Various technologies are mentioned in the 4th Industrial Revolution. One of the emerging issues in the power market is the blockchain-based smart grid network. We propose the architecture of the network by incorporating blockchain technology into the existing smart grid system. The Ethereum and Hyperledger Fabrics are widely used in the blockchain technology as public blockchains and private blockchains, respectively. We describe the network architecture in the smart grid blockchain and compare the performance of transactions processing. The performance analysis shows that Hyperledger Fabric is viable approach by providing pipelined concurrent transaction among peers processing and MVCC(multi-version concurrency control).
Ferdınando Chıacchıo, Lucio Compagno, Diego D’Urso, Luca Velardita · 5 authors
With the growth of a global market, new regulations aiming at preventing the fraud of counterfeiting drugs have been released all over the world. In the pharma industry, an innovative technology named serialization is becoming more and more popular as it allows to implement a packaging process based on a hierarchical aggregation. This guarantees that each box entering in the distribution network is marked with a unique identifier for an easy traceability by a central regulatory in charge to follow the life cycle of the product until given to the final patient. In this scenario, the blockchain might offer a breakthrough proposing a decentralized and immutable traceability mechanism able to increase the security of the data and to reduce the success of a fraud attempt. To demonstrate the effectiveness of this technology, in this paper, a DAPP based on the Ethereum blockchain has been coded and tested as prototype in a pharma industry.
Open access
Blockchain Technology Applications and Security
Innovative Microfluidic and Catalytic Techniques Innovation
Physical Unclonable Functions (PUFs) and Hardware Security
espanolLa aparicion de la Cadena de Bloques ha permitido la automatizacion en la creacion del dinero, asi como la posibilidad de prescindir de terceros de confianza. La incorporacion de los contratos inteligentes en las red Ethereum ha hecho posible dar un paso mas alla, la creacion de Organizaciones Autonomas Descentralizadas (DAOs), a saber, el paso de un contrato inteligente en el que las prestaciones se cumplen con independencia de la voluntad de las partes contratantes, a un estatuto inteligente en el que la organizacion y funcionamiento de la sociedad se hace de manera automatica prescindiendo de Administradores y permitiendo que la voluntad del conjunto se cumpla sin intermediarios. Ello plantea cuestiones juridicas, como su naturaleza juridica, su personalidad juridica, la posibilidad de que se cometan delitos a traves de las mismas y que pena corresponderia, la imposibilidad de imponerles el cumplimiento la ley, la ausencia de una sede fisica, la dificultad de embargas activos y en definitiva la dificultad de determinar la jurisdiccion aplicable. Para ello, se realiza un analisis juridico exhaustivo de esta nueva figura del trafico mercantil y se hacen propuestas para la resolucion de las distintas problematicas. EnglishThe appearance of the Blockchain has allowed automation in the creation of money, as well as the possibility of dispensing trusted third parties. The incorporation of smart contracts in the Ethereum network has made it possible to go one step further, the creation of Decentralized Autonomous Organizations (DAOs), namely the step of a smart contract in which the benefits are fulfilled regardless of the will of the contracting parties, to an intelligent statute in which the organization and operation of the company is done automatically without administering and allowing the will of the whole to be fulfilled without intermediaries. This situation raises legal issues, such as their legal nature, their legal status, the possibility of crimes being committed through them and what penalty would be applied, the impossibility of imposing compliance with the law, the absence of a physical headquarters, the difficulty of active seizures and ultimately the difficulty of determining the applicable jurisdiction. For this, an exhaustive legal analysis of this new figure of commercial traffic is carried out and proposals are made for the resolution of the different problems.
