This paper presents LinBFT, a novel Byzantine fault tolerance (BFT) protocol for blockchain systems that achieves amortized O(n) communication volume per block under reasonable conditions (where n is the number of participants), while satisfying determinist guarantees on safety and liveness. This significantly improves previous results, which either incurs quadratic communication complexity, or only satisfies safety in a probabilistic sense. LinBFT is based on the popular PBFT protocol, and cuts down its $O(n^4)$ complexity with three tricks, each by $O(n)$: linear view change, threshold signatures, and verifiable random functions. All three are known, i.e., the solutions are right in front of our eyes, and yet LinBFT is the first $O(n)$ solution with deterministic security guarantees. Further, LinBFT also addresses issues that are specific to permission-less, public blockchain systems, such as anonymous participants without a public-key infrastructure, proof-of-stake with slashing, rotating leader, and a dynamic participant set. In addition, LinBFT contains no proof-of-work module, reaches consensus for every block, and tolerates changing honesty of the participants for different blocks.
Regio A. Michelin, Ali Dorri, Roben Castagna Lunardi, Marco Steger · 7 authors
There is increased interest in smart vehicles acting as both data consumers and producers in smart cities. Vehicles can use smart city data for decision-making, such as dynamic routing based on traffic conditions. Moreover, the multitude of embedded sensors in vehicles can collectively produce a rich data set of the urban landscape that can be used to provide a range of services. Key to the success of this vision is a scalable and private architecture for trusted data sharing. This paper proposes a framework called SpeedyChain, that leverages blockchain technology to allow smart vehicles to share their data while maintaining privacy, integrity, resilience and non-repudiation in a decentralized, and tamper-resistant manner. Differently from traditional blockchain usage (e.g., Bitcoin and Ethereum), the proposed framework uses a blockchain design that decouples the data stored in the transactions from the block header, thus allowing for fast addition of data to the blocks. Furthermore, an expiration time for each block to avoid large sized blocks is proposed. This paper also presents an evaluation of the proposed framework in a network emulator to demonstrate its benefits.
Blockchain and Cryptocurrencies are gaining unprecedented popularity and understanding. Meanwhile, Ethereum is gaining a significant popularity in the blockchain community, mainly due to the fact that it is designed in a way that enables developers to write smart contract and decentralized applications (Dapps). This new paradigm of applications opens the door to many possibilities and opportunities. However, the security of Ethereum smart contracts has not received much attention; several Ethereum smart contracts malfunctioning have recently been reported. Unlike many previous works that have applied static and dynamic analyses to find bugs in smart contracts, we do not attempt to define and extract any features; instead we focus on reducing the expert's labor costs. We first present a new in-depth analysis of potential attacks methodology and then translate the bytecode of solidity into RGB color code. After that, we transform them to a fixed-sized encoded image. Finally, the encoded image is fed to convolutional neural network (CNN) for automatic feature extraction and learning, detecting compiler bugs of Ethereum smart contract.
With their innovative and fundamentally liberalising approach to data storage, distributive ledger technologies (DLTs) like blockchain—and other associated technologies offer immense benefits to both the public and private sectors, not least in terms of upping efficiency. Lovers of freedom should also note, however, that they offer an important chance to empower individuals in their necessary engagements with the state, and to rebuild societal trust for the common good. In this paper, we propose the establishment of a UK-based international blockchain competition, and a public-facing **‘Chief Blockchain Officer.’** We also propose a UK **‘blockchain departmental target’**: a long-term aim for government departments to make a 1% efficiency saving by embracing blockchain and other associated innovative technologies. A renewed UK focus on efficiency and the opportunities of new technology would be inspirational, and we look forward to discussing these proposals, and carrying out further research into Distributed Ledger Technologies.
This article evaluates the legal framework of cryptocurrency in various countries. The new currency instrument is abstract currencies. They are currencies in the sense that they can be exchanged peer-to-peer. They are representations of numbers, i.e. abstract objects. An abstract currency system is a self-enforcing system of property rights over an abstract instrument which gives its owners the freedom to use and the right to exclude others from using the instrument. Cryptocurrency or virtual currency is a cryptographically protected, decentralized digital currency used as a means of exchange. Due to the development of new technologies and innovations, the rate of use of virtual currency is rapidly increasing throughout the globe, replacing not only cash payments and payments by bank transfer, but also electronic cash payments. Among the best-known representatives of cryptocurrencies are Bitcoin, Litecoin and Ethereum. Legal scholars have not yet reached a consensus regarding the nature and legal status of virtual currency. Virtual currency possesses the nature of obligations righ ts as well as property rights, since it may be both a means of payment and a commodity. Depending on the country, the approach to cryptocurrencies may be different. Today there is already an international cryptocurrency community that does not have a single coordinating center. Only progressive jurisdiction and state regulation of cryptocurrency activity will allow the creation of the conditions that will ensure the implementation of legitimate and safe cryptocurrency relations.
