This article presents a distributed ledger technology (blockchain) development analysis in throughout different socioeconomic spheres of the society. The highlight is the generalization and systematization of already known data, the main stages of blockchain technology development are classified, the blockchain technology implementation projections are presented in terms of new so-called «Digital economy» markets development. The paper describes a controversial situation when the blockchain is started to be used by banks to increase their efficiency and thereby indirectly contribute to the growth of popularity of crypto-currencies, which, in turn, creates an alternative to the existing financial infrastructure.
Open access
Economic and Technological Developments in Russia
Digitalization and Economic Development in Agriculture
Thomas Lundqvist, Andreas de Blanche, H. Robert H. Andersson
Thing-to-thing payments are a key enabler in the Internet of Things (IoT) era, to ubiquitously allow for devices to pay each other for services without any human interaction. Traditional credit card-based systems are not able to handle this new paradigm, however blockchain technology is a promising payment candidate in this context. The prominent example of blockchain technology is Bitcoin, with its decentralized structure and ease of account creation. This paper presents a proof-of-concept implementation of a smart cable that connects to a smart socket and without any human interaction pays for electricity. In this paper, we identify several obstacles for the widespread use of bitcoins in thing-to-thing payments. A critical problem is the high transaction fees in the Bitcoin network when doing micro transactions. To reduce this impact, we present a single-fee micro-payment protocol that aggregates multiple smaller payments incrementally into one larger transaction needing only one transaction fee. The proof-of concept shows that trustless, autonomous, and ubiquitous thing-to-thing micro-payments is no longer a future technology.
Michal PlaÄek, FrantiĆĄek Ochrana, Milan Jan PĆŻÄek, Milan KĆĂĄpek
Abstract This study tests whether decentralized leadership influences the efficiency of running selected cultural institutions, specifically museums in the Czech Republic. For the analysis, data from 2015 from 187 museums spread around the whole Czech Republic are used. The method for the evaluation of efficiency is data envelope analysis, and for identifying the influence of decentralized leadership, a regression analysis is used. Museums established by municipalities reach higher efficiency than museums established by regions and central government. The causes may be found in the ability to better estimate the local demand as well as in the rational behavior of municipalities that prefer a cost-minimization strategy. The benefits of decentralization cannot be seen only in the field of finance but also in reinforcing local traditions, trust and the effects of social capital that is generated by a strong regional cultural identity.
Blockchain technology is likely to be a key source of future financial market innovation. It allows for the creation of immutable records of transactions accessible by all participants in a network. A blockchain database is made up of a number of blocks ?chained? together through a reference in each block to the previous block. Each block records one or more transactions, which are essentially changes in the listed owner of assets. New blocks are added to the existing chain through a consensus mechanism in which members of the blockchain network confirm transactions as valid. The technology allows the creation of a network that is ?fully peer to peer, with no trusted third party, ? such as a government agency or financial institution.
We present the first measurement study of JoinMarket, a growing marketplace for more anonymous transfers in the Bitcoin ecosystem. Our study reveals that this market is funded with multiple thousand bitcoins and generated a turnover of almost 29.5 million USD over the course of 13 months. Assessing the resilience of the market against a well-funded attacker, we discover that in a typical scenario, a selective attack with a 90% success rate requires an investment of 14 000â54 000 USD (which is recoverable after the attack). We present economic arguments to explain the existence of this novel market for anonymity and underpin the hypothesis of heterogeneous time preference with empirical data.
We investigate how distributed denial-of-service (DDoS) attacks and other disruptions affect the Bitcoin ecosystem. In particular, we investigate the impact of shocks on trading activity at the leading Mt. Gox exchange between April 2011 and November 2013. We find that following DDoS attacks on Mt. Gox, the number of large trades on the exchange fell sharply. In particular, the distribution of the daily trading volume becomes less skewed (fewer big trades) and had smaller kurtosis on days following DDoS attacks. The results are robust to alternative specifications, as well as to restricting the data to activity prior to March 2013, i.e., the period before the first large appreciation in the price of and attention paid to Bitcoin.