Finansal zaman serilerinde görülen değişen varyans sorununun (ARCH etkisi) sonucu olarak otoregresif koşullu değişen varyans modelleri bulunmuştur. Çalışmamızda, piyasa değeri en yüksek üç kripto paranın [Bitcoin (BTC), Ethereum (ETH) ve Ripple (XRP)] getirileri incelenmiş ve söz konusu getirilerde finansal zaman serilerine benzer şekilde ARCH etkisi bulunmuştur. Söz konusu üç kripto paranın volatiliteleri için en iyi modelin hesaplanmasında altı GARCH modelini karşılaştırılmıştır. Bu modeller sırasıyla GARCH (1,1), EGARCH (1,1), TGARCH (1,1), APARCH (1,1), CGARCH (1,1) ve ACGARCH (1,1) modellerinden oluşmaktadır. Çalışma kapsamında 01.10.2015 - 01.10.2018 tarihleri arasında Bitcoin (BTC), Ethereum (ETH) ve Ripple (XRP) kripto paralarının günlük kapanış verilerinden elde edilen getiriler kullanılmıştır. Volatilite tahminlerinde Bitcoin (BTC) ve Ethereum (ETH) için en iyi model EGARCH (1,1), Ripple (XRP) için ise APARCH (1,1) modeli bulunmuştur. Çalışma kapsamında bu modeller kullanılarak volatiliteler üzerinde negatif şokların pozitif şoklardan daha fazla etkisinin bulunduğunu gösteren kaldıraç etkisi incelenmiştir. Bitcoin (BTC) ve Ethereum (ETH) modellerinde kaldıraç etkisi bulunmamış, bununla birlikte pozitif şoklar negatif şoklara göre daha fazla volatiliteye neden olmuştur. Ancak, Ripple (XRP) volatilite modelinde kaldıraç etkisi belirlenmiştir.
Classified protection is one of primary security policies of information system in many countries. With the increasing popularity of blockchain in various fields of applications, it is extremely necessary to promote classified protection for blockchain's risk assessment in order to push forward the sustainable development of blockchain. Taking the Level 3 in Chinese classified protection 2.0 as an example, this paper proposes the common evaluation rules on blockchain to ensure that blockchain can meet the needs of countries to build it as critical infrastructure. Both assessment requirements and enforcement proposals are presented and analyzed from the standpoint of blockchain's core technologies, e.g., peer-to-peer network, distributed ledger, contract's scripting system, and consensus mechanism. Moreover, the assessment results on three main platforms, Bitcoin, Ethereum, and Hyperledger, are summarized and analyzed in compliance with the control points specified in the level 3. Our investigation indicates that the current blockchain is able to satisfy the requirements of evaluation items in many aspects, such as software fault tolerance, resource control, backup and recovery, but further improvements are still needed for some aspects, including security audit, access control, identification and authentication, data integrity, etc., in order to satisfy the requirements of important fields on national security, economic development and human life.
Cryptocurrencies (e.g., Bitcoin and Ethereum), which promise to become the future of money transactions, are mainly implemented with blockchain technology. However, blockchain suffers from scalability issues. Sharding is the leading solution for blockchain scalability. Sharding splits the blockchain network into sub-chains called shards/committees. Each shard processes a sub-set of transactions, rather than the entire network processing all transactions. This raises security issues for sharding-based blockchain protocols. In this paper, we propose a novel methodology to analyze the security of these protocols (e.g., OmniLedger and RapidChain). In particular, this methodology estimates the failure probability of one sharding round taking into consideration the failure probabilities of all shards. To illustrate the effectiveness of the estimated failure probability, we conduct a numerical analysis of our methodology based on a huge number of trials. Finally, we compute confidence intervals to accurately estimate the failure probability and compare our methodology with existing approaches.
