Alberto Sonnino, Shehar Bano, Mustafa Al-Bassam, George Danezis
We present a family of replay attacks against sharded distributed ledgers,\nthat target cross-shard consensus protocols, such as the recently proposed\nChainspace and Omniledger. They allow an attacker, with network access only, to\ndouble-spend or lock resources with minimal efforts. The attacker can act\nindependently without colluding with any nodes, and succeed even if all nodes\nare honest; most of the attacks can also exhibit themselves as faults under\nperiods of asynchrony. These attacks are effective against both shard-led and\nclient-led cross-shard consensus approaches. Finally, we present Byzcuit - a\nnew cross-shard consensus protocol that is immune to those attacks. We\nimplement a prototype of Byzcuit and evaluate it on a real cloud-based testbed,\nshowing that our defenses impact performance minimally, and overall performance\nsurpasses previous works.\n
Xinhua Zhu, Yigang Wei, Yani Lai, Yan Li · 6 authors
“Land finance” refers to the key fiscal strategy in which local governments in China generate revenue through land grant premiums and land tax revenues. A burgeoning body of literature has focused on the driving factors of China’s land finance from different aspects including fiscal decentralization, revenue decentralization, competition among local governments, land marketization, infrastructure development, and economic development. However, little research has provided a comprehensive perspective integrating social, economic and institutional aspects to investigate the driving forces of these unique and profound issues in China. This study aims to investigate the driving factors and working mechanism of land finance. A theoretical and empirical model was proposed using soft budget constraint theory and least squares structural equation modeling (PLS-SEM). The panel data of 35 Chinese major cities were assessed between 2006 and 2015. The empirical results contend the following: (1) the land transfer and fiscal systems provide the key impetus for land financing because the land transfer system forms a stable modality, and the fiscal system is an important incentive for land financing; (2) the effects of the economic development and political system are insignificant; and (3) the political and land systems significantly influence economic development. Our contributions focus on two aspects. Firstly, a comprehensive framework of factors germane to land finance is constructed. Secondly, a new research methodology for land use study is proposed. To the best of our knowledge, the current study is the first to employ the PLS-SEM method to delineate and verify the influence paths between multiple driving factors and land finance in different cities. Hence, research reliability can be improved.
IoT is a new communication paradigm that gains a very high importance in the past few years. This communication paradigm supports various heterogeneous applications in many fields and with the dramatic increase of the number of sensor devices, it becomes a demand. Designing IoT networks faces many challenges that include security, massive traffic, high availability, high reliability and energy constraints. Thus, new communication technologies and paradigms should be deployed for IoT networks to overcome these challenges and achieve high system performance. Distributed computing techniques (e.g. fog and MEC), software defined networking (SDN), network virtualization and blockchain are common recent paradigms that should be deployed for IoT networks, either combined or individually, to achieve the main requirements of the IoT networks at a high system performance. Fog computing is a form of edge computing that has been developed to provide the computing capabilities (e.g. storage and processing) at the edge of the access network. Employing Fog computing in IoT networks, as an intermediate layer between IoT devices and the remote cloud, becomes a demand to make use of the edge computing benefits. In this work, we provide a framework for the IoT system structure that employs an edge computing layer of Fog nodes controlled and managed by SDN network with the blockchain technology to achieve a high level of security for latency sensitive IoT applications. The proposed system employs SDN network with distributed controllers and distributed OpenFlow switches; these switches are enabled with limited computing and processing capabilities. Furthermore, a data offloading algorithm is developed to allocate different processing and computing tasks to the distributed OpenFlow switches with available resources. Moreover, a traffic model is proposed to model and analyze the traffic among different parts of the network. The proposed work achieves various benefits to the IoT network, such as the latency reduction, security improvement and high efficiency of resources utilization. The proposed algorithm is simulated and also the proposed system is experimentally tested over a developed testbed to validate the proposed structure. Experimental results show that the proposed system achieves higher efficiency in terms of latency, security and resource utilization.
Blockchain technology is one of the latest technologies on the horizon and has evolved over the last 7-10 years. There is tremendous potential for usage of Blockchain technology in today’s Real Estate industry. This paper aims to analyze the disruptive power of Blockchain digital technologies in the real estate industry. This paper will start with an introduction of the blockchain technology and high-level technical overview. It will then go on to discuss the various benefits the Real Estate industry can reap from this technology. It will also put forth various use cases or opportunities in the Real Estate sector for this technology. In the end, the paper will also discuss the present-day limitations and the questions marks over this technology in relation to its usage for the Real Estate industry.
