Blockchain, which is the backbone of Bitcoin, has recently received a lot of attention. Blockchain functions as an immutable ledger that enables decentralized transactions. Numerous fields, such as the Internet of Things (IoT), reputation systems, and financial services, are being covered by blockchain-based applications. However, blockchain technology still faces numerous difficulties, such as scalability and security issues, that need to be resolved. A comprehensive overview of blockchain technology is provided in this paper. First, we compare some common consensus algorithms utilized by various blockchains and provide an overview of the architecture of blockchains. In addition, a brief list of recent advancements and technical difficulties is provided. In addition, we outline potential blockchain trends for the future.
Zhijie Ren, Kelong Cong, Johan Pouwelse, Zekeriya Erkin
Recently, the blockchain technique was put in the spotlight as it introduced a systematic approach for multiple parties to reach consensus without needing trust. However, the application of this technique in practice is severely restricted due to its limitations in throughput. In this paper, we propose a novel consensus model, namely the implicit consensus, with a distinctive blockchain-based distributed ledger in which each node holds its individual blockchain. In our system, the consensus is not on the transactions, but on a special type of blocks called Check Points that are used to validate individual transactions. Our system exploits the ideas of self-interest and spontaneous sharding and achieves unbounded throughput with the transaction reliability that equivalent to traditional Byzantine fault tolerance schemes.
A comparative study across the most widely known blockchain technologies is conducted with a bottom-up approach. Blockchains are disentangled into building blocks. Each building block is then hierarchically classified in main and subcomponents. Then, alternative layouts for the subcomponents are identified and compared between them. Finally, a taxonomy tree summarises the study and provides a navigation tool across different blockchain architectural configurations.
There is little doubt that virtual currencies are here to stay in one form or another, and as means of payment, they invite if not require regulation and standardization to avoid abuse. Stakeholders of virtual currency regulation are companies involved in the blockchain economy, both new entrants and those already controlling part of the market; governments regulating both economic activity and consumer protection; and consumers. The interests of those parties naturally conflict, and given governmental regulatory powers, it is understandable that, faced with the significant risks and difficulties in coming up with a comprehensive regulatory concept, governments take a precautionary stance of wait and see, while in some cases leaning towards a prohibition of virtual currencies. But if regulators could start, more modestly, by finding ways to monitor virtual currency transactions and reliably identify their counterparties, the problem of money laundering and terrorist finance would be considerably easier to resolve than if conspirators were openly using bank wires and accounts in their own names. The problem, then, is not that it is impossible to control decentralized virtual currencies, but that state actors lack tools to decipher digital currency networks and gain access to the full measure of information contained therein. That, however, is more a question of cryptography and general computer science than of alien decentralized structures where traditional surveillance methods, such as wiretapping, simply will no longer work.
In the absence to date of any specific pre-emptive federal regulation of blockchain distributed ledger technology in fintech, smart contracts, or other uses, this paper discusses early state legislation including Arizona, California, Delaware, Hawaii, Illinois, Maine, New York, Nevada and Vermont. While the list comprises usual suspects for early adoption of disruptive technology regulation, especially of its real-time aspects that were recognized in In re Dole Food Co (Del. Ch. Feb. 15, 2017), the mechanics of blockchain are still evolving and restrictive regulations appear both premature and at risk of expedited obsolescence. Before expanding to general record-keeping transactions, blockchain was first used in bitcoin, a virtual currency. Then, blockchain evolved towards self-executing smart contracts using ethereum technology and may eventually reach an âInternet of Agreements.â While its promise for applications like virtual currencies and payments is obvious and vigorously explored by major financial institutions, blockchainâs real strength lies in authentication and keeping records up-to-date, especially for valuable, highly liquid assets like securities. Key developments for blockchainâs regulation and implementation in an evidentiary context occurred in Arizona (recognition of smart contracts), Vermont (blockchain as evidence), Chicago (real estate records), and, most importantly, Delaware (pending initiative authorizing registration of shares of Delaware companies in blockchain form). Since 64 percent of Fortune 500 companies and over 1 million entities are incorporated in Delaware, an enactment of Delawareâs initiative will change regulatory landscape for securities by setting precedent in the most important corporate jurisdiction of the U.S. Other states competing for corporate taxes and fees would be sure to follow.
