Using blockchain technology, it is possible to create contracts that offer a reward in exchange for a trained machine learning model for a particular data set. This would allow users to train machine learning models for a reward in a trustless manner. The smart contract will use the blockchain to automatically validate the solution, so there would be no debate about whether the solution was correct or not. Users who submit the solutions won't have counterparty risk that they won't get paid for their work. Contracts can be created easily by anyone with a dataset, even programmatically by software agents. This creates a market where parties who are good at solving machine learning problems can directly monetize their skillset, and where any organization or software agent that has a problem to solve with AI can solicit solutions from all over the world. This will incentivize the creation of better machine learning models, and make AI more accessible to companies and software agents.
Bitcoin cryptocurrency has risen in popularity. Therefore, it not only attracts users to use it, but also it attracts the malware developers to attack it. While online Bitcoin wallets allow users to conveniently store and manage their bitcoins, they are vulnerable to several attacks.
Blockchain-based distributed computing platforms enable the trusted execution\nof computation - defined in the form of smart contracts - without trusted\nagents. Smart contracts are envisioned to have a variety of applications,\nranging from financial to IoT asset tracking. Unfortunately, the development of\nsmart contracts has proven to be extremely error prone. In practice, contracts\nare riddled with security vulnerabilities comprising a critical issue since\nbugs are by design non-fixable and contracts may handle financial assets of\nsignificant value. To facilitate the development of secure smart contracts, we\nhave created the FSolidM framework, which allows developers to define contracts\nas finite state machines (FSMs) with rigorous and clear semantics. FSolidM\nprovides an easy-to-use graphical editor for specifying FSMs, a code generator\nfor creating Ethereum smart contracts, and a set of plugins that developers may\nadd to their FSMs to enhance security and functionality.\n
Katiuscia Mannaro, Gavina Baralla, Andrea Pinna, Simona Ibba
The use of teledermatology in primary care has been shown to be reliable, offering the possibility of improving access to dermatological care by using telecommunication technologies to connect several medical centers and enable the exchange of information about skin conditions over long distances. This paper describes the main points of a teledermatology project that we have implemented to promote and facilitate the diagnosis of skin diseases and improve the quality of care for rural and remote areas. Moreover, we present a blockchain-based approach which aims to add new functionalities to an innovative teledermatology platform which we developed and tested in the Sardinian Region (Italy). These functionalities include giving the patient complete access to his/her medical records while maintaining security. Finally, the advantages that this new decentralized system can provide for patients and specialists are presented.
Since 2004, different research was handling the challenges in the centralized voting systems, e-voting protocols and recently the decentralized voting. So electronic voting puts forward some difficulties regarding the voter anonymity, the secure casting of the votes and to prevent the voting process from frauding. The Decentralized property of the technology called "blockchain" could have the solution for many of the challenges in voting research area and brings a new secure mechanism of safe and transparent voting. In this paper, a broad comparison between ongoing voting systems has studied by analyzing their structure and the drawbacks that should consider in future to improve the whole election process from keeping the privacy of the voter, casting a vote with the possibility to check if it was counted correctly to publishing the results. The result of the paper will give a new approach to extend the target of the election from small scale to large scale despite the fact of Ethereum limitation which can cast on the blockchain just five votes per minute. The primary challenge is to find an answer for this question: "How to balance between voter privacy and transparency without breaking the important rule where the voter can proof for a specific candidate that he voted for him in a bribe situation?".
Bitcoin is the first implementation of what has become known as a 'public permissionless' blockchain. Guaranteeing security and protocol conformity through its elegant combination of cryptographic assurances and game theoretic economic incentives, it permits censorship resistant public read-write access to its append-only blockchain database without the need for any mediating central authority. Not until its advent has such a trusted, transparent, comprehensive and granular data set of digital economic behaviours been available for public network analysis. In this article, by translating the cumbersome binary data structure of the Bitcoin blockchain into a high fidelity graph model, we demonstrate through various analyses the often overlooked social and econometric benefits of employing such a novel open data architecture. Specifically we show (a) how repeated patterns of transaction behaviours can be revealed to link user activity across the blockchain; (b) how newly mined bitcoin can be associated to demonstrate individual accumulations of wealth; (c) through application of the naive quantity theory of money that Bitcoin's disinflationary properties can be revealed and measured; and (d) how the user community can develop coordinated defences against repeated denial of service attacks on the network. All of the aforementioned being exemplary benefits that would be lost with the closed data models of the 'private permissioned' distributed ledger architectures that are dominating enterprise level development due to existing blockchain issues of governance, scalability and confidentiality.
