In the era of digitalization, crypto-currency has become the talk of the town and Bitcoin is one of it. Bitcoin System is not controlled by any central authority or governed by any management division. Bitcoin is the first digital decentralized currency and its economