Yanqi Zhao, Yannan Li, Qilin Mu, Bo Yang · 5 authors
The cyber physical system (CPS) has gained considerable success in large-scale distributed integration environment. In such systems, the sensor devices collect data which would be disseminated via reliable manner to all interested co-operant entities from the physical world. However, highly unreliable environment of CPS, for example, a number of limitations of existing network middle wares, makes secure and reliable data distribution services a challenge issue. In this paper, we propose a new architecture called secure pub-sub (SPS) without middle ware, i.e., blockchain-based fair payment with reputation. In SPS, publishers publish a topic on the blockchain and subscribers specify an interest message by making a deposit to subscribing the topic. Then, if the interest message matches the topic, the publisher transmits the encrypted content of the topic to the blockchain such that the subscribers can decrypt the ciphertext to obtain the content, and mark the publisher as its reputation. Finally, the publisher receives the payment from the subscriber. The new proposal provides confidentiality and reliability of data, anonymity of subscribers and payment fairness between the publishers and subscribers. Different from the traditional pub-sub services, no trusted third party is involved in our system due to employing blockchain technique. The security of the proposed SPS is analyzed as well. The implementation of the protocol on Ethereum of smart contract demonstrates the validity of SPS.
Bitcoin is the most popular cryptocurrency on the planet. It relies on strong cryptography and peer-to-peer network. Bitcoin is gaining more and more popularity in criminal society. That is why Bitcoin is often used as money laundering tool or payment method for illegal products and services. In this paper we explore various methods for Bitcoin users deanonimization, which is an important task in anti-money laundering process and cybercrime investigation.
The personal health information (PHI) is an activity among the health-care providers and the patients in terms of managing the data which is sensitive to the parties. The PHI data have been maintained by multiple health-care providers, thus resulting in separated data. Moreover, the PHI data are stored in the provider’s database, hence the patients have no authority to manage their own information. Therefore, in this article, we propose a conceptual model for managing the PHI data which is derived from several health-care providers by relying on the blockchain technology in the peer-to-peer overlay network. In addition, we elaborate the security analysis that might be occurring in the proposed model. By leveraging on our model, it allows the patients and the providers to collect effectively the PHI data onto a single view as well guarantee of data integrity. The blockchain offers an immutable of the data record without having to trust a third party. The experimental results show that the proposed approach is promising to be developed due to the high success rate in terms of data dissemination.
Jan 1, 2018·Proceedings of the ... Annual Hawaii International Conference on System Sciences/Proceedings of the Annual Hawaii International Conference on System Sciences
Gilbert Fridgen, Sven Radszuwill, Nils Urbach, Lena Utz
Bringing Blockchain technology and business process management together, we follow the Design Science Research approach and design, implement, and evaluate a Blockchain prototype for cross-organizational workflow management together with a German bank. For the use case of a documentary letter of credit we describe the status quo of the process, identify areas of improvement, implement a Blockchain solution, and compare both workflows. The prototype illustrates that the process, as of today paper-based and with high manual effort, can be significantly improved. Our research reveals that a tamper-proof process history for improved auditability, automation of manual process steps and the decentralized nature of the system can be major advantages of a Blockchain solution for cross-organizational workflow management. Further, our research provides insights how Blockchain technology can be used for business process management in general.
Internet of Things (IoT) and cloud computing are increasingly integrated, in the sense that data collected from IoT devices (generally with limited computational and storage resources) are being sent to the cloud for processing, etc., in order to inform decision making and facilitate other operational and business activities. However, the cloud may not be a fully trusted entity, like leaking user data or compromising user privacy. Thus, we propose a privacy‐preserving and user‐controlled data sharing architecture with fine‐grained access control, based on the blockchain model and attribute‐based cryptosystem. Also, the consensus algorithm in our system is the Byzantine fault tolerance mechanism, rather than Proof of Work.
Yunpeng Wang, Hui Zhao, Tao Li, Fan Zhang · 5 authors
The blockchain architecture with distributed and decentralized as the main features often face problems such as long transaction confirmation time, low system throughput, and waste of computing resources. These problems are exactly what the traditional centralized architecture can solve. At the same time, in order to improve the distributed consensus efficiency, consensus algorithms such as Proof of stake, delegated proof of stake, proof of space, proof of authority, and PBFT have emerged from Bitcoin's Pow consensus mechanism. These consensus algorithms have their own advantages and Disadvantages. Disadvantages, such as Pos, DPos can improve transaction efficiency, PBFT can improve the fairness of voting, but at the same time POS also bring benefits and voting rights to hold a lot of user tilt issues to a small number of tokens, PBFT brings about a low cost of malicious user attacks and other issues. In order to effectively take advantage of the high security, high reliability of the blockchain, and high efficiency of traditional centralized architectures, and fully utilizing existing consensus mechanisms, this paper presents an innovative hybrid blockchain approach, which mixed the blockchain architecture, Hybrid-chain, consists of the following three type nodes in the architecture: service center nodes responsible for efficient transaction confirmation, dynamic transaction verification nodes participating in transactions, and random verification nodes responsible for transaction fairness verification. On the consensus mechanism, the consensus algorithm selects the corresponding consensus mechanism according to the transaction characteristics. Experiments show that compared with the traditional blockchain architecture, hybrid chain has obvious performance advantages in transaction sending, transaction confirmation and block information storage, which can greatly reduce the transaction sending time by 96%, shorten the confirmation time by 95%, and reduce the number of 79. % Block information storage space, etc.
Over the last decade, blockchain technology has facilitated a method by which a network of equipotent and equally privileged peers can jointly maintain and edit databases in an entirely decentralized manner, without any kind of an intermediary exhibiting unilateral control. As a consequence it has enabled the creation of a new type of multi-sided platform architecture with distributed governance. As the different platform provision functions are opened to free market competition rather than monopolized by a single entity, the monopoly-like pricing structure typical of platforms is overhauled. Instead, blockchain-enabled distributed platforms appear to share value more evenly between the all the different market sides connected to the platform. Our analysis reveals that blockchain technology adds new considerations to how multi-sided platform architectures should be perceived and analyzed.
Online and offline storage of digital currency present conflicting risks for a Bitcoin exchange. While bitcoins stored on online devices are continually vulnerable to malware and other network-based attacks, offline reserves are endangered on access, as transferring bitcoins requires the exposure of otherwise encrypted and secured private keys. In particular, fluctuations in customer demand for deposited bitcoin require exchanges to periodically refill online storage systems with bitcoins held offline. This raises the natural question of what upper limit on online reserves minimizes losses due to theft over time. In this article, we investigate this optimization problem, developing a model that predicts the optimal ceiling on online reserves, given average rates of deposits, withdrawals, and theft. We evaluate our theory with an event-driven simulation of the setup, and find that our equation yields a numerical value for the threshold that differs by less than 2% from experimental results. We conclude by considering open questions regarding more complex storage architectures.
It is our great pleasure to welcome you to the WWW 2018 3rd International Workshop on Linked Data and Distributed Ledgers (LD-DL). We envision the workshop as a forum for researchers and practitioners from Distributed Ledgers and Linked Data to come together to discuss common challenges; propose solutions to shortcomings of existing architectures; and identify synergies for joint initiatives. The ultimate goal is the creation of a Web of Interoperable Ledgers. We received 6 submissions from all around the world. We evaluated them regarding relevance, quality, and novelty, selecting 3 short papers and 1 long paper (66% acceptance rate) --ScienceMiles - Digital currency for researchers--Can Blockchains and Linked Data Advance Taxation? --A distributed database with explicit semantics and chained RDF graphs--When trust saves energy: A Reference Framework for Proof of Trust (PoT) Blockchains. We hope that you will find the tutorial program interesting, providing you with a valuable opportunity to learn and share ideas with other researchers and practitioners from institutions around the world.
Permissioned distributed ledgers (permissioned blockchains) supporting smart contracts that automatically adjust accounts and coordinate records among multiple parties, present a valid platform opportunity for establishing a fully digital tax regime. We propose a permissioned blockchain-based system aimed at eliminating some of the losses that tax authorities globally are currently struggling with. These multi-billion flaws manifest themselves as the tax gap, or the inability to collect the full amount that is owed by a given entity to a particular authority. Illegitimate or inefficient tax operations could be prevented with a global suite of smart contracts deployed on top of a consortium distributed ledger with on-chain governance. We also introduce the vision for a VAT Invoice 2.0 modelled as a Linked Data document. A tax reference generated by a smart contract would allow anyone with the right permissions to immediately investigate the entire commercial chain for any taxable item on an ontology-based tax document.