Tareq Ahram, Arman Sargolzaei, Saman Sargolzaei, Jeff Daniels · 5 authors
Digital world has produced efficiencies, new innovative products, and close customer relationships globally by the effective use of mobile, IoT (Internet of Things), social media, analytics and cloud technology to generate models for better decisions. Blockchain is recently introduced and revolutionizing the digital world bringing a new perspective to security, resiliency and efficiency of systems. While initially popularized by Bitcoin, Blockchain is much more than a foundation for crypto currency. It offers a secure way to exchange any kind of good, service, or transaction. Industrial growth increasingly depends on trusted partnerships; but increasing regulation, cybercrime and fraud are inhibiting expansion. To address these challenges, Blockchain will enable more agile value chains, faster product innovations, closer customer relationships, and quicker integration with the IoT and cloud technology. Further Blockchain provides a lower cost of trade with a trusted contract monitored without intervention from third parties who may not add direct value. It facilitates smart contracts, engagements, and agreements with inherent, robust cyber security features. This paper is an effort to break the ground for presenting and demonstrating the use of Blockchain technology in multiple industrial applications. A healthcare industry application, Healthchain, is formalized and developed on the foundation of Blockchain using IBM Blockchain initiative. The concepts are transferable to a wide range of industries as finance, government and manufacturing where security, scalability and efficiency must meet.
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.
Blockchain is offering new opportunities to develop new types of digital services. While research on the topic is still emerging, it has mostly focused on the technical and legal issues instead of taking advantage of this novel concept and creating advanced digital services. In this paper, we are going to leverage the open source Blockchain technology to propose a design for a new electronic voting system that could be used in local or national elections. The Blockchain-based system will be secure, reliable, and anonymous, and will help increase the number of voters as well as the trust of people in their governments.
Open access
Internet Traffic Analysis and Secure E-voting
Advanced Steganography and Watermarking Techniques
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.
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.
This article demonstrates the possibility of constructing indicators of critical and crisis phenomena in the volatile market of cryptocurrency. For this purpose, the methods of the theory of complex systems such as recurrent analysis of dynamic systems and the calculation of permutation entropy are used. It is shown that it is possible to construct dynamic measures of complexity, both recurrent and entropy, which behave in a proper way during actual pre-crisis periods. This fact is used to build predictors of crisis phenomena on the example of the main five crises recorded in the time series of the key cryptocurrency bitcoin, the effectiveness of the proposed indicators-precursors of crises has been identified.
Dev P. Chakraborty, Robert M. Nishikawa, Colin G. Orton
One of the major roles of regulatory bodies is to enforce rules and thus maintain standards. They also often do research related to their missions, some of which might be used to establish the standards they are regulating and how they should be evaluated. This has led some to believe that, due to potential concerns of bias and conflicts of interest, regulatory bodies should not do evaluation methodology research related to their regulatory missions. This is the claim that is debated in this month's Point/Counterpoint. Arguing for the Proposition is Dev P. Chakraborty, Ph.D. Dr. Chakraborty earned his Ph.D. in solid state physics from the University of Rochester, New York in 1977 then, in 1979, began his career in medical physics working with Ivan Brezovich in the Department of Radiology, University of Alabama at Birmingham, AL, where he worked until 1988 before moving to the Department of Radiology, University of Pennsylvania, Philadelphia. He subsequently moved to the University of Pittsburgh, Pittsburgh, PA, in 1997, where he was Professor in the Department of Bioengineering before assuming his current position at ExpertCAD Analytics, LLC in 2016. He has published over 75 papers in peer-reviewed journals, many in the field of observer performance analysis. Arguing against the Proposition is Robert M. Nishikawa, Ph.D. Dr. Nishikawa received his B.Sc. in physics in 1981 and his M.Sc. and Ph.D. in Medical Biophysics in 1984 and 1990, respectively, all from the University of Toronto. While at the University of Chicago, he developed computer-aided diagnosis systems for classifying and detecting clustered calcifications in mammograms. He has seven patents on CAD-related technologies and has over 200 publications in breast imaging. He is currently a Professor and Director of the Clinical Translational Medical Physics Laboratory in the Department of Radiology at the University of Pittsburgh. He has won 24 awards including two for âbestâ paper, two innovation awards, and one teaching award. He is a fellow of the American Association of Physicists in Medicine, the Society of Breast Imaging, the College of American Institute for Medical and Biological Engineering, and a Distinguished Investigator, Academy of Radiology Research. His research interests are in computer-aided diagnosis, breast imaging, image quality assessment, and evaluation of medical technologies. The Food and Drug Administration (FDA) and the Center for Devices and Radiological Health (CDRH) both regulate imaging devices and claim leadership roles in how they are evaluated. To demonstrate that the CDRH leadership in imaging device evaluation research biases research in this area and results in suboptimal evaluation of new imaging devices, I will present a