Since it was invented by Satoshi Nakamoto in 2008, Bitcoin has drawn considerable attention both from the financial industry and government supervisory departments, and there is no unanimity on Bitcoin’s nature in the academic field. Some people may think Bitcoin is more like an asset than a currency. And investors’ motivations for incorporating Bitcoin into their portfolios may vary. Might there be a better way to deal with the risk-detection issue associated with such a unique and ambiguous object? The copula-GARCH method has been proven in much of the literature to be a better way than the traditional ways to estimate the value at risk (VaR) of portfolios. When it comes to a portfolio containing Bitcoin, can it still maintain its superiority? In this study, gold and Ethereum were each used to construct a portfolio with Bitcoin. We collected a total of 2,246 daily adjusted closing prices from July 23, 2010, to March 12, 2019. As for the copula-GARCH model, we selected four constant and two time-varying copula models combined with GARCH Student-t residuals to fit the joint distribution of the two assets in the portfolios. The traditional methods refer to the historical simulation, the variance-covariance method, the EWMA method, and the univariate GARCH VaR method. We adopted each method to compute corresponding one-day VaRs. Our results indicated that for the portfolios containing Bitcoin and Ethereum, the copula-GARCH method performed better than traditional methods, while for the portfolio consisting of Bitcoin and gold, traditional methods performed better. Our results may suggest that the copula-GARCH method may not be suitable in the extremely low correlation case.
Machine learning has recently enabled large advances in artificial intelligence, but these results can be highly centralized. The large datasets required are generally proprietary; predictions are often sold on a per-query basis; and published models can quickly become out of date without effort to acquire more data and maintain them. Published proposals to provide models and data for free for certain tasks include Microsoft Research's Decentralized and Collaborative AI on Blockchain. The framework allows participants to collaboratively build a dataset and use smart contracts to share a continuously updated model on a public blockchain. The initial proposal gave an overview of the framework omitting many details of the models used and the incentive mechanisms in real world scenarios. In this work, we evaluate the use of several models and configurations in order to propose best practices when using the Self-Assessment incentive mechanism so that models can remain accurate and well-intended participants that submit correct data have the chance to profit. We have analyzed simulations for each of three models: Perceptron, Naïve Bayes, and a Nearest Centroid Classifier, with three different datasets: predicting a sport with user activity from Endomondo, sentiment analysis on movie reviews from IMDB, and determining if a news article is fake. We compare several factors for each dataset when models are hosted in smart contracts on a public blockchain: their accuracy over time, balances of a good and bad user, and transaction costs (or gas) for deploying, updating, collecting refunds, and collecting rewards. A free and open source implementation for the Ethereum blockchain and simulations written in Python is provided at https://github.com/microsoft/0xDeCA10B. This version has updated gas costs using newer optimizations written after the original publication.
Crowdsourcing is a process wherein an individual or an organisation utilizes the talent pool present over the Internet to accomplish their task. The existing crowdsourcing platforms and their reputation computation are centralised and hence prone to various attacks or malicious manipulation of the data by the central entity. A few distributed crowdsourcing platforms have been proposed but they lack a robust reputation mechanism. So we propose a decentralised crowdsourcing platform having an immutable reputation mechanism to tackle these problems. It is built on top of Ethereum network and does not require the user to trust a third party for a non malicious experience. It also utilizes IOTAs consensus mechanism which reduces the cost for task evaluation significantly.
Abstract Solidity is the dominant programming language for Ethereum smart contracts. This paper presents a high-level formalization of the Solidity language with a focus on the memory model. The presented formalization covers all features of the language related to managing state and memory. In addition, the formalization we provide is effective: all but few features can be encoded in the quantifier-free fragment of standard SMT theories. This enables precise and efficient reasoning about the state of smart contracts written in Solidity. The formalization is implemented in the SOLC-VERIFY verifier and we provide an extensive set of tests that covers the breadth of the required semantics. We also provide an evaluation on the test set that validates the semantics and shows the novelty of the approach compared to other Solidity-level contract analysis tools.
Utz Nisslmueller, Klaus-Tycho Foerster, Stefan Schmid, Christian Decker
Cryptocurrency off-chain networks such as Lightning (e.g., Bitcoin) or Raiden (e.g., Ethereum) aim to increase the scalability of traditional on-chain transactions. To support nodes in learning about possible paths to route their transactions, these networks need to provide gossip and probing mechanisms. This paper explores whether these mechanisms may be exploited to infer sensitive information about the flow of transactions, and eventually harm privacy. In particular, we identify two threats, related to an active and a passive adversary. The first is a probing attack: here the adversary aims to detect the maximum amount which is transferable in a given direction over a target channel by actively probing it and differentiating the response messages it receives. The second is a timing attack: the adversary discovers how close the destination of a routed payment actually is, by acting as a passive man-in-the middle and analyzing the time deltas between sent messages and their corresponding responses. We then analyze the limitations of these attacks and propose remediations for scenarios in which they are able to produce accurate results.