Blockchain technologies have the potential to establish novel financial service infrastructures and reshape numerous fields. A blockchain is essentially a distributed ledger maintained by a set of peers (i.e., trading nodes) that do not fully trust each other. A key challenge that blockchain faces is to precisely classify the blockchain peers into categories with respect to their behavior patterns, which will not only enable deeper insights into the blockchain network but also facilitate more effective maintenance of the various peers (in private chains). In this paper, we introduce and formulate the problem of behavior pattern classification in blockchain networks and propose a novel deep-learning-based method, termedPeerClassifier, to address the problem. To the best of our knowledge, we are the first to formally define the problem of peer behavior classification in blockchain networks. Moreover, we conduct extensive experiments to evaluate our proposed approach. Experimental results demonstrate thatPeerClassifieris significantly more effective than the existing conventional methods.
C. Kouzinopoulos, Γεώργιος Σπαθούλας, Konstantinos M. Giannoutakis, Konstantinos Votis · 9 authors
Blockchain is a distributed ledger technology that became popular as the foundational block of the Bitcoin cryptocurrency. Over the past few years it has seen a rapid growth, both in terms of research and commercial usage. Due to its decentralized nature and its inherent use of cryptography, Blockchain provides an elegant solution to the Byzantine Generals Problem and is thus a good candidate for use in areas that require a decentralized consensus among untrusted peers, eliminating the need for a central authority. Internet of Things is a technology paradigm where a multitude of small devices, including sensors, actuators and RFID tags, are interconnected via a common communications medium to enable a whole new range of tasks and applications. However, existing IoT installations are often vulnerable and prone to security and privacy concerns. This paper studies the use of Blockchain to strengthen the security of IoT networks through a resilient, decentralized mechanism for the connected home that enhances the network self-defense by safeguarding critical security-related data. This mechanism is developed as part of the Safe-Guarding Home IoT Environments with Personalised Real-time Risk Control (GHOST) project.
Jan 1, 2018·Proceedings of the ... Annual Hawaii International Conference on System Sciences/Proceedings of the Annual Hawaii International Conference on System Sciences
Simon Albrecht, Stefan Reichert, J. Schmid, Jens Strüker · 6 authors
This case study analyzes the impact of theory-based factors on the implementation of different blockchain technologies in use cases from the energy sector. We construct an integrated research model based on the Diffusion of Innovations theory, institutional economics and the Technology-Organization-Environment framework. Using qualitative data from in-depth interviews, we link constructs to theory and assess their impact on each use case. Doing so we can depict the dynamic relations between different blockchain technologies and the energy sector. The study provides insights for decision makers in electric utilities, and government administrations.
Abstract This paper documents inconsistent terminologies and misleading analogies in current discussions of digital money and payments. It offers a more consistent framework for understanding the potential of technological innovation in providing the functions of money and payments: as media of exchange, stores of value, and units of account and the implications of cryptographic technologies underpinning cryptocurrencies for the future of money and payments. These could support efficiency gains in money and payments, but decentralization is not inherent to their application. Radical reform leading to improved economic outcomes is conceivable, but not through disruptive displacement of existing institutional arrangements.
Saide Zhu, Wei Li, Hong Li, Chunqiang Hu · 5 authors
The past three years have seen the rapid increase of Bitcoin difficulty, which has led to a substantial variance in solo mining. As a result, miners tend to join a large open pool to get a more stable reward. Nowadays, mining pools take up over 98% of Bitcoins total computation power. In a sense, this is a manifestation of Bitcoin that tends to be centralized. Thus, researchers have shown an increased interest in pool mining payoff and security. The purpose of this paper is to review and summarize recent research in Bitcoin pool mining system. We first introduce several common reward distribution schemes, and analyze their advantages and disadvantages with some improvement mechanisms; In the second section, to address pool security problems, we examined the practical utility of some existing and potential attack strategies. To study those malicious attack in details, several defense methods are collected. Finally, we make an outlook on Bitcoin future.
Bitcoin as a payment system indisputably offers an advantage over the government currencies in transaction time and costs. On the other hand the moneyness of Bitcoin itself is questioned. This paper analyzes Bitcoin from the Austrian perspective and compares the qualities of Bitcoin with qualities of good money in order to find out whether Bitcoin could serve as money. The examined properties are portability, storability, divisibility, recognizability, homogeneity and scarcity. Moreover it examines the consistency of Bitcoin emergence as a medium of exchange with Mises' regression theorem and identifies the non-monetary value of Bitcoin. The result of this theoretical analysis shows that Bitcoin's properties can facilitate the functions of money.
Bitcoin, a cryptocurrency invented in 2008 is both puzzling and inspiring. High volatility of its price is challenges financial analysts as well as scholars. We look at the incentive mechanisms that make Bitcoin work, and we discuss current and potential uses of Bitcoin and technologies inspired by it.