Abstract This paper outlines how the digital currency and network technology of bitcoin functions and explores the context from which it emerged. Bitcoin was conceived in 2008 as an attempt to alleviate trust in government and banks which was at a low during this period of financial crisis. However, with bitcoin trust does not dissipate, rather it shifts. Trust moves from trust in banks or states to trust in algorithms and encryption software. There is a move from conventional trust in the gold standard—“In Gold We Trust”—to the trust announced on U.S. currency—“In God We Trust”—to trust in software and networks—“In Digital We Trust”. The hyperbole of bitcoin discourse is deemed to be an expression of the Californian Ideology, which itself often conceals a right-wing agenda. The paper analyses the hype behind the celebration of decentralised digital networks. It proposes that a form of network fetishism operates here. The failure of bitcoin as a currency (rather than as a hoarded commodity in an emergent bubble) and as an idea might be attributed to the failure to see how ultra-modern digital networks conceal very traditional consolidation of power and capital. The rise and fall of bitcoin, in terms of its original ambition, serves as a cautionary tale in the digital age—it reveals how ingenious innovations that might challenge power and the consolidation of capital become co-opted and colonised by capital. Finally, the paper offers a discussion of the possible progressive uses of the digital technology bitcoin has facilitated.
O objetivo do artigo consiste em responder ao seguinte problema de pesquisa: a falta de regulamentação específica para as criptomoedas possui relação com a expansão das modalidades criminosas? Para responder ao referido problema, é necessário abordar o conceito de criptomoedas, sua expansão, o papel das instituições de controle e os limites jurídicos que reconhecem a existência dessa nova modalidade de tecnologia. Partimos do suposto de que o advento das criptomoedas em si não consiste em uma atividade criminosa pela ausência de regulamentação pelo Banco Central, mas sim, pode vir a se encaixar em tipos penais pelo mau uso dos softwares. A abordagem é qualitativa, com suporte em revisão de literatura e análise descritiva dos fenômenos pesquisados, além da consulta sobre a legislação sobre o tema. A contribuição é relevante pelo ineditismo e pela importância do tema no contexto financeiro e jurídico das transações realizadas em modalidade virtual. Conclui-se que não é possível associar diretamente o uso de bitcoins com a expansão das modalidades criminosas, entretanto, resta evidente que há relação subjacente entre a falta de regulamentação e a especialização de práticas criminosas que usam o ciberespaço como ambiente.
Rodrigo Valente Giublin Teixeira, Felipe Rangel da Silva
Pelo presente se busca analisar o fenômeno da moeda eletrônica Bitcoin e o impacto jurídico por esta causado, especialmente no que cerne ao confronto aparente com a soberania estatal, uma vez que dada sua internacionalidade e a dificuldade ou impossibilidade de proibição do uso, poder-se-ia em um primeiro momento vislumbrar ofensa ao instituto jurídico, o que será desmistificado. Para tanto, utilizou-se de pesquisa bibliográfica, especialmente estrangeira, dado o ainda ineditismo do tema, com autores de áreas distintas da ciência jurídica, pois assim exigido para análise das questões técnicas de funcionamento da ferramenta e também para delimitação do impacto financeiro causado pela nova moeda, emprestando conceitos e institutos da ciência econômica para aplicação. Contudo, apesar de necessário, o aprofundamento interdisciplinar se restringe ao suficiente para possibilitar a análise jurídica, a qual se dá, por sua vez, em âmbito de Direito Público, não se tendo conhecimento de análise anterior realizada sob o mesmo prisma.
Feb 6, 2018·Caginalp, C., & Caginalp, G. (2018). Opinion: Valuation, liquidity price, and stability of cryptocurrencies. Proceedings of the National Academy of Sciences, 115(6), 1131-1134
Cryptocurrencies are examined through the asset flow equations and experimental asset markets. Since tangible value of a typical cryptocurrency is non-existent, the theory suggests that price will gravitate toward liquidity value, i.e., the total amount of cash available for purchase of the asset divided by the number of units. Thus it is unlikely that cryptocurrencies in their current form will be stable in the absence of a mechanism of a link to value.