Smart contracts are computer programs that are deployed on the blockchain and can then be executed. Fees in form of gas have to be paid for deploying a smart contract on the blockchain, depending on the size of the byte code. Additional fees have to be paid, whenever a function of a smart contract is executed, depending on the needed computational steps and required storage space. On the Ethereum blockchain, millions of USD are paid in form of gas fees every single day. Since gas cost can increase if a contract is not well-implemented, there is a lot of incentive to reduce these gas cost in order to save money. We identified 19 optimization strategies from the field of software engineering, which can be applied to Solidity smart contracts in order to reduce the required gas cost. To show how these rules can be used to optimize smart contracts, we developed a prototype. The prototype detects rule violations from 9 of these rules and in addition automatically optimizes 6 of them. The prototype analyzed 3,018 verified open source smart contracts from etherscan.io. We found 471 rule violations in our test data set spread across 204 different contract files. That means, roundabout 6.8% of the data set violated at least one of the rules. We deployed the automatically optimized contracts in a test environment before and after the optimization, to compare the gas usage. We were on average able to save 1,213 gas for deploying an optimized contract version compared to the initial one. For calling an optimized function once, we were able to save on average 123 gas, compared to the initial function call.
Energy supply industries play a vital role in a country. Inefficiencies in the energy supply chain regarding tricky contests and the lack of management instantly change energy tariff calculation. This work proposes the Ethereum blockchain platform with existing traditional infrastructure to track and investigate energy supply chain activities using a unique identity with smart contracts. It maintains the records of the organization's protected and available actions to stakeholders according to the recognized collection of procedures and practices without requiring any centralized administration. The purpose of the study is to focus entirely on analyzing and developing a simplified, low-cost, and secure decentralized application (DApp) in the untrusted environment. It should be fit to quickly connect the present energy supply industry at various geological locations to track and trace the energy market's linked data. Keywords: Blockchain, smart contract, energy supply chain, decentralization, design science.
Subscriber authentication is a primitive operation in mobile networks required by each operator prior to offering any service to end users. In this paper, we propose a novel blockchain-based Authentication and Key Agreement (AKA) protocol for roaming services in 5G networks. Each Home Network (HN) creates its own smart contract and publishes its address to inform other operators who want to offer roaming services to HN subscribers. All subsequent communication between the HN and Serving Network (SN) is done by calling the function of this smart contract. The proposed protocol eliminates the need for a secure channel between the HN and SN, which is a primary requirement of current 5G AKA protocols. In practice, a secure channel requires the HN and SN to establish a secure session before running the AKA protocol. Further, the proposed protocol leverages the benefits of blockchain, such as auditable log, decentralized architecture, and the prevention of Denial of Service (DoS) attacks. Furthermore, we provide a security proof of the protocol through formal verification using ProVerif. The results show that our scheme tends to preserve user privacy and at the same time provides mutual authentication of the participants. Finally, our evaluation of the Ethereum blockchain shows that the protocol is efficient in terms of both transaction and execution costs.