single extended example. CDRH scientists are leading proponents of FROC/ROC1, 2 methods for analyzing observer outcome studies. An alternative and often more efficacious approach is the JAFROC method3 pioneered in my laboratory. Does a computer-aided detection (CAD) manufacturer adopt evaluation methods developed by Chakraborty3 or does the manufacturer feel pressure to adopt the FDA's methods?1, 2 Chakraborty's methods/software (JAFROC) have been used in over 104 publications, but only 24 are from the US and none from the FDA. The chances that this low number is a fluke are astronomically small, especially given the much larger total numbers of published US studies relative to non-US studies. This is strong evidence the FDA has influenced US-researchers against using JAFROC. Most clinical trials, including the American College of Radiology Imaging Network (ACRIN) Digital Mammographic Imaging Screening Trial (DMIST),4 have used the lower power ROC paradigm for localization tasks, which is inappropriate and unethical:5 lower power means the study is either of dubious value or it is overly expensive. The location-specific method favored by the FDA1, 2 is based on the FROC curve: one can hardly do worse. FROC data consist of mark-rating pairs; marks are locations of suspicious regions and the rating is the associated confidence level. Based on a proximity criterion, a mark close to a lesion is scored as lesion localization (LL) and otherwise, it is non-lesion localization (NL). Lesion localization fraction (LLF) is defined as the number of LLs â„ threshold divided by the total number of lesions. The non-lesion localization fraction (NLF) is the number of NLs â„ threshold rating divided by the total number of images. The FROC curve (plot of LLF (ordinate) vs. NLF) rises with infinite slope from (0,0). The slope then decreases monotonically and the curve ends abruptly at an unpredictable point. The FROC is not contained within the unit square. This makes it impossible to define a meaningful area measure. The FROC is defined by marks: unmarked nondiseased cases, which represent perfect decisions, do not contribute to the area under the curve (AUC) under the FROC. In screening mammography, about 995 cases out of 1000 are nondiseased. The perfect radiologist, who marks all lesions and does not mark any nondiseased case, yields zero FROC AUC, receiving no credit for the 995 correct decisions. JAFROC is based on the AFROC (alternative-FROC) curve. The y-axis is similar to LLF, but the x-axis is the ROC false-positive fraction defined by the highest ratings on nondiseased cases, and the AFROC plot includes a connection from the uppermost operating point to (1,1). Unlike the FROC AUC, the AFROC AUC for the perfect observer is unity, not zero. JAFROC is ignored in FDA's Guidance Document,2 as are positive statements about JAFROC from the late Drs. Wagner and Metz,6 and there is not one reference to Chakraborty's work. The FDA's bias has doomed progress in breast cancer CAD (40,000 deaths/yr). Besides using incorrect FROC methodology, it has set a low (second reader) bar for CAD to be considered a âsuccessâ. The end result: massive clinical trials7 have shown that CAD is actually detrimental to the outcome and there has been a call to end CAD Medicare reimbursement.8 Regulation is necessary to balance the costs and benefits of implementing a product or activity. This raises two important issues. First, it is important to quantify costs and benefits accurately. Second, it is equally important for impartiality to acquire correct balances. The proposition directly addresses the second issue, but the first issue is necessary to discuss also. I will restrict my discussion to medical imaging devices for clarity. There are many well-established methods to determine the benefits of medical imaging devices.9 There are, however, situations where researchers need new evaluation methods, either for a new technology or to simplify tests for an existing type of technology. This requires research to develop and validate the new methodologies. The regulatory agencies need to understand the strengths and weaknesses of any tests presented to them as evidence for the effectiveness of a product. This would require regulatory agencies to either develop the expertise in-house or to rely on the scientific literature. That latter is insufficient for two reasons. First, regulatory science is not a well-funded branch of science. Therefore, unless the regulatory bodies perform the research, a disconnect may occur between developing the technologies and measuring their benefits and costs. This will either slow down approval of new technologies or lead to unbalanced regulations, or both. Second, reviewing the literature may be effective in understanding the basics of the evaluation methodology, but it is usually insufficient to understand the limitations of the method. Understanding the limitations is best done by applying the method, using simulations to a variety of situations, and evaluating the results. That is basically research and regulatory bodies benefit from conducting the studies themselves. While we can quantify benefits and costs, it is often difficult to decide on the proper balance of the two, particularly in an unbiased manner. Part of the difficulty arises from benefit and cost estimates not having the same units. A prime example of this, while not exactly in the regulatory domain, is the United States Preventative Services Task Force (USPSTF) recommendations on mammographic screening.10 We can evaluate the benefits of screening as lower mortality from breast cancer and costs as false-positive screens â recalling a woman for further imaging when, in fact, she does not have a breast cancer. It is not clear how to balance lives saved against more imaging and potentially an unnecessary biopsy. The USPSTF placed more weight on false-positive screens and chose not to recommend periodic screening for all women under the age of 50, compared to, for example, the American College of Radiology which supports annual screening of women 40 and older.11 Some