Cross-institutional healthcare predictive modeling can accelerate research and facilitate quality improvement initiatives, and thus is important for national healthcare delivery priorities. For example, a model that predicts risk of re-admission for a particular set of patients will be more generalizable if developed with data from multiple institutions. While privacy-protecting methods to build predictive models exist, most are based on a centralized architecture, which presents security and robustness vulnerabilities such as single-point-of-failure (and single-point-of-breach) and accidental or malicious modification of records. In this article, we describe a new framework, ModelChain, to adapt Blockchain technology for privacy-preserving machine learning. Each participating site contributes to model parameter estimation without revealing any patient health information (i.e., only model data, no observation-level data, are exchanged across institutions). We integrate privacy-preserving online machine learning with a private Blockchain network, apply transaction metadata to disseminate partial models, and design a new proof-of-information algorithm to determine the order of the online learning process. We also discuss the benefits and potential issues of applying Blockchain technology to solve the privacy-preserving healthcare predictive modeling task and to increase interoperability between institutions, to support the Nationwide Interoperability Roadmap and national healthcare delivery priorities such as Patient-Centered Outcomes Research (PCOR).
Existing Byzantine fault tolerance (BFT) protocols face significant challenges in the consortium blockchain scenario. On the one hand, we can make little assumptions about the reliability and security of the underlying Internet. On the other hand, the applications on consortium blockchains demand a system as scalable as the Bit-coin but providing much higher performance, as well as provable safety. We present a new BFT protocol, Gosig, that combines crypto-based secret leader selection and multi-round voting in the protocol layer with implementation layer optimizations such as gossip-based message propagation. In particular, Gosig guarantees safety even in a network fully controlled by adversaries, while providing provable liveness with easy-to-achieve network connectivity assumption. On a wide area testbed consisting of 140 Amazon EC2 servers spanning 14 cities on five continents, we show that Gosig can achieve over 4,000 transactions per second with less than 1 minute transaction confirmation time.
Roberto Tonelli, G. A. Pierro, Marco Ortu, Giuseppe Destefanis
Smart contracts (SC) are software programs that reside and run over a blockchain. The code can be written in different languages with the common purpose of implementing various kinds of transactions onto the hosting blockchain. They are ruled by the blockchain infrastructure with the intent to automatically implement the typical conditions of traditional contracts. Programs must satisfy context-dependent constraints which are quite different from traditional software code. In particular, since the bytecode is uploaded in the hosting blockchain, the size, computational resources, interaction between different parts of the program are all limited. This is true even if the specific programming languages implement more or less the same constructs as that of traditional languages: there is not the same freedom as in normal software development. The working hypothesis used in this article is that Smart Contract specific constraints should be captured by specific software metrics (that may differ from traditional software metrics). We tested this hypothesis on 85K Smart Contracts written in Solidity and uploaded on the Ethereum blockchain. We analyzed Smart Contracts from two repositories "Etherscan" and "Smart Corpus" and we computed the statistics of a set of software metrics related to Smart Contracts and compared them to the metrics extracted from more traditional software projects. Our results show that generally, Smart Contract metrics have more restricted ranges than the corresponding metrics in traditional software systems. Some of the stylized facts, like power law in the tail of the distribution of some metrics, are only approximate but the lines of code follow a log-normal distribution which reminds us of the same behaviour already found in traditional software systems.
This paper is inspired by the project proposal ID 7807232014 submitted for the EU Horizon 2020 topic ICT-11-2017 in April 25, 2017. It aims at applying state-of-the-art ICT technologies, systems and functions such as Cloud/Fog and IoT to enable food supply chain. A new approach will lead to trusted cooperative applications and services within the agro-food chains. Blockchain technologies will enhance the transparency, information flow and management capacity allowing better interactions of farmers with other part of supply chain, especially the consumer. Our research will provide better performing value chains by proposing new food-on-demand business model, based on new Quality of Experience (QoE) food metrics, bridging the gap between subjective experience and objective matrics based on quality standards. Finally, we provided an awareness qustionaire for fresh food products (FFP) and survay for a group of 30 students from the University of Skopje. This study showed that the majority of students are aware and focused just on few common FFP aspects without deeper knowledge of FFP quality.
Jia Liu, Tibor Jager, Saqib A. Kakvi, Bogdan Warinschi
Time-lock encryption is a method to encrypt a message such that it can only be decrypted after a certain deadline has passed. We propose a novel time-lock encryption scheme, whose main advantage over prior constructions is that even receivers with relatively weak computational resources should immediately be able to decrypt after the deadline, without any interaction with the sender, other receivers, or a trusted third party. We build our time-lock encryption on top of the new concept of computational reference clocks and an extractable witness encryption scheme. We explain how to construct a computational reference clock based on Bitcoin. We show how to achieve constant level of multilinearity for witness encryption by using SNARKs. We propose a new construction of a witness encryption scheme which is of independent interest: our scheme, based on Subset-Sum , achieves extractable security without relying on obfuscation. The scheme employs multilinear maps of arbitrary order and is independent of the implementations of multilinear maps.
Today's vehicles are becoming cyber-physical systems that not only communicate with other vehicles but also gather various information from hundreds of sensors within them. These developments help create smart and connected (e.g., self-driving) vehicles that will introduce significant information to drivers, manufacturers, insurance companies, and maintenance service providers for various applications. One such application that is becoming crucial with the introduction of self-driving cars is forensic analysis of traffic accidents. The utilization of vehicle-related data can be instrumental in post-accident scenarios to discover the faulty party, particularly for self-driving vehicles. With the opportunity of being able to access various information in cars, we propose a permissioned blockchain framework among the various elements involved to manage the collected vehicle-related data. Specifically, we first integrate vehicular public key infrastructure (VPKI) to the proposed blockchain to provide membership establishment and privacy. Next, we design a fragmented ledger that will store detailed data related to vehicles such as maintenance information/ history, car diagnosis reports, and so on. The proposed forensic framework enables trustless, traceable, and privacy-aware post-accident analysis with minimal storage and processing overhead.
Artiklen betragter udviklingen i værdien af Bitcoin og stiller spørgsmålet, om der er en boble i Bitcoin - eller om prisudviklingen kan forklares ved nogle mere fundamentale karakteristika ved denne og andre kryptovalutaer eller måske af nogle teknoøkonomiske udviklingstendenser. Det er svært at komme med et entydigt svar på spørgsmålet, men ifølge artiklen er der flere forhold, der tyder på en boble.
Blockchain allows for decentralized, self-regulating data, ultimately creating a shared infrastructure where transactions are saved and stored. Scientific information in its essence is a large, dynamic body of information and data that is collaboratively created, altered, used and shared. It lends itself well to the blockchain technology because that technology has the potential to solve challenges around peer review, irreproducibility, and metrics. Other applications of blockchain technology such as cryptocurrencies and digital rights management systems also have a potential relevance for academic publishing.
Can a monetary system in which privately issued cryptocurrencies circulate as media of exchange work? Is such a system stable? How should governments react to digital currencies? Can these currencies and government-issued money coexist? Are cryptocurrencies consistent with an e cient allocation? These are some of the important questions that the sudden rise of cryptocurrencies has brought to contemporary policy discussions. To answer these questions, we construct a model of competition among privately issued at currencies. We nd that a purely private arrangement fails to implement an e cient allocation, even though it can deliver price stability under certain technological conditions. Currency competition creates problems for monetary policy implementation under conventional methods. However, it is possible to design a policy rule that uniquely implements an e cient allocation by driving private currencies out of the market. We also show that unique implementation of an e cient allocation can be achieved without government intervention if productive capital is introduced.