Recent research on the economics of digitization investigates the dramatic changes in markets by digital technology. Digital technology has caused significant differences in in the cost of storage, computation, and transmission of data. As one of the latest sign of digitization in our life, the use of cryptocurrencies has been drawing attention of all market players. Blockchain technology is recently reallocating resources, restructuring of routines, changing market relationships and patterns of the flow of goods and services. This study investigates the coherence of Bitcoin with the movements of the main indicators of different markets. Aim of this research is to clarify whether this cryptocurrency follows the market conditions or not. Because the movements of the market values of Bitcoin are aimed to be investigated to show that they can be used separately as a tool of risk management. For this reason, wavelet analysis has been employed to define cross-correlation between time series of the daily USD value of Bitcoin and some market indicators. Some literature asserts that Bitcoin has recently started to follow market conditions. If Bitcoin process follows the market conditions more than before, that if This analysis will explain if there is a change in hedging possibility of Bitcoin recently.
It is argued here that because a cryptocurrency has no intrinsic value, problems relating to day-to-day valuation and pricing arise. It is shown how these lead to the reversal of the conventional relationship between supply and demand and the susceptibility of the cryptocurrency markets to irrationality and speculative bubbles arising from the herding instinct. Also, as the cryptocurrency markets are largely free of regulation and the desire for privacy by founders, owners and developers is so great, accountability and disclosure requirements are either minimal or non-existent, leading to the manipulation of cryptocurrency prices, volume and market capitalisation information. Another consequence of their freedom from regulation, particularly surprising given the importance placed on their security through the use of blockchain, is the magnitude of thefts of cryptocurrency (both in terms of frequency and size) levels of which would neither be expected nor tolerated in regulated financial markets.
In recent years, the status of cooperation and innovation has become increasingly important. Research on the behavior of production, education, and research organizations has attracted widespread attention. Blockchain technology is considered as another subversive technology following cloud computing, wireless sensor networks, and big data. It is highly concerned by governments, financial institutions, and technology companies. Blockchain technology is essentially a technical solution that collectively maintains a reliable database through a decentralized, high-trust way. Blockchain WEB technology has not only used in financial and other fields, but also has a great potential for application in the fields of production, education, and research. It has expected to play an important role in the establishment of a trust mechanism in the “Internet +” production, research, and innovation and promote education. Drawing on the experience in blockchain applications in the financial sector, the blockchain in the education sector mainly embodies six application modes: building individual science credit data, creating an intelligent education Taobao platform, developing a degree certificate system, and building a new ecology of open educational resources. Of course, due to the uniqueness and complexity of the trust field in the cooperation innovation of industry, universities, and research institutes, the application of blockchain technology is also faced with difficulties in the application, promotion, and operation of production and research, fuzzy ownership of educational big data, limited data storage space, and potential safety problems of blockchain technology. There are many challenges such as the privacy protection risks of teachers and students.
This paper analyzes the selfish-mine strategy in the Bitcoin blockchain introduced in 2013 by I. Eyal and E. G. Sirer. This strategy could be used by a colluding pool of miners to earn more than their fair share of the mining revenue and in consequence to force other honest miners to join them to decrease the variance of their revenues and make their monthly revenues more predictable. It is a very dangerous dynamic that could allow the rogue pool of miners to go toward a majority by accumulating powers of news adherents and control the entire network. Considering that the propagation delay of information between any two miners in the network, which is not negligible and follows a normal distribution with mean proportional to the physical distance between the two miners, and a constant variance independent of others' delays, we prove that no guarantee can be given about the success or failure of the selfish-mine attack because of the variability of information propagation in the network.
Ameer Tamoor Khan, Xinwei Cao, Shuai Li, Zoran Milošević
As a disruptive technology, blockchain, particularly its original form of bitcoin as a type of digital currency, has attracted great attentions. The innovative distributed decision making and security mechanism lay the technical foundation for its success, making us consider to penetrate the power of blockchain technology to distributed control and cooperative robotics, in which the distributed and secure mechanism is also highly demanded. Actually, security and distributed communication have long been unsolved problems in the field of distributed control and cooperative robotics. It has been reported on the network failure and intruder attacks of distributed control and multi-robotic systems. Blockchain technology provides promise to remedy this situation thoroughly. This work is intended to create a global picture of blockchain technology on its working principle and key elements in the language of control and robotics, to provide a shortcut for beginners to step into this research field.