proponents of screening argue that the USPSTF was biased in making their recommendations.12 There is no clear solution for this potential bias, but I do not believe that researching evaluation methodology is the right place to start. On the contrary, I believe there is less potential for bias when people are more knowledgeable â unless they are predisposed to a bias to begin with. Which is to say a bias can exist whether knowledge is obtained first hand or from reviewing the literature. I agree with my colleague that the FDA/CDRH needs to be current on the science. If regulatory science is not a well-funded branch of science, that makes it even more important to be current on the existing science, both from a revered in-house predecessor6 and from academia.3 I also agree that there is need for developing new evaluation methods, but then why is the new FDA/CRDH still wedded to the 1940s ROC paradigm; what is new about it? The âmechanisticâ approach13 that they are enamored with does not advance the state-of-the-art in general-paradigm multireader multicase (MRMC) analysis, rather it explains and generalizes the variance-component decomposition used in Dorfman/Berbaum/Metz analysis14 in a mathematically appealing way. But, and this is the serious limitation, it applies only to the Wilcoxon ROC statistic; it is not even applicable to fitted ROC curves, let alone FROC methodology. In my Opening Statement, I cited the âpowerâ imbalance when it comes to reviewing/vetting the work of the FDA/CDRH, and examples of questionable work. I could go on, especially how they validate methodologies. It is a brave and knowledgeable researcher who can properly review a paper15 listing as institution of origin: âNIBIB/CDRH Laboratory for the Assessment of Medical Imaging Systemsâ. Any applicant for an NIH grant in methodology development, and I see there is a recent funding opportunity announcement (PAR-17-125), would be well advised to cite this paper, never mind that it is about ROC analysis, while CAD provides FROC data, so at the very least the title of the paper is misleading. The cited work remains true to model observer philosophy, which assumes the lesion location is known, ignoring the fact that if location were known, there would be no need for a radiologist to find it. This entire debate would be of academic interest, but it was not for the implications for patient care: lives literally depend on the selection of proper imaging technology. Conducting ROC studies for search tasks is not only bad science but it is also unethical and a disservice to patients and taxpayers. My colleague Dev Chakraborty argues, I believe because it is not explicitly stated that the FDA, but principally the CDRH, is biased because it âforcesâ companies to use ROC analysis instead of JAFROC analysis, which Dev developed; and that this bias exists because members of the CDRH have done ROC research, but not FROC research. That is an interesting premise. Dev supports his assertion with statistics that are consistent with his view, but it does not constitute proof. Here is my prospective on Dev's claim of bias. First, I know many of the people at the CDRH. In my view, they are among the leaders in the field, both in terms of their scientific rigor and in their vision. The CDRH has a long history of significant and cutting edge research and establishing methodology for evaluating screen-film systems, digital systems, computer-aided diagnosis systems, ultrasound, and others. I have not seen signs of bias in my interactions with members of the CDRH. Certainly, the members have preferences, but they remain open-minded and fair. It is important to note that just as there are differences in approach between scientists in academia and industry, there are differences between scientists in the public service sector and academia (and industry). Scientists in the public are much more open to sharing data and ideas. Second, companies applying for FDA approval are, in my experience working with them, very conservative in their approach, and they basically follow any FDA precedent or previous approved applications. This is because the approval process can be time-consuming and expensive. Companies usually overpower their observer studies to include more readers and cases than what is required by an 80% power calculation. They do not want to risk having a null result because the observer study was underpowered. Furthermore, and more importantly, it is much easier and less risky just to copy a previously approved application. This will result in the same methods being perpetuated over time. So, when a company develops a new method, even if there are some benefits to it over existing techniques, they are less likely to use the new method in FDA submissions. This is the company's choice, not an FDA edict. So, while Dr. Chakraborty has presented evidence, it is all circumstantial and, until he produces a âsmoking gunâ, I believe that his assertion of bias at the CDRH is false. The authors have no relevant conflicts of interest to disclose.
E O Kiktenko, N O Pozhar, M N Anufriev, A S Trushechkin · 8 authors
Abstract Blockchain is a distributed database which is cryptographically protected against malicious modifications. While promising for a wide range of applications, current blockchain platforms rely on digital signatures, which are vulnerable to attacks by means of quantum computers. The same, albeit to a lesser extent, applies to cryptographic hash functions that are used in preparing new blocks, so parties with access to quantum computation would have unfair advantage in procuring mining rewards. Here we propose a possible solution to the quantum era blockchain challenge and report an experimental realization of a quantum-safe blockchain platform that utilizes quantum key distribution across an urban fiber network for information-theoretically secure authentication. These results address important questions about realizability and scalability of quantum-safe blockchains for commercial and governmental applications.
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.