Does real estate still have the value that it once had, or will the valuation of real estate change due to surprising products and services, innovative business models, different market strategies, innovative ways of organizing and managing in the (real estate) markets? Innovation revolves around good facilities in an attractive and stimulating environment. Take disruptive real estate for example. The driving forces behind these developments are new technology, viability, organizing differently, and managing, and these have a big impact on the valuation of real estate. Established names like Nokia, Kodak, Blockbuster, Oad, Free Record Shop, Hyves, and V&D collapse, and others, like Hema, Shell, hotel chains, and healthcare institutions are the least bothered by it. However, disruptive organizations like Amazon, Zalando, Uber, Tesla, and its competitor Faraday Future who wants to exceed Tesla in everything, clearly respond to viability in the environment, and this is determinative for competitive strength and thus impacts the current and future valuation of real estate. Blockchain-a distributed database that contains a growing list of data items and that is hardened against manipulation and counterfeiting-plays an important role in that. The notaries and brokers have already experienced this in the recent period, and it will continue to have an effect on real estate owners, financiers, users, builders, brokers, notaries, and the cadastre. The real estate world finds itself at a tipping point of a transition: a dramatic and irreversible shift in (real estate) systems in society.
May 28, 2017·CEUR Workshop Proceedings, Vol-2104: Proceedings of the 14th International Conference on ICT in Education, Research and Industrial Applications. Integration, Harmonization and Knowledge Transfer. Volume II: Workshops
The paper investigates the Bitcoin exchange rate response to the dai- ly Twitter data. Sentiment score is computed for the number of obtained tweets. The prediction accuracy for the Bitcoin exchange rate employing the sentiment score reveals the influence of the Twitter social network on the news diffusion and target exchange rate volatility. We used the historical data on the Bitcoin exchange rate and the daily sentiment score of the pertinent tweets to forecast the direction of change for the Bitcoin. The results show better performance of the developed forecasting method with both historical data on the exchange rate and the sentiment score than using only the exchange rate data as an input.
A. Seetharaman, A. Saravanan, Nitin Patwa, Jigar Mehta
In an era of technology advancement when the entire world is talking about the âInternet of Thingsâ whereby we are expected to have connectivity between anything and everything, Currency cannot be left behind. Paper currency is bound to be a thing of past, as virtual currencies will start taking over and Bitcoin is well poised to achieve this feat. Not only it will revolutionize the way payments are made, but also have potential to impact the future of world currencies like USD, which is already facing challenges from EURO or Chinese Yuan Renminbi (CNY). The rise of crypto-currencies will add a new dimension to this challenge for US Dollar (USD)The focus of this study is to understand multiple factors which are translating Bitcoin (BTC) that is gaining momentum in various fields of global finance and how disruptive it can be, including replacing main fiat currencies in the financial system impacting mainly USD. The key variables studied are Regulation or lack of it around Bitcoin, Bitcoin Technology, Bitcoin Economy and the usage of Bitcoin as a Currency. This research used the latest statistical tool ADANCO 1.1.1 by Henseler and Dijkstra (2015) to analyze the data collected by building a partial least squares structural equation model (PLS-SEM). The observations of this study will help understand the future of global finance from multiple standpoints, especially Regulation, Cryptocurrencies and the fiat currencies.
Hossein Shafagh, Lukas Burkhalter, Anwar Hithnawi, Simon Duquennoy
Today the cloud plays a central role in storing, processing, and distributing data. Despite contributing to the rapid development of IoT applications, the current IoT cloud-centric architecture has led into a myriad of isolated data silos that hinders the full potential of holistic data-driven analytics within the IoT. In this paper, we present a blockchain-based design for the IoT that brings a distributed access control and data management. We depart from the current trust model that delegates access control of our data to a centralized trusted authority and instead empower the users with data ownership. Our design is tailored for IoT data streams and enables secure data sharing. We enable a secure and resilient access control management, by utilizing the blockchain as an auditable and distributed access control layer to the storage layer. We facilitate the storage of time-series IoT data at the edge of the network via a locality-aware decentralized storage system that is managed with the blockchain technology. Our system is agnostic of the physical storage nodes and supports as well utilization of cloud storage resources as storage nodes.
This work show an avaliation about the performance of the application of Group Signature technique in Bitcoin system and a study about the anonymity and auditory. The Bitcoinâ goal is provide a virtual currency and an anonymous online transaction system. However, recent researches show that can be to break the anonymity of transactions through the chronological traceability technique in the Bitcoin transactions and analysis of network addresses. As a result of breaking anonymity of Bitcoin transactions, usersâ privacy and all Bitcoin ecosystem are affected negatively. For this reason, in this work, it was proposed to include Group Signatures techniques in the Bitcoin system to increasing of anonymity in Bitcoin transactions but with audity possibility in accept time, more or less 10 minutes. The Group Signature generate a lot of dinstinct groups to dinstinct Bitcoin transactions. After to include the Group Signature technique in a modified version of Bitcoin system, we evaluated this technique in Bitcoin system through experiment in simulations. Through the experiments and statistic analysis, it was found that the approach of including the Group Signature is feasible for implementation in Bitcoin system with small groups, 500 clients. For the all cases analyzed, it was verified that the use of Group Signature in Bitcoin transactions increase the anonymity. Therefore, it was verified that the performance of Bitcoin transactions with Group Signature technique show a delay in nearly 50% less than current Bitcoin system whitout this technique. Nevertheless, in small groups with Group Signature get a better anonymity level and audity, but in big groups with more than 500 clients this technique not is good because the transactions time is over.