Jorge Salmerón, Departamento de Economía, División de Ciencias Sociales y Humanidades, Universidad Autónoma Metropolitana -Unidad Azcapotzalco
En el siguiente trabajo se realiza un análisis sobre el comportamiento de los precios de seis criptomonedas: el Bitcoin, el Etherum, el Dash, el Ripple, el Litecoin y el Zcash, haciendo uso de vectores autorregresivos, funciones de impulso-respuesta, pruebas de causalidad de Granger y la prueba de cointegración de Johansen. El objetivo de la investigación es mostrar si existe relación de corto y/o largo plazo entre las variaciones en los precios de las criptomonedas, de tal forma que cuando los precios de alguna de éstas varían, las otras también fluctúan en relación a la variación de los precios de la criptomoneda en cuestión, y por tanto, intentar anticipar las fluctuaciones, en los precios de una criptomoneda, a partir de los movimientos de las demás.
Radhesh Krishnan Konoth, Rolf van Wegberg, Veelasha Moonsamy, Herbert Bos
In this study, we examine the behavior and profitability of modern malware that mines cryptocurrency. Unlike previous studies, we look at the cryptocurrency market as a whole, rather than just Bitcoin. We not only consider PCs, but also mobile phones, and IoT devices. In the past few years, criminals have attacked all these platforms for the purpose of cryptocurrency mining. The question is: how much money do they make? It is common knowledge that mining Bitcoin is now very difficult, so why do the criminals even target low-end devices for mining purposes? By analyzing the most important families of malicious cryptocurrency miners that were active between 2014 and 2017, we are able to report how they work, which currency they mine, and how profitable it is to do so. We will see that the evolution of the cryptocurrency market with many new cryptocurrencies that are still CPU minable and offer better privacy to criminals and have contributed to making mining malware attractive again -- with attackers generating a continuous stream of profit that in some cases may reach in the millions.
Hany F. Atlam, Robert John Walters, Gary Wills, Joshua Daniel
Abstract The Internet of Things (IoT) is becoming the future of the Internet with a large number of connected devices that are predicted to reach about 50 billion by 2020. With proliferation of IoT devices and need to increase information sharing in IoT applications, risk-based access control model has become the best candidate for both academic and commercial organizations to address access control issues. This model carries out a security risk analysis on the access request by using IoT contextual information to provide access decisions dynamically. This model solves challenges related to flexibility and scalability of the IoT system. Therefore, we propose an adaptive risk-based access control model for the IoT. This model uses real-time contextual information associated with the requesting user to calculate the security risk regarding each access request. It uses user attributes while making the access request, action severity, resource sensitivity and user risk history as inputs to analyze and calculate the risk value to determine the access decision. To detect abnormal and malicious actions, smart contracts are used to track and monitor user activities during the access session to detect and prevent potential security violations. In addition, as the risk estimation process is the essential stage to build a risk-based model, this paper provides a discussion of common risk estimation methods and then proposes the fuzzy inference system with expert judgment as to be the optimal approach to handle risk estimation process of the proposed risk-based model in the IoT system.
ABSTRACT The amendment of Government Regulation No. 24 of 2005 to Government Regulation No. 71 of 2010 based on accruals, made the government, especially the local government must apply and implement it no later than 5 years, namely in 2015. However, until now there are still many who do not fully understand the accounting-based accruals. There are various factors that influence government's preparedness and readiness in implementing accrual basis financial reporting. This study aims to analyze and examine the effects of environmental uncertainty, decentralization and assignment to accrual basis financial reporting. Population and sample in this research are Financial Administration Official of Regional Finance Organization (PPK-OPD) and Regional Finance Administration (PPKD) in Sidoarjo Regency. The study was conducted on 13 Local Government Organizations. The research method is quantitative and analytical technique using Multiple Linear Regression with SPSS data statistic application. The results of this study indicate that environmental uncertainty, decentralization