Med introduktionen af et futures-marked er Bitcoin-eksponering blevet tilgængelig for en bredere gruppe af investorer, som hidtil ikke har kunnet eller villet tilgå det underliggende marked for Bitcoin. Artiklen finder, at kontrakterne umiddelbart favoriserer spekulanter på bekostning af hedgers og arbitragører, og analyserer, hvorledes futures-priserne kan indeholde væsentlig information om spekulaternes forventning til den fremtidige prisudvikling.
Setting proprietary standards for elemental data components of financial transactions, once the province of market participants and intermediaries, their sovereign regulators, and software and data vendors, has evolved into a global open source standards requirement. Global data standards initiatives are now seeking to eliminate unnecessary infrastructure costs and risks arising from use of proprietary data and interoperability standards and processes. Data standards have taken on new meaning and urgency as they have also become a prerequisite to securing financial networks from cyberattacks and enabling new technologies of the digital age. A new generation of innovation led by distributed ledger technology (DLT), a supportive database technology of the Blockchain, is being actively pursued by financial institutions and their financial market utilities. It is also of interest to many financial market regulators who are requesting access to more granular standardised transactional data. It has tremendous potential to eliminate reconciliation processes at financial institutions and refocus many of the hundreds of data intermediaries and financial market utilities that play a significant role in reconciling risk prone and costly non-standard data. This paper argues that the components of a sustainable financial industry infrastructure rebuild are coming into existence, but uncoordinated efforts across the globe will stifle the effectiveness of these changes. Therefore, this paper proposes a new global industry/ government partnership to coordinate implementation of data identification standards, accelerate data harmonisation initiatives and sponsor a secure financial-sector DLT protocol standard.
S. Nakamoto präsentierte 2008 eine Peer-to-Peer Version von elektronischem Geld: Bitcoin. Dieses System ermöglicht den direkten Zahlungsverkehr zwischen verschiedenen Personen und Organisationen, ohne Finanzdienstleister oder andere zu-vertrauende Dritte als Intermediäre einsetzen zu müssen. Im Zuge dessen entwickelte er die erste praktische Lösung für das Problem der Konsensfindung innerhalb eines dynamischen Netzwerks von potentiell anonymen Knoten, ohne die Notwendigkeit diese zuvor festzulegen. Dieses Ergebnis wird auf Basis des Konzepts von Proof-of-Work erzielt, das auf Grund der hohen Anforderungen für die benötigten Berechnungen zu einem enormen Energieverbrauch führt. Unter Verwendung des alternativen Prinzips von Proof-of-Stake versuchen neue Protokolle Nakamoto's Ansatz weiterzuentwickeln. Eine grundlegende Voraussetzung für die Sicherheit dieser Protokolle ist eine vertrauenswürdige (d. h. öffentlich-verifizierbare und manipulationssichere) Quelle von Zufallszahlen. Deren Erzeugung stellt ein komplexes Problem dar, da diese in einem dezentralen Netzwerk unter dem potentiellen Einfluss von Angreifern durchgeführt wird. Kürzlich veröffentlichte Forschungsergebnisse und Projekte aus der Wirtschaft beschäftigen sich mit diesem Problem und stellen sogenannte Random Beacon Protokolle vor, welche die erforderlichen Zufallszahlen in regelmäßigen Intervallen generieren. Diese Diplomarbeit beschäftigt sich intensiv mit den Herausforderungen der Entwicklung von Random Beacon Protokollen und liefert den ersten detaillierten Vergleich. Es wird gezeigt, dass Publicly-Verfiable Secret Sharing (PVSS) in vielen dieser Ansätze als gemeinsame Komponente dient. Weiters präsentiert diese Arbeit ein neu entwickeltes Protokoll, das ebenfalls PVSS verwendet und die Skalierbarkeit im Vergleich zu den bereits existierenden deutlich verbessert. Da dieser neue Ansatz nur eine PVSS-Instanz pro Runde benötigt, verringert sich der Kommunikationsaufwand von O(n³) auf O(n²). Diese Verbesserung wird erzielt, ohne auf wichtige Protokolleigenschaften, wie öffentliche Verifizierbarkeit, Manipulationssicherheit oder Nichtvorhersagbarkeit, verzichten zu müssen. Darüber hinaus erfolgt eine Optimierung der erarbeiteten Lösung durch die Entwicklung einer Protokollerweiterung, die die Interaktion zwischen den Knoten weiter reduziert und einen nahezu optimalen Kommunikationsaufwand von O(n c) erreicht. Dennoch stellt das erweiterte Protokoll mit sehr großer Wahrscheinlichkeit sicher, dass Zufallszahlen kontinuierlich erzeugt werden können und diese weder manipulierbar noch vorhersagbar sind.