Maged N. Kamel Boulos, James T. Wilson, Kevin A. Clauson
A PubMed query run in June 2018 using the keyword 'blockchain' retrieved 40 indexed papers, a reflection of the growing interest in blockchain among the medical and healthcare research and practice communities. Blockchain's foundations of decentralisation, cryptographic security and immutability make it a strong contender in reshaping the healthcare landscape worldwide. Blockchain solutions are currently being explored for: (1) securing patient and provider identities; (2) managing pharmaceutical and medical device supply chains; (3) clinical research and data monetisation; (4) medical fraud detection; (5) public health surveillance; (6) enabling truly public and open geo-tagged data; (7) powering many Internet of Things-connected autonomous devices, wearables, drones and vehicles, via the distributed peer-to-peer apps they run, to deliver the full vision of smart healthy cities and regions; and (8) blockchain-enabled augmented reality in crisis mapping and recovery scenarios, including mechanisms for validating, crediting and rewarding crowdsourced geo-tagged data, among other emerging use cases. Geospatially-enabled blockchain solutions exist today that use a crypto-spatial coordinate system to add an immutable spatial context that regular blockchains lack. These geospatial blockchains do not just record an entry's specific time, but also require and validate its associated proof of location, allowing accurate spatiotemporal mapping of physical world events. Blockchain and distributed ledger technology face similar challenges as any other technology threatening to disintermediate legacy processes and commercial interests, namely the challenges of blockchain interoperability, security and privacy, as well as the need to find suitable and sustainable business models of implementation. Nevertheless, we expect blockchain technologies to get increasingly powerful and robust, as they become coupled with artificial intelligence (AI) in various real-word healthcare solutions involving AI-mediated data exchange on blockchains.
Decentralized Ledger Technology, popularized by the Bitcoin network, aims to keep track of a ledger of valid transactions between agents of a virtual economy without a central institution for coordination. In order to keep track of a faithful and accurate list of transactions, the ledger is broadcast and replicated across machines in a peer-to-peer network. To enforce validity of transactions in the ledger (i.e., no negative balance or double spending), the network as a whole coordinates to accept or reject new transactions based on a set of rules aiming to detect and block operations of malicious agents (i.e., Byzantine attacks). Consensus protocols are particularly important to coordinate operation of the network, since they are used to reconcile potentially conflicting versions of the ledger. Regardless of architecture and consensus mechanism used, resulting economic networks remain largely similar, with economic agents driven by incentives under a set of rules. Due to the intense activity in this area, proper mathematical frameworks to model and analyze behavior of blockchain-enabled systems are essential. In this paper, we address this need and provide the following contributions: (i) we establish a formal framework, with tools from dynamical systems theory, to mathematically describe core concepts in blockchain-enabled networks, (ii) we apply this framework to the Bitcoin network and recover its key properties, and (iii) we connect our modeling framework with powerful tools from control engineering, such as Lyapunov-like functions, to properly engineer economic systems with provable properties. Apart from the aforementioned contributions, the mathematical framework herein proposed lays a foundation for engineering more general economic systems built on emerging Turing complete networks, such as the Ethereum network, through which complex alternative economic models are explored.
This paper examines how circular economics addresses and uses smart technology, and demonstrates the lack of consideration given to ownership issues in such contexts. The extent to which circular economic ideals require controlling goods down-stream will be exposed. Following this is an analysis of the ramifications of smart technology, illustrated with recent examples of control through smart technology. This leads to a critique of the US Supreme Court’s recent decision on patent exhaustion Impression Products v Lexmark alongside the CJEU’s decision in UsedSoft on copyright, addressing implications for contracting practices. The article concludes by urging close comparison of claimed benefits arising from circular economic approaches to smart technology with the potential costs of control (or lack thereof) of novel technologies.