Antonio Fernández Anta, Chryssis Georgiou, Kishori M. Konwar, Nicolas Nicolaou
Despite the hype about blockchains and distributed ledgers, no formal abstraction of these objects has been proposed. To face this issue, in this paper we provide a proper formulation of a distributed ledger object. In brief, we define a ledger object as a sequence of records, and we provide the operations and the properties that such an object should support. Implementation of a ledger object on top of multiple (possibly geographically dispersed) computing devices gives rise to the distributed ledger object. In contrast to the centralized object, distribution allows operations to be applied concurrently on the ledger, introducing challenges on the consistency of the ledger in each participant. We provide the definitions of three well known consistency guarantees in terms of the operations supported by the ledger object: (1) atomic consistency (linearizability), (2) sequential consistency, and (3) eventual consistency. We then provide implementations of distributed ledgers on asynchronous message passing crash-prone systems using an Atomic Broadcast service, and show that they provide eventual, sequential or atomic consistency semantics. We conclude with a variation of the ledger - the validated ledger - which requires that each record in the ledger satisfies a particular validation rule.
Alberto Sonnino, Mustafa Al-Bassam, Shehar Bano, Sarah Meiklejohn · 5 authors
Coconut is a novel selective disclosure credential scheme supporting distributed threshold issuance, public and private attributes, re-randomization, and multiple unlinkable selective attribute revelations. Coconut integrates with blockchains to ensure confidentiality, authenticity and availability even when a subset of credential issuing authorities are malicious or offline. We implement and evaluate a generic Coconut smart contract library for Chainspace and Ethereum; and present three applications related to anonymous payments, electronic petitions, and distribution of proxies for censorship resistance. Coconut uses short and computationally efficient credentials, and our evaluation shows that most Coconut cryptographic primitives take just a few milliseconds on average, with verification taking the longest time (10 milliseconds).
Abstract A functional credential allows a user to anonymously prove possession of a set of attributes that fulfills a certain policy. The policies are arbitrary polynomially computable predicates that are evaluated over arbitrary attributes. The key feature of this primitive is the delegation of verification to third parties, called designated verifiers. The delegation protects the privacy of the policy : A designated verifier can verify that a user satisfies a certain policy without learning anything about the policy itself. We illustrate the usefulness of this property in different applications, including outsourced databases with access control. We present a new framework to construct functional credentials that does not require (non-interactive) zero-knowledge proofs. This is important in settings where the statements are complex and thus the resulting zero-knowledge proofs are not efficient. Our construction is based on any predicate encryption scheme and the security relies on standard assumptions. A complexity analysis and an experimental evaluation confirm the practicality of our approach.
The trading volume of Bitcoin has increased immensely since its conception. Bitcoin is a cryptocurrency, it is not a legal currency but rather a private monetary system that manages by itself and does not depend on governments or central banks. It is an autonomous currency system that is not liable to any governing body. Some fear that the increase of Bitcoin usage, as it is quite different from traditional currencies and is free from control or regulations by monetary authorities. Although its popularity has grown worldwide, fluctuations of the prices are sometimes erratic. Hence, such large and sudden movements would dampen the sound development of Bitcoin. This paper examines how the volatile price of Bitcoin changes empirically. The empirical results show that there is a difference between short-term volatility and long-term volatility. Traders should see not only the short-term movements in volatile Bitcoin pricing but also long-term developments.
Purpose The purpose of this paper is to argue for the role of the blockchain, i.e., distributed ledger technology, in building innovative business models, including machine money, autonomous economic agents and decentralised organisations. Design/methodology/approach The paper is conceptual/argumentative. As such, it draws on research on (e-)commerce, theories of markets, disruptive innovation and extant studies and conceptual work at the intersection of cryptocurrencies, machine-to-machine commerce and the Internet of Things. Findings The authors highlight three application areas for blockchains, whereby they can function as applications, can help develop autonomous economic agents and can lead the development of decentralised autonomous organisations. With regards to the question of market disintermediation, the authors suggest that, rather than complete disintermediation, the most probable scenario is that of new types of intermediaries finding previously unthinkable roles to play in mediating blockchain-based economic transactions. With regards to the inhibitors that slow down the technology’s adoption and, therefore, the development of new business applications, the authors posit that these relate mainly to the inherent risk of the technology, infrastructure requirements, scepticism of early decision makers and the lack of required new skills and competencies. Originality/value The authors examine how new forms of digital money and technologies embedding trust in decentralised networks will alter markets and commerce, at a time when many regulatory issues remain unresolved; in doing so, the authors focus on how blockchain-enabled technologies can be used to enable and further develop decentralised trusted peer-to-peer transaction ledger systems and applications and lead to sustainable business models.