and assignment have an effect on the accrual based financial reporting.Keywords : Environmental uncertainty, decentralization, task loading, Accrual based financial reportingCorrespondence to : momoepanda@gmail.com ABSTRAK Perubahan Peraturan Pemerintah Nomor 24 Tahun 2005 menjadi Peraturan Pemerintah Nomor 71 Tahun 2010 berbasis akrual, membuat pemerintahan khususnya pemerintah daerah wajib mengaplikasikan dan menerapkannya selambat-lambatnya 5 tahun, yaitu tahun 2015. Namun hingga saat ini masih banyak yang belum paham sepenuhnya dengan akuntansi berbasis akrual. Ada berbagai faktor yang mempengaruhi pemahaman dan kesiapan pemerintah dalam menerapakan pelaporan keuangan berbasis akrual. Penelitian ini bertujuan untuk mengetahui dan menguji pengaruh ketidakpastian lingkungan, desentralisasi dan pembeban tugas terhadap pelaporan keuangan berbasis akrual. Populasi dan sampel dalam penelitian ini adalah Pejabat Penatausahaan Keuangan Organisasi Pemerintahan Daerah (PPK-OPD) dan Pejabat Penatausahaan Keuangan Daerah (PPKD) di Kabupaten Sidoarjo. Penelitian dilakukan pada 13 Organisasi Pemerintahan Daerah. Metode penelitian yaitu kuantitatif dan teknik analisis menggunakan Regresi Linier Berganda dengan aplikasi statistik data SPSS. Hasil dari penelitian ini menunjukkan bahwa ketidakpastian lingkungan, desentralisasi dan pembebanan tugas berpengaruh terhadap pelaporan keuangan berbasis akrual.Kata kunci : Ketidakpastian lingkungan, desentralisasi, pemuatan tugas, pelaporan keuangan berbasis akrualKorespondensi : momoepanda@gmail.com
Ethereum clients execute transactions in a sequential order prescribed by the consensus protocol. This is a safe and conservative approach to blockchain transaction processing which forgoes running transactions in parallel even when doing so would be beneficial and safe, e.g., when there is no intersection in the sets of accounts that the transactions read or modify. In this work we study the degree of transaction parallelizability and present results from three different simulations using real Ethereum transaction data. Our simulations demonstrate that notable gains are achievable with parallelization, and suggest that the potential for parallelizability improves as transaction rates increase.
Cryptocurrency di indonesia sudah mulai berkembang serta mulai banyak digunakan oleh pelaku bisnis di indonesia. Hal inimenjadifenomenadalammemandangperlutidaknyaperlakuan akuntansi untuk transaksi cryptocurency. Penelitian ini mencoba menggali dan menguji crypto currency dan teknologi block chain dengan pendekatan dan tinjauan PSAK di Indonesia danfokus pada perlakuanakuntansi untuk cryptocurrency di Indonesia. Tujuan penelitian ini adalah melakukan kajian tentang akuntansi untuk crytocurrencyberdasarkan PSAK yang berlaku di indonesia. Penelitian ini menggunakan model literatur review untuk mengetahui akuntansi untuk cryptocurrency. Hasil penelitian menunjukkan belum adanya perlakuan akuntansi untuk transaksi cryptocurrency apakah diperlakukan sebagai kas, aset, atau persediaan.
 Cryptocurrency in Indonesia has begun to develop and is starting to be widely used by business people in Indonesia. This is a phenomenon in view of the need for accounting treatment for cryptocurency transactions. This research attempts to explore and test cryptocurrency and blockchain technology with the approach and review of PSAK in Indonesia and focus on the accounting treatment for cryptocurrency in Indonesia. The purpose of this study is to conduct a study of accounting for crytocurrency based on the applicable PSAK in Indonesia. This study uses a review literature model to find out accounting for cryptocurrency. The results of the study indicate that there is no accounting treatment for cryptocurrency transactions whether treated as cash, assets, or inventory.
Blockchain, which is a technology for distributedly managing ledger information over multiple nodes without a centralized system, has elicited increasing attention. Performing experiments on actual blockchains is difficult because a large number of nodes in wide areas are necessary. In this study, we developed a blockchain network simulator SimBlock for such experiments. Unlike the existing simulators, SimBlock can easily change behavior of nodes, so that it enables to investigate the influence of nodes' behavior on blockchains. We compared some simulation results with the measured values in actual blockchains to demonstrate the validity of this simulator. Furthermore, to show practical usage, we conducted two experiments which clarify the influence of neighbor node selection algorithms and relay networks on the block propagation time. The simulator could depict the effects of the two techniques on block propagation time. The simulator will be publicly available in a few months.