By transforming the Zeta function into a real function through Laplace inverse transformation, an algebraic research paradigm for prime number distribution was established, and important results were obtained (page 10). This method has received positive feedback from Sir Atiyah (see page 14 for details) and demonstrates significant potential for applications in the field of cryptography and blockchain. Core breakthrough: Revealing the essence of Zeta function, replacing complex analysis with convolutional algebra, making the proof path of Riemann hypothesis clear, concise, and computable.
Objective: to consider the features of centralized and decentralized monetary systems development and to identify the necessary conditions for the transition of the national economy to decentralized network platforms operating within the distributed ledger technology, public and private digital currencies.Methods: a systemic approach to the cognition of economic phenomena, enabling to study them in dynamic development, taking into account the influence of various environmental factors. The systemic approach determined the choice of specific research methods: empirical, historical, logical, comparative and statistical.Results: the article considers different approaches to the organization of money issue. It is shown that the era of the centralized monetary system, based on the issue of Central banks, has come to its end. The Central bank is the main link of the centralized monetary system, while in the context of 2008 financial crisis the functions of the Central Bank as the lender of last resort were significantly expanded by changing the paradigm of the monetary mechanism. It is established that the new monetary mechanism has become the main channel of money supply in the economy, while the main factors of the new monetary supply formation are the reserve money of Central banks, new Basel standards and high requirements for borrowers. This monetary policy and the centralization of the financial market have led to a distortion of the market pricing mechanism in the monetary market and to the disruption of competition in the financial intermediation market. The author analyzes the new trends in the emergence of a decentralized monetary system in the world economy based on public and private digital currencies issued by users of distribution computer networks. The article shows the mechanism and technology of crypto currency emission, which implies the use of public or private blockchain without any participation of the Central bank and other financial intermediation institutions.Scientific novelty: for the first time, the article shows that the era of centralized monetary system based on monopoly issue by Central banks, has come to its logical end; a decentralized monetary system is emerging in the world economy today, based on public and private issue of digital currency; in the course of legalization, growth of scalability, confidentiality, validation and tokenization of real assets, the crypto currencies will become a liquid and less volatile monetary asset.Practical significance: the main provisions and conclusions of the article can be used to clarify the target mandates, tools, channels and mechanisms of monetary policy of the Bank of Russia, capable of launching a decentralized crypto currency market, acting as a built-in stabilizer of financial sustainability and elastic regulation of trade and financial imbalances within the country and between countries.
Amaç: Kripto parabirimleri teknolojinin gelişmesiyle birlikte son yıllarda önem kazanmış ve dahaçok kullanılır hale gelmiştir. Merkezi bir otoriteye bağlı olmayan vekriptografik sistemler ile güvenliği sağlanan bu para birimlerinden en bilineniBitcoin’dir. Bu çalışmada, başlıca kripto para birimleri ve işleyiş süreçleriincelenmiştir. Buna ek olarak Bitcoin’in döviz, hisse senedi emtia piyasalarıve faiz ile olan ilişkisi ele alınmıştır. Yöntem: Çalışmadakullanılan veri setinin frekansı aylık olup Mart-2012 ile Mayıs-2018 döneminikapsamaktadır. Zaman serisi yöntemlerinden Johansen Eşbütünleşme ve GrangerNedensellik analizleri uygulanmıştır.Bulgular: Çalışmanınsonuçlarına göre, Bitcoin fiyatlarının artan bir trende ve yüksek birvolatiliteye sahip olduğu görülmektedir. Faiz değişkeni ile Bitcoin fiyatları arasında diğer analizler ve Grangernedensellik testi sonuçlarına göre istatistiksel olarak anlamlı bir ilişkivardır.
Este artigo elucida aspectos jurídicos e regulatórios do bitcoin (BTC) com objetivo de reduzir a insegurança jurídica em que se encontram as operações realizadas com a criptomoeda no Brasil. Essa pesquisa descritiva de cunho qualitativo e método dedutivo averigua, por meio do estudo da legislação e doutrinas pertinentes, a quais órgãos reguladores do Sistema Financeiro Nacional (SFN) as operações com o BTC estão submetidas. Para tanto, são introduzidas as funcionalidades, potencialidades e limitações do blockchain, tecnologia subjacente à criptomoeda. Após, são destacados aspectos relevantes do Sistema Financeiro Nacional. Em seguida, busca-se classificação conceitual jurídica adequada ao Bitcoin. Findas essas etapas, o trabalho sugere que, em razão da natureza jurídica do bitcoin como bem intangível, no atual aparato legal, não há previsão regulatória sobre o BTC, motivo pelo qual, no momento, operações com a moeda virtual não estão submetidas a qualquer órgão do SFN.