Mikael Asplund, Jakob Lövhall, Simin Nadjm‐Tehrani
The possibility of in-store payments would further increase the potential usefulness of cryptocurrencies. However, this would require much faster transaction verification than current solutions provide (one hour for Bitcoin) since customers are likely not prepared to wait a very long time for their purchase to be accepted by a store. We propose a solution for enabling in-store payments with waiting times in the order of a few seconds, which is still compatible with the current Bitcoin protocol. The idea is based on a payment card in combination with a protocol for ensuring that losing a card does not mean losing the money on it. We analyse the required transaction verification delay and also the potentially added risks that the solution brings compared to current systems.
Open access
Blockchain Technology Applications and Security
IoT and Edge/Fog Computing
Advanced Steganography and Watermarking Techniques
This piece of work is aimed at arguing the advantages and disadvantages as well as the challenges of the blockchain technology and if this distributed ledger system, has the potential to replace current regulatory bodies and intermediaries in the financial services sector, specifically in terms of identity management and more generally. This would seem to have been the vision of the originators of the technology back in 2009/10. To create a self-sustainable, secure environment for transactions of monetary nature. In this piece of work, it is the intention to follow a specific argument in order to demonstrate that this “original idea” is not something which is likely to survive or become main stream. Rather, arguments will be made to demonstrate that likely there will be a hybrid of “old” and “new” emerging. The solution suggested to harvest the full potential of those new emerging technologies, amongst others, customer identity management, is to streamline existing processes by involving regulatory bodies in the process of setting up new services for transacting and managing identities, as the need for oversight, due to technological flaws, cannot be argued away completely.
In the Internet economy, with the help of cryptography, a branch of mathematics dealing with the security of information, as well as authentication and restriction of access to a computer system, a new digital coin as an alternative to national currencies appeared. In accomplishing this, using both mathematical methods (taking advantage of, for example, the difficulty of factorizing very large numbers), and quantum encryption methods. Throughout the world, information technology companies are focusing on information protection, inventing day-to-day methods with greater durability. In the horizon of Information Security, Quantum Cryptography has emerged, generating new possibilities in that field, hoping that data will be better protected and that the digital currency will resist over time and eventually evolve in the future, although Kurzweil, Bitcoin's pioneering technology is unlikely to be used in this respect. The idea of virtual alternatives to national currencies is not new, with advantages and disadvantages. The advantages of this coin are high payment freedom, transparency of information, high security, reduced risks for traders. Among the disadvantages we highlight the risk and volatility, the lack of notification and understanding, with incomplete functions, but which are developing, so Bitcoin is not perfect.
Long Finance's Distributed Futures research programme is pleased to announce the launch the report “The Quantum Countdown: Quantum Computing & The Future Of Distributed Ledger Encryption”, another in a series of exciting projects in the programme.