Blockchain is receiving increasing attention from academy and industry, since it is considered a breakthrough technology that could bring huge benefits to many different sectors. In 2017, Gartner positioned blockchain close to the peak of inflated expectations, acknowledging the enthusiasm for this technology that is now largely discussed by media. In this scenario, the risk to adopt it in the wake of enthusiasm, without objectively judging its actual added value is rather high. Insurance is one the sectors that, among others, started to carefully investigate the possibilities of blockchain. For this specific sector, however, the hype cycle shows that the technology is still in the innovation trigger phase, meaning that the spectrum of possible applications has not been fully explored yet. Insurers, as with many other companies not necessarily active only in the financial sector, are currently requested to make a hard decision, that is, whether to adopt blockchain or not, and they will only know if they were right in 3–5 years. The objective of this paper is to support actors involved in this decision process by illustrating what a blockchain is, analyzing its advantages and disadvantages, as well as discussing several use cases taken from the insurance sector, which could easily be extended to other domains.
Smart contracts---stateful executable objects hosted on blockchains like Ethereum---carry billions of dollars worth of coins and cannot be updated once deployed. We present a new systematic characterization of a class of trace vulnerabilities, which result from analyzing multiple invocations of a contract over its lifetime. We focus attention on three example properties of such trace vulnerabilities: finding contracts that either lock funds indefinitely, leak them carelessly to arbitrary users, or can be killed by anyone. We implemented MAIAN, the first tool for precisely specifying and reasoning about trace properties, which employs inter-procedural symbolic analysis and concrete validator for exhibiting real exploits. Our analysis of nearly one million contracts flags 34,200 (2,365 distinct) contracts vulnerable, in 10 seconds per contract. On a subset of3,759 contracts which we sampled for concrete validation and manual analysis, we reproduce real exploits at a true positive rate of 89%, yielding exploits for3,686 contracts. Our tool finds exploits for the infamous Parity bug that indirectly locked 200 million dollars worth in Ether, which previous analyses failed to capture.
Patrick G. Sylim, Fang Liu, Alvin Marcelo, Paul Fontelo
BACKGROUND Drug counterfeiting is a global problem with significant risks to consumers and the general public. In the Philippines, 30% of inspected drug stores in 2003 were found with substandard/spurious/falsely-labeled/falsified/counterfeit drugs. The economic burden on the population drug expenditures and on governments is high. The Philippine Food and Drug Administration (FDA) encourages the public to check the certificates of product registration and report any instances of counterfeiting. The National Police of Philippines responds to such reports through a special task force. However, no literature on its impact on the distribution of such drugs were found. Blockchain technology is a cryptographic ledger that is allegedly immutable through repeated sequential hashing and fault-tolerant through a consensus algorithm. This project will develop and test a pharmacosurveillance blockchain system that will support information sharing along the official drug distribution network. OBJECTIVE This study aims to develop a pharmacosurveillance blockchain system and test its functions in a simulated network. METHODS We are developing a Distributed Application (DApp) that will run on smart contracts, employing Swarm as the Distributed File System (DFS). Two instances will be developed: one for Ethereum and another for Hyperledger Fabric. The proof-of-work (PoW) consensus algorithm of Ethereum will be modified into a delegated proof-of-stake (DPoS) or practical Byzantine fault tolerance (PBFT) consensus algorithm as it is scalable and fits the drug supply chain environment. The system will adopt the GS1 pedigree standard and will satisfy the data points in the data standardization guidelines from the US FDA. Simulations will use the following 5 nodes: for FDA, manufacturer, wholesaler, retailer, and the consumer portal. RESULTS Development is underway. The design of the system will place FDA in a supervisory data verification role, with each pedigree type–specific data source serving a primary data verification role. The supply chain process will be initiated by the manufacturer, with recursive verification for every transaction. It will allow consumers to scan a code printed on the receipt of their purchases to review the drug distribution history. CONCLUSIONS Development and testing will be conducted in a simulated network, and thus, results may differ from actual practice. The project being proposed is disruptive; once tested, the team intends to engage the Philippine FDA to discuss implementation plans and formulate policies to facilitate adoption and sustainability. REGISTERED REPORT IDENTIFIER RR1-10.2196/10163