Currently, blockchain technology, which is decentralized and may provide tamper-resistance to recorded data, is experiencing exponential growth in industry and research. In this paper, we propose the MIStore, a blockchain-based medical insurance storage system. Due to blockchain's the property of tamper-resistance, MIStore may provide a high-credibility to users. In a basic instance of the system, there are a hospital, patient, insurance company and n servers. Specifically, the hospital performs a (t, n)-threshold MIStore protocol among the n servers. For the protocol, any node of the blockchain may join the protocol to be a server if the node and the hospital wish. Patient's spending data is stored by the hospital in the blockchain and is protected by the n servers. Any t servers may help the insurance company to obtain a sum of a part of the patient's spending data, which servers can perform homomorphic computations on. However, the n servers cannot learn anything from the patient's spending data, which recorded in the blockchain, forever as long as more than n - t servers are honest. Besides, because most of verifications are performed by record-nodes and all related data is stored at the blockchain, thus the insurance company, servers and the hospital only need small memory and CPU. Finally, we deploy the MIStore on the Ethererum blockchain and give the corresponding performance evaluation.
Nowadays many applications have employed the blockchain technology from sam- ple cryptocurrency to smart contracts applications. Bitcoin is one of the cryp- tocurrency application and digital payment system. It is considered as the first decentralized digital currency system. It was invented by unidentified person or group under the name of Satoshi Nakamoto in 2009 (Nakamoto, 2008). The most three features should be achieved by Bitcoin are decentralized, users anonymity, and consensus. In order to achieve these vital features the Bitcoin system should be provably secure against the attacks. Many attacks have been proposed to change unfairly the reward system of the mining pool and allow the malicious miners to earn undue wage. Selfish Attack, Block Withholding (BWH) Attack and Fork- ing After Withholding (FAW) Attack are three attacks which abusing the reward system and letting the infiltration miners to receive un unearned profits and as a sequence this will affect the decentralized feature of the Bitcoin system. Some studies proposed a solution for Selfish Attack and Block Withholding attack such (Eyal and Sirer, 2014b) and (Bag et al., 2017). FAW attack is first introduced by (Kwon et al., 2017) where this attack combines two attacks: Selfish and BWH attacks. In order to come up with a solution for FAW attack (Kwon et al., 2017) propose partial countermeasures for preventing their FAW attack. However, their solution is neither perfect nor practical. Therefore this study addresses this attack and analyzes its strategy then come up with a prevention solution. The result of this study shows that our prevention solution is practical and more effcient.
In order to solve the problem of illegal member’s tracking attack, which caused by the vehicle units’ privacy disclosure in vehicular ad hoc networks (VANETs), a vehicle identity authentication protocol based on lightweight group signature was proposed by analysis of topology and communication characteristics of VANETs in this paper, which can authenticate the vehicles anonymously in a fast and efficient way. The protocol has five stages. In the initialization phase, the public/private key pairs and system parameters of the group were generated by the VANETs system, then the group public key and system parameters were distributed to the on-board units by the roadside auxiliary facilities. The group private key was kept by the group manager. When a vehicle unit entered VANETs, the unit’s own identity was submitted to the group manager by the blind signature. A group certificate would be distributed to the vehicle unit by the group manager when authentication passed. In the cooperative communication stage, the vehicle member who owned the group certificates signed the state information with the valid certificate and group public key, then sent it to the nearby vehicle units by the car sensors, and achieved cooperative driving with surrounding vehicles. In the message verification stage, only can the legal vehicle members open the received status information by using group public key, but couldn’t know the true identity of the message sender. In this way, the anonymous communication among vehicles was realized. In the stage of signature verification, when a vehicle unit broadcasted a false message for the purpose of exclusively using road resource and caused traffic accident, the group manager can open the signature of the message by using the group private key, and traversed the corresponding vehicle members to carry on the accountability. The innovation of the paper was the usage of improved lightweight group signature technology, which could ensure that the length of group public key and group signature didn’t depend on the number of group members. Zero knowledge proof was also used as a means of membership authentication which improved the speed of authentication among the members. The security of the protocol was analyzed and proved mathematically in this paper, and a LAN simulation platform composed of 100 PC machines was built to simulate the cooperative communication among vehicle units in VANETs. The experimental results showed that authentication time of the protocol was about 7 ms among 100 vehicle users. The performance of the proposed protocol is superior to the contrasted schemes. It greatly reduced the storage and calculation burden of the vehicle units during the process of identity authentication.