IoT devices are widely used in the smart home, automobile, and aerospace areas. Note, however, that recent information on thefts and hacking have given rise to many problems. The aim of this study is to overcome the security weaknesses of existing Internet of Things (IoT) devices using Blockchain technology, which is a recent issue. This technology is used in Machine-to-Machine (M2M) access payment—KYD (Know Your Device)—based on the reliability of existing IoT devices. Thus, this paper proposes a BoT (Blockchain of Things) ecosystem to overcome problems related to the hacking risk of IoT devices to be introduced, such as logistics management and history management. There are also many security vulnerabilities in the sensor multi-platform from the IoT point of view. In this paper, we propose a model that solves the security vulnerability in the sensor multi-platform by using blockchain technology on an empirical model. The color spectrum chain mentioned in this paper suggests a blockchain technique completed by using the multiple-agreement algorithm to enhance Thin-Plate Spline (TPS) performance and measure various security strengths. In conclusion, we propose a radix of the blockchain’s core algorithm to overcome the weaknesses of sensor devices such as automobile, airplane, and close-circuit television (CCTV) using blockchain technology. Because all IoT devices use wireless technology, they have a fundamental weakness over wired networks. Sensors are exposed to hacking and sensor multi-platforms are vulnerable to security by multiple channels. In addition, since IoT devices have a lot of security weaknesses we intend to show the authentication strength of security through the color spectrum chain and apply it to sensor and multi-platform using Blockchain in the future.
In this study, we investigate the relationship between Bitcoin mining technology variables and Bitcoin returns, using a GARCH-M model. Additionally, we examine the predictive power of the mining technology variables on future Bitcoin returns. We find that mining difficulty and block size are inversely related to Bitcoin returns. Additionally, our findings signifying that the higher the block size the lower the Bitcoin price and consequently the lower the expected return. Second, our findings show that mining difficulty and block size are robust predictors of future Bitcoin returns.
This research study shows the perspective of Islamic banking on Shariah compliant FinTech (financial technology) model. As startup firms providing and compete in the global market regarding financial services including e.g, online investment, Peer to peer equity crowdfunding, online payments (E-Wallets), philanthropic crowdfunding platforms, RegTech, Distributed ledgers technologies, crypto currency and many other threats of Distributed ledgers and digital currencies technological advancements. By keeping mentioned technological advancement, it is observed throughout the Islamic world by Shariah Experts and technology industry experts regarding Islamic FinTech ecosystem implementation. Primary data was collected through self administrative instrument with some previous research studies. Targeted population for this research contains Islamic and window Islamic banking staff, 150 respondents were approached with in the Karachi city. Testing shows positive results of independent to dependent variable of Shariah compliance relationship regarding FinTechmodel in Islamic banking according to Shariah-principles. Almost in the vicinity of Islamic banking and finance with FinTech implementation researches are under process in many universities or institutions throughout the world. Some researches shows positive results of FinTech aspects on Islamic banking services. Chosen independent variables have strong correlation with the dependent variable. Debated areas of FinTech and Islamic banking services have significant results produced under this research.
It is now a whole year since Lightning Network (LN) has been launched on the Bitcoi's mainnet. LN has been claimed as the solution for several of Bitcoin's weaknesses such as its difficulty to scale in number of transactions per second and its expensiveness for relative small amount exchanged. LN is based upon a network of micro-channels opened and closed by issuing transactions on the Blockchain and capable to interact among themselves thanks to the Multi-hop framework. In this work I analysed the evolution of LN from its topological point of view and tried to understand how it impacts over some of Bitcoin's historical core foundamentals such as the resilience against attacks and failures and the user's anonymity. Another question I have tried to answer is whether the evolution of LN's topology will make its synchronization easier.
Maxim Eugenyevich Demenkov, Ekaterina A. Demenkova, Svetlana Andreevna Shishmanova
The article highlights the approach to processing landed property data based on Blockchain technology and Ethereum platform, which allows the transparent, decentralized and highly reliable system for network users with restricted access to personal data. A review of the platforms for creating decentralized online services has been performed; their advantages and disadvantages considered. The inventory of the fields required for work with the landed property. There have been selected tools for working with Ethereum platform: browser Mist and the high-level language Solidity. To facilitate working with the inventory there were created a site with a map based on SharePoint platform and integrated using API Yandex.map. Peculiarity of the system under consideration is the need for trust between the participants who add data to the inventory. It has been proposed to use either a system based on a credible exchange of certificates, as they provide the high level of personal data security and have a service life, i.e. they are active only for one session, or a system of criteria for calculating the combined trust and assigning it to another person. Emphasis is made on the need to take into account the context of collaboration and shared services in trust management. The use of Blockchain technology for solving a practical task, namely, processing and storing spatial data on landed property, is an efficient way to store data, which will ensure the data relevance and reliability, as well as reduce their loss