Smart Ledgers are based on a combination of mutual distributed ledgers (aka block-chain: multi-organisational databases with a super audit trail) with embedded programming and sensing, thus permitting semi-intelligent, autonomous transactions. Smart Ledgers are touted as a technology for fair play in a globalized world. There are numerous projects building trade systems using this technology with announcements from governments, shipping firms, large IT firms, and the like. The research is intended to inform policy makers and business people making decisions about moving towards these systems.
This report is about a major threat to the security of Smart Ledgers and other systems from quantum computing. If and when large-scale quantum computers become available, there is a concern that such computers would be able to break the security of widely-used public key cryptography, which allows remote parties to communicate securely and authenticate transactions and data without sharing a secret key in advance. Fortunately, there are good solutions to this problem, and better ones are emerging. The hard questions for individual computer system operators involve when and how to address the problem, given its uncertain timing and the evolving solutions. The report seeks to explain the problem in detail for both non-technical and technical readers, starting with the essentials of cryptography, quantum computing, and how quantum computing threatens public key cryptography. It then considers the available solutions to the problem, and provides frameworks for deciding when and how to respond to it.
Smart contracts gain rapid exposure since the inception of blockchain<br/>technology. Today's smart contracts are coded in non-mainstream<br/>procedural programming languages (e.g. Solidity for Ethereum),<br/>which lifts the requirement to draft enterprise ready smart contract to<br/>both a legal professional and a programmer instead of only the former.<br/>In search for a smart contract language that reduces the threshold to<br/>draft one, this conceptual paper elaborates how business logic can be<br/>converted to executable code for commitment-based smart contracts.<br/>Hereby, a contract is viewed as a set of reciprocal commitments. The<br/>smart contract ensures the automated execution of all or most of these<br/>commitments. In order to leverage its event processing capabilities,<br/>Reaction RuleML has been used to appropriately represent the<br/>elements and working of passive and active rules within a<br/>commitment based smart.
The recent explosion of interest in blockchains led to a plethora of proposals for their application, including attempts to decentralize some centralized network functions. At the same time, real "distributed wireless networks" are emerging. Community networks, for instance, are large mesh networks made of hundreds of nodes built by communities primarily to solve digital divide, and they are thriving. The challenges these networks face are not only technological: they deal with creating incentives to participate, with the business model they may adopt, and with their internal governance. Very few models have been proposed to apply blockchains to bottom-up distributed networks: we instead expose how they can solve many problems which so far hindered the diffusion of such networks. Maybe we can push this further: a network is, in essence, a system in which all nodes find a rough consensus on the best paths to connect a node with another. Can we use this consensus method to run a distributed ledger and a cryptocurrency within the network itself, rather than simply applying to networks the effects of a blockchain defined in a separate system? This paper introduces this concept, named "Proof of Networking", and discusses its potential avails.
Blockchain technology has attracted increasing attention in recent years. One reason of this new trend is the introduction of on-chain smart contracts enabling the implementation of decentralized applications in trust-less environments. Along with its adoption, attacks exploiting smart contract vulnerabilities are inevitably growing. To counter these attacks and avoid breaches, several approaches have been explored such as documenting vulnerabilities or model checking using formal verification. However, these approaches fail to capture the Blockchain and users behavior properties. In this paper, we propose a novel formal modeling approach to verify a smart contract behavior in its execution environment. We apply this formalism on a concrete smart contract example and analyze its breaches with a statical model checking approach.
One of the most popular platform based on blockchain technology is Ethereum. Internal activity on this public blockchain is analyzed both from a quantitative and qualitative point of view. In a first part, it is shown that the creation of the Ethereum Alliance consortium has been a game changer in the use of the technology. In a second part, the network robustness against attacks is investigated from a graph point of view, as well as the distribution of internal activity among users. Addresses of great influence were identified, and allowed to formulate conjectures on the current usage of this technology.