The trend of digital currencies is catching fire these days, more and more people want to use digital currency. When we talk about digital currencies then how can we forget taking the name of Cryptocurrencies like Bitcoin. These currencies because of their P2P nature have won lot of hearts. You must have heard that "Every Rose has a thorn", similar type of thing is with Cryptocurrencies too. Because of the reason these currencies are P2P nature and there is no 3rd party who controls these cryptocurrencies, these are being used for illegal drugsarms dealing and for purchasing weapons online which are used in the terror attacks. We have found out a solution in order to put an end to it and the solution is Freezing of Assets. In this the owner will have the liberty to freeze any account whichever seem fishy and the freezed accounts will have their money intact, just the difference will be that they won't be able to transfer the money.
Abeer ElBahrawy, Laura Alessandretti, Anne Kandler, Romualdo PastorâSatorras · 5 authors
The cryptocurrency market surpassed the barrier of \$100 billion market capitalization in June 2017, after months of steady growth. Despite its increasing relevance in the financial world, however, a comprehensive analysis of the whole system is still lacking, as most studies have focused exclusively on the behaviour of one (Bitcoin) or few cryptocurrencies. Here, we consider the history of the entire market and analyse the behaviour of 1,469 cryptocurrencies introduced between April 2013 and June 2017. We reveal that, while new cryptocurrencies appear and disappear continuously and their market capitalization is increasing (super-)exponentially, several statistical properties of the market have been stable for years. These include the number of active cryptocurrencies, the market share distribution and the turnover of cryptocurrencies. Adopting an ecological perspective, we show that the so-called neutral model of evolution is able to reproduce a number of key empirical observations, despite its simplicity and the assumption of no selective advantage of one cryptocurrency over another. Our results shed light on the properties of the cryptocurrency market and establish a first formal link between ecological modelling and the study of this growing system. We anticipate they will spark further research in this direction.
Youngbin Kim, Jurim Lee, Nuri Park, Jaegul Choo · 6 authors
Bitcoin is an online currency that is used worldwide to make online payments. It has consequently become an investment vehicle in itself and is traded in a way similar to other open currencies. The ability to predict the price fluctuation of Bitcoin would therefore facilitate future investment and payment decisions. In order to predict the price fluctuation of Bitcoin, we analyse the comments posted in the Bitcoin online forum. Unlike most research on Bitcoin-related online forums, which is limited to simple sentiment analysis and does not pay sufficient attention to note-worthy user comments, our approach involved extracting keywords from Bitcoin-related user comments posted on the online forum with the aim of analytically predicting the price and extent of transaction fluctuation of the currency. The effectiveness of the proposed method is validated based on Bitcoin online forum data ranging over a period of 2.8 years from December 2013 to September 2016.
Pietro Danzi, Marko Angjelichinoski, Äedomir StefanoviÄ, Petar Popovski
Residential microgrids (MGs) may host a large number of Distributed Energy\nResources (DERs). The strategy that maximizes the revenue for each individual\nDER is the one in which the DER operates at capacity, injecting all available\npower into the grid. However, when the DER penetration is high and the\nconsumption low, this strategy may lead to power surplus that causes voltage\nincrease over recommended limits. In order to create incentives for the DER to\noperate below capacity, we propose a proportional-fairness control strategy in\nwhich (i) a subset of DERs decrease their own power output, sacrificing the\nindividual revenue, and (ii) the DERs in the subset are dynamically selected\nbased on the record of their control history. The trustworthy implementation of\nthe scheme is carried out through a custom-designed blockchain mechanism that\nmaintains a distributed database trusted by all DERs. In particular, the\nblockchain is used to stipulate and store a smart contract that enforces\nproportional fairness. The simulation results verify the potential of the\nproposed framework.\n
Bitcoin is a cryptocurrency which has received increasing interest over the last five years. Built upon a decentralized peer to peer system, it supports transparent, fast, cost effective, and irreversible transactions, without the need for trusting third party financial institutions. We know however little about people's motivation and experience with bitcoin currency. This paper reports on interviews with 20 bitcoin users in Malaysia about their experience and trust challenges. Findings show that bitcoins are used more as store of value for speculative investment or savings' protection. The paper advances the HCI theories on trust by identifying main bitcoin characteristics and their impact on trust, such as decentralization, unregulation, embedded expertise, and reputation, as well as transactions' transparency, low cost, and easiness to complete. We discuss insecure transactions, the risk of dishonest traders and its mitigating strategies. The paper concludes with design implications including support for the transparency of two-way transactions, tools for materializing trust, and tools for supporting reversible transactions.