This article explores the mechanisms of the organization and operation of virtual payment systems. The appearance of such payment systems is associated with the development of Internet technologies in the field of mutual settlements for goods (works and services). The study aims at analyzing the classification, types of emission of cryptocurrencies, the mechanism of functioning of cryptocurrency systems; evaluating their impact on the monetary system and the involvement of individuals in the laundering of illegal incomes using cryptocurrencies; estimating prospects for the development of virtual payment systems in Russia and abroad, and defining mechanisms to counteract illegal activities. As a result, the current status of virtual cryptocurrency systems is estimated, their distinctive features and advantages are considered. The study also identifies drawbacks in the use of cryptocurrency with the involvement of individuals in the system of non-cash settlements. The results of the analysis of cryptocurrency systems can be useful for the improvement of the state monetary policy. Keywords: electronic money, bitcoin, cryptocurrency, blockchain, money laundering.
Maria Luisa Di Silvestre, Pierluigi Gallo, Mariano Giuseppe Ippolito, Eleonora Riva Sanseverino · 5 authors
The present paper considers some technical issues related to the “energy blockchain” paradigm applied to microgrids. In particular, what appears from the study is that the superposition of energy transactions in a microgrid creates a variation of the power losses in all the branches of the microgrid. Traditional power losses allocation in distribution systems takes into account only generators while, in this paper, a real-time attribution of power losses to each transaction involving one generator and one load node is done by defining some suitable indices. Besides, the presence of P-V nodes increases the level of reactive flows and provides a more complex technical perspective. For this reason, reactive power generation for voltage support at P-V nodes poses a further problem of reactive power flow exchange, which is worth of investigation in future works in order to define a possible way of remuneration. The experimental section of the paper considers a medium voltage microgrid and two different operational scenarios.
Chuka Oham, Salil S. Kanhere, Raja Jurdak, Sanjay Jha
The advent of autonomous vehicles is envisaged to disrupt the auto insurance\nliability model.Compared to the the current model where liability is largely\nattributed to the driver,autonomous vehicles necessitate the consideration of\nother entities in the automotive ecosystem including the auto\nmanufacturer,software provider,service technician and the vehicle owner.The\nproliferation of sensors and connecting technologies in autonomous vehicles\nenables an autonomous vehicle to gather sufficient data for liability\nattribution,yet increased connectivity exposes the vehicle to attacks from\ninteracting entities.These possibilities motivate potential liable entities to\nrepudiate their involvement in a collision event to evade liability. While the\ndata collected from vehicular sensors and vehicular communications is an\nintegral part of the evidence for arbitrating liability in the event of an\naccident,there is also a need to record all interactions between the\naforementioned entities to identify potential instances of negligence that may\nhave played a role in the accident.In this paper,we propose a BlockChain(BC)\nbased framework that integrates the concerned entities in the liability model\nand provides untampered evidence for liability attribution and adjudication.We\nfirst describe the liability attribution model, identify key requirements and\ndescribe the adversarial capabilities of entities. Also,we present a detailed\ndescription of data contributing to evidence.Our framework uses permissioned BC\nand partitions the BC to tailor data access to relevant BC\nparticipants.Finally,we conduct a security analysis to verify that the\nidentified requirements are met and resilience of our proposed framework to\nidentified attacks.\n
Today, more than 100 blockchain projects created to transform government systems are being conducted in more than 30 countries. What leads countries rapidly initiate blockchain projects? I argue that it is because blockchain is a technology directly related to social organization; Unlike other technologies, a consensus mechanism form the core of blockchain. Traditionally, consensus is not the domain of machines but rather humankind. However, blockchain operates through a consensus algorithm with human intervention; once that consensus is made, it cannot be modified or forged. Through utilization of Lawrence Lessig’s proposition that “Code is law,” I suggest that blockchain creates “absolute law” that cannot be violated. This characteristic of blockchain makes it possible to implement social technology that can replace existing social apparatuses including bureaucracy. In addition, there are three close similarities between blockchain and bureaucracy. First, both of them are defined by the rules and execute predetermined rules. Second, both of them work as information processing machines for society. Third, both of them work as trust machines for society. Therefore, I posit that it is possible and moreover unavoidable to replace bureaucracy with blockchain systems. In conclusion, I suggest five principles that should be adhered to when we replace bureaucracy with the blockchain system: 1) introducing Blockchain Statute law; 2) transparent disclosure of data and source code; 3) implementing autonomous executing administration; 4) building a governance system based on direct democracy and 5) making Distributed Autonomous Government(DAG).