The global implementation architecture of the traditional stock market distributes responsibilities and data across different intermediaries, including financial and governmental organizations. Each organization manages its system and collaborates with the others to facilitate trading on the stock exchange platform, and typically buy-sell orders go through different parties before settlement. This design architecture that involves a complex chain of intermediaries has several limitations and shortcomings, such as a single point of failure, a longer time for financial settlements, and weak transparency. Blockchain technology consists of a network of computer nodes that securely share a common ledger without the need of having any kind of intermediaries. In this paper, we present a novel blockchain-based architecture for a fully decentralized stock market. Our architecture is based on a private Ethereum blockchain to create a consortium network leveraging organizations that are already involved in the traditional stock exchange to act as validating nodes. In our architecture, the stock exchange trading logic is completely implemented on a smart contract, while considering the existing governmental market regulations. Since the new platform does not introduce significant changes to the stock exchange trading logic and does not eliminate any of the traditional parties from the system, our proposal promotes efficient adoption and deployment of decentralized stock exchange platforms. In addition, we present a proof of concept implementation of the new architecture, including the smart contract for trade exchange, as well as a virtualization-based test network to assess the platform performance. The test network consists of virtual nodes that run the developed stock exchange smart contract where we measure the buy-sell orders throughput and latency under different network sizes and trading workload scenarios. The obtained results have shown that the proposed trading platform can reach a throughput of 311.8 tx/sec, which is equivalent to 89% of the optimal throughput when the sending rate is 350 tx/sec. This throughput is largely sufficient to meet the requirement of major stock exchanges, such as Singapore stock market.
Die Blockchain Technologie hat das Potential die Wirtschaft im Zeitalter der Digitalisierung zu revolutionieren. In zentralisierten Organisationen werden die Entscheidungen von einem Verantwortlichen oder einer Gruppe getroffen. In der Blockchain gibt es keinen bestimmten Entscheidungsträger. Um eine Entscheidung zu treffen, muss ein Konsens erreicht werden. Um diesen Konsens zu erreichen, wird von jeder Blockchain Plattform ein so genannter Konsens-Mechanismus eingesetzt. Damit Blockchains ihr volles ökonomisches Potential ausschöpfen können, muss eine gute Skalierbarkeit gegeben sein. Doch dazu müssen Kompromisse in anderen Bereichen eingegangen werden. Das Blockchain-Trilemma besagt, dass man die drei Haupteigenschaften Skalierbarkeit, Sicherheit und Dezentralität immer zulasten der anderen erreicht, bzw. dass alle drei Eigenschaften nicht gleichzeitig maximiert werden können. Die implementierten Konsens-Mechanismen versuchen dieses Dilemma mit unterschiedlichen Ansätzen zu lösen. Daher sind sie einer der wichtigsten Aspekte sowie Unterscheidungsmerkmale der Blockchain Plattformen. Diese Arbeit bietet einen Überblick sowie eine technische Analyse über die zur Zeit existierenden Konsens-Mechanismen. Darüber hinaus werden Smart Contract Plattformen analysiert und die dort eingesetzten Konsens-Mechanismen detailliert beleuchtet. Außerdem wird die Umstellung des Konsens-Mechanismus von Proof of Work zu Proof of Stake in der Ethereum-Plattform anhand Ihres Einflusses auf zukünftige Smart Contracts analysiert. Die Analyse liefert einen Überblick über 62 Konsens-Mechanismen und 21 Smart Contract-Plattformen die im Moment eingesetzt werden. Weiter werden Kriterienkataloge vorgestellt, welche für den Vergleich von Smart Contract-Plattformen sowie deren Konsens-Mechanismen eingesetzt werden können.
Developing compiler optimizations, especially for new, rapidly evolving smart contract languages, can be onerous and error-prone, but is especially important for smart contracts, where deployment and execution directly translate to monetary cost and which cannot change once deployed. One common optimization technique is the use of peephole optimizations, replacement rules that are applied using pattern-matching. These rules are normally constructed using human expertise, which is both time-consuming and far from systematic in exploring opportunities for optimization. In this work we propose a pipeline to automatically populate the peephole optimizer of a smart contract compiler. We apply superoptimization to an existing code base to obtain sequences of instructions, which can be replaced by cheaper, observationally equivalent instructions. We then generate peephole optimization rules by extracting the underlying patterns of these optimizations. We provide a case study of our approach and a prototype implementation for bytecode of the Ethereum Virtual Machine, the tool ppltr, which combines the superoptimizer ebso and the rule generator sorg. Then we evaluate our approach by generating and applying nearly 1k peephole optimization rules extracted from 2k optimizations obtained from deployed bytecode.