(eng) The main conceptual element this thesis orbits around is the idea of using social networks as a data source. First, classical trading theory and current usage of data obtained from social networks is reviewed. Taking all this information into account, a forecasting of the Bitcoin price is performed using both classical methods and machine learning Neural Networks. In order to obtain data from social networks, another complexity layer needs to be added by accessing the sources through APIs and directly web-scrapping the net. The results of all of this complex implementation are given with a strong focus on visualisation using several different techniques. Finally, after a critical discussion a Future Work chapter is introduced, where many possible follow-ups are drawn up.
Juan Carlos Farah, Andrii Vozniuk, María Jesús Rodríguez‐Triana, Denis Gillet
The need to ensure privacy and data protection in educational contexts is driving a shift towards new ways of securing and managing learning records. Although there are platforms available to store educational activity traces outside of a central repository, no solution currently guarantees that these traces are authentic when they are retrieved for review. This paper presents a blueprint for an architecture that employs blockchain technology to sign and validate learning traces, allowing them to be stored in a distributed network of repositories without diminishing their authenticity. Our proposal puts participants in online learning activities at the center of the design process, granting them the option to store learning traces in a location of their choice. Using smart contracts, stakeholders can retrieve the data, securely share it with third parties and ensure it has not been tampered with, providing a more transparent and reliable source for learning analytics. Nonetheless, a preliminary evaluation found that only 56% of teachers surveyed considered tamper-evident storage a useful feature of a learning trace repository. These results motivate further examination with other end users, such as learning analytics researchers, who may have stricter expectations of authenticity for data used in their practice.
Objectives Smart e-Forms are a new form of technology that converts complex paperwork to digital forms in an enterprise setting. In the context of the rapidly changing communication channels brought by the move toward a digital innovation environment in the financial industry, this paper examines a smart e-Form solution that can aid effective business communication. Methods Financial services using smart e-Forms are developing multilaterally with the use of electronic documents in both face-to-face and non-face-to-face channels. The electronic document system for enhancing competitiveness in face-to-face environments includes PPR (paperless and process reconstruction) and tablet banking systems, while the distance contract system through mobile banking can be utilized in non-face-to-face environments. Results As a functional document format that includes business logic, smart e-Forms allow various types of data input such as photos, voice recordings, barcode scanning, and e-Signatures through the use of smart devices. This technology has been utilized in implementing paperless services, tablet banking, and distance contract systems for a number of financial institutions, and e-Form technology is being optimized for the latest mobile devices in response to the demands of the financial market. Conclusions The rapid development of smart e-Form technology has played a major role in innovation in the financial sector. This technology improves customer convenience and work efficiency for a diversified financial environment, and the e-Form-based financial service system is becoming more competitive in various ways to lead the Fourth Industrial Revolution.
Long Finance's Eternal Coin research programme has produced this report entitled “On-line Simulation For Cryptocurrencies: Risk Control Framework”.
Cryptocurrency development has been an exciting area for several years, with many new ideas coming forward and still the potential of a new launch that solves the biggest technical and commercial challenges. However, to date, almost all the 1,500+ cryptocurrencies that have been launched have died away, and even Bitcoin has serious technical limitations that have prevented it from being a competitive payment system in most situations. Cryptocurrencies have been seriously impacted by technical problems, disagreements, fraud, hacks, competition, regulation, lack of popularity, apathy, and sheer incompetence.
To increase the odds of success, those who aspire to a successful cryptocurrency need to think through the challenges they may face, make plans, make design choices, and develop capabilities that help them survive. They need control frameworks, practices, and procedures to create business value and minimize risk. While boring, intellectually these are tough and need to respond to the special characteristics of cryptocurrencies. This report looks at the control needs of cryptocurrencies mainly from the perspective of their creators and regulators (such as they are so far). The objective is to make recommendations on controls for cryptocurrencies that are not too prescriptive, but more helpful than generic control frameworks such as COSO’s frameworks for internal control and enterprise risk management (Committee of Sponsoring Organizations of the Treadway Commission 2013, 2017), and variations on them (e.g. Basel Committee on Banking Regulation 1998, Financial Reporting Council 2014).
This initial report complements previous Long Finance work on governance, audit, and standards for smart ledger systems. It also reflects the focus of the Eternal Coin research programme, a global discussion on the nature of money and the concept of value over the long term.”