This paper investigates a critical access control issue in the Internet of Things (IoT). In particular, we propose a smart contract-based framework, which consists of multiple access control contracts (ACCs), one judge contract (JC), and one register contract (RC), to achieve distributed and trustworthy access control for IoT systems. Each ACC provides one access control method for a subject-object pair, and implements both static access right validation based on predefined policies and dynamic access right validation by checking the behavior of the subject. The JC implements a misbehavior-judging method to facilitate the dynamic validation of the ACCs by receiving misbehavior reports from the ACCs, judging the misbehavior and returning the corresponding penalty. The RC registers the information of the access control and misbehavior-judging methods as well as their smart contracts, and also provides functions (e.g., register, update, and delete) to manage these methods. To demonstrate the application of the framework, we provide a case study in an IoT system with one desktop computer, one laptop and two Raspberry Pi single-board computers, where the ACCs, JC, and RC are implemented based on the Ethereum smart contract platform to achieve the access control.
Cryptocurrencies are becoming an attractive asset class and are the focus of recent quantitative research. The joint dynamics of the cryptocurrency market yields information on network risk. Utilizing the adaptive LASSO approach, we build a dynamic network of cryptocurrencies and model the latent communities with a dynamic stochastic blockmodel. We develop a dynamic covariate-assisted spectral clustering method to uniformly estimate the latent group membership of cryptocurrencies consistently. We show that return inter-predictability and crypto characteristics, including hashing algorithms and proof types, jointly determine the crypto market segmentation. Based on this classification result, it is natural to employ eigenvector centrality to identify a cryptocurrency’s idiosyncratic risk. An asset pricing analysis finds that a cross-sectional portfolio with a higher centrality earns a higher risk premium. Further tests confirm that centrality serves as a risk factor well and delivers valuable information content on cryptocurrency markets.
In this Perspective talk, I will explore how distributed ledger technology (DLT), often referred to as the Blockchain, can revolutionize the way we interact with data, can establish a network of trust amongst untrusting parties, and align incentives with sustainable practices. Recently, the UNFCCC has officially recognized the potential of DLT in fighting climate change. At the core of this technology is a distributed database that is continuously updated and verified by pre-defined algorithms run by the users. All data entering the distributed ledger (DL) is tamper-proof, chronological and distributed, and thus inherently durable, reliable, and secure. Additionally, the DL enables programmable (smart) contracts that self-execute and self-enforce based on captured data, preventing corruption and data manipulation. All machine-readable data can be stored and archived on a DL and used to validate claims. In a few years’ time, apps will make DLT feasible to use in most communities. Interesting use cases for the conservation of marine biodiversity include the transparent tracking of supply chains for fisheries, crowd-sourced reputation rankings for companies, automatic monetary incentives for measurable conservation actions in coastal communities, or secure and trustable peer-to-peer financing in underinvested areas, for example to develop resilient coastal social-ecological systems.
The Internet pervades many aspects of modern life offering up seemingly boundless opportunities to connect, inform and be informed. As the range and number of sources for information online explode, how people go about selecting and interpreting information has become a pertinent area for study, not least in the recent light of the prevalence of fake-news—as people are well known to act upon information they believe to be trustworthy. Where the decision to act incurs risk, an inability to accurately select and assess the credibility of information presents a challenge. <br/><br/>This extended abstract summarizes findings from a study of 57 Bitcoin users. Our analysis shows that this self-identifying technical and expert community was not significantly influenced by confirmation bias (a facet of fake-news). However, the same users also failed to demonstrate a true reliance upon the facts contained in news articles, often deferring trust to the source of the news which could still render them susceptible to fake-news, and, in turn, place their speculation of the crypto-currency at risk.