Vanesa Daza, Roberto Di Pietro, Ivan Klimek, Matteo Signorini
The Internet of Things is gaining momentum thanks to the provided vision of seamlessly interconnected devices. However, a unified way to discover and to interact with the surrounding smart environment is missing. As an outcome, we have been assisting to the development of heterogeneous ecosystems, where each service provider adopts its own protocol- thus preventing IoT devices from interacting when belonging to different providers. And, the same is happening again for the blockchain technology which provides a robust and trusted way to accomplish tasks -unfortunately not providing interoperability thus creating the same heterogeneous ecosystems above highlighted. In this context, the fundamental research question we address is how do we find things or services in the Internet of Things. In this paper, we propose the first IoT discovery approach which provides an answer to the above question by exploiting hierarchical and universal multi-layered blockchains. Our approach does neither define new standards nor force service providers to change their own protocol. On the contrary, it leverages the existing and publicly available information obtained from each single blockchain to have a better knowledge of the surrounding environment. The proposed approach is detailed and discussed with the support of relevant use cases.
Michal Elzbieta Janton-Drozdowska, Alicja MikoĆajewicz-WoĆșniak
The year 2016 ended the period of migration from national payment services to the SEPA instruments and it has become apparent that some problems remained unresolved. Overcoming them requires finding suitable technological solutions. The potential of distributed ledger technology (DLT) is currently explored by financial sector and its implementation may affect the SEPA schemes in a variety of dimensions. The aim of the article is to determine the potential impact of the DLT transfer to banking sector on the future SEPA's functioning. The paper presents SEPA's assumptions and the project's current status as well as DLT's concept. It describes the technology transfer implications for banking industry and compares currently operating SEPA schemes with those based on DLT. It also indicates opportunities and threats being the consequence of the new technology implementation and their significance for SEPA.In the article the qualitative analysis is supplemented by the quantitative one. While characterizing the functioning of the main pillars of the SEPA Schemes the elements of descriptive statistics are used. The final conclusions are based on the comparative analysis of SEPA schemes and developed DLT applications. The existing problems might be solved by supplementing currently operating SEPA payment schemes with the applications based on DLT. The developed systems shall provide required real-time processing and a global reach as well as extend the SEPA schemes' functionalities with the ability to transfer other currencies. The technology implementation shall result not only in new financial products but first of all - in creating new business models. Consequently, we shall expect the modification of currently operating SEPA schemes, based rather on their supplement than total replacement in a short time horizon.
Bugs severely hurt blockchain system dependability. A thorough understanding of blockchain bug characteristics is required to design effective tools for preventing, detecting and mitigating bugs. We perform an empirical study on bug characteristics in eight representative open source blockchain systems. First, we manually examine 1,108 bug reports to understand the nature of the reported bugs. Second, we leverage card sorting to label the bug reports, and obtain ten bug categories in blockchain systems. We further investigate the frequency distribution of bug categories across projects and programming languages. Finally, we study the relationship between bug categories and bug fixing time. The findings include: (1) semantic bugs are the dominant runtime bug category, (2) frequency distributions of bug types show similar trends across different projects and programming languages, (3) security bugs take the longest median time to be fixed, (4) 35.71% performance bugs are fixed in more than one year, performance bugs take the longest average time to be fixed.
Blockchain is the technology at the core of what could become the "Fintech" transformation of capital markets. It can potentially facilitate cheaper, more efficient and secure operations. The mechanism behind it is introduced in this paper, as are its uses and suggested areas for future academic research. The paper critically reviews the promise that blockchain and distributed ledgers will speed up financial settlements and transactions. In it we recommend financial institutions evaluate the adoption of blockchain and/or adapt their existing legacy systems to allow for digital clearing over the internet.
Just like its recent predecessors, blockchain â also known as the distributed ledger technology â is considered to have the potential to cause major economic, political and social transformations in the Global South. The visible effects of this technology are already being noted there. We present early evidence linking the use of blockchain in overcoming some economic, social and political challenges facing the Global South. The article highlights the key applications and uses of blockchain in developing countries. It demonstrates how blockchain can help promote transparency, build trust and reputation, and enhance efficiency in transactions. The article looks at opportunities and key triggers for blockchain diffusion in these countries. It also delves into challenges and obstacles that developing economies are likely to encounter in the use of blockchain.