners, policymakers and regulators alike. We thank Visa very much for its generous support of independent academic research in this important area.
The aim of this chapter is to situate blockchain-based governance tools within a public value (PV) context, arguing that public governance on the blockchain requires elements of a “public value mindset,” which is comprised of transparency, efficiency, stakeholder salience and participation, innovative thinking, decentralization, and trust. To illustrate this PV mindset, the chapter analogizes the powerful solution put forth by cryptocurrencies towards the “double spending problem,” an issue that had once plagued electronic money, by arguing that the manner in which the double-spending problem was solved by blockchain technology (as best embodied by cryptocurrencies) also offers lessons for public governance on the blockchain, specifically in terms of the PV elements enumerated above. By elucidating the nature of the double-spending problem and the revolutionary solution offered by cryptocurrencies, the chapter advocates for a similar approach in the application of blockchain technologies to public management and governance.
Stefan Dziembowski, Lisa Eckey, Sebastian Faust, Daniel Malinowski
Payment channels emerged recently as an efficient method for performing cheap micropayments in cryptocurrencies. In contrast to traditional on-chain transactions, payment channels have the advantage that they allow for nearly unlimited number of transactions between parties without involving the blockchain. In this work, we introduce Perun, an off-chain channel system that offers a new method for connecting channels that is more efficient than the existing technique of ``routing transactions'' over multiple channels. To this end, Perun introduces a technique called ``virtual payment channels'' that avoids involvement of the intermediary for each individual payment. In this paper we formally model and prove security of this technique in the case of one intermediary, who can be viewed as a ``payment hub'' that has direct channels with several parties. Our scheme works over any cryptocurrency that provides Turing-complete smart contracts. As a proof of concept, we implemented Perun's smart contracts in Ethereum.
Open access
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Blockchain Technology Applications and Security
Cryptography and Data Security
Advanced Steganography and Watermarking Techniques
Joerg Osterrieder, Stephen Chan, Jeffrey Chu, Saralees Nadarajah
We analyze statistical properties of the largest cryptocurrencies (determined by market capitalization), of which Bitcoin is the most prominent example. We characterize their exchange rates versus the U.S. Dollar by fitting parametric distributions to them. It is shown that returns are clearly non-normal, however, no single distribution fits well jointly to all the cryptocurrencies analysed. We find that for the most popular currencies, such as Bitcoin and Litecoin, the generalized hyperbolic distribution gives the best fit, while for the smaller cryptocurrencies the normal inverse Gaussian distribution, generalized t distribution, and Laplace distribution give good fits. The results are important for investment and risk management purposes.
Bitcoin was the first cryptocurrency to use blockchain and has been the market leader since the first bitcoin was mined in 2009. After the birth of Bitcoin with the genesis block, more than 1,000 altcoins and crypto-tokens have been created, with at least 919 trading actively on unregulated or registered exchanges. This entire class of cryptocurrencies and tokens has been classified by some tax authorities as having the same status as commodities. If cryptocurrency is viewed in the same class as commodities, how different is it in terms of its risk and return structure? This article sets out to help readers understand cryptocurrencies and to explore their risk and return characteristics using a portfolio of cryptocurrency represented by the Cryptocurrency Index (CRIX). Substantial discussions are centered on Bitcoin and its close variants. Some questions are raised about the potential of cryptocurrencies as an investment class. Results show that the return correlations between cryptocurrencies and traditional assets are low and that adding CRIX returns to a traditional asset portfolio improves risk–return performance. Sentiment analysis also indicates the CRIX has a relatively high Sharpe ratio. Although we should view the results with care, a new form of financing for cryptocurrency and blockchain start-ups is born. The disruption brought about by Bitcoin may be felt beyond payments through what is known as initial crypto-token offerings or initial token sales. <b>TOPICS:</b>Currency, risk management, performance measurement, mutual funds/passive investing/indexing
Guglielmo Maria Caporale, Luis A. Gil‐Alana, Alex Plastun
This paper examines persistence in the cryptocurrency market. Two different long-memory methods (R/S analysis and fractional integration) are used to analyse it in the case of the four main cryptocurrencies (BitCoin, LiteCoin, Ripple, Dash) over the sample period 2013–2017. The findings indicate that this market exhibits persistence (there is a positive correlation between its past and future values), and that its degree changes over time. Such predictability represents evidence of market inefficiency: trend trading strategies can be used to generate abnormal profits in the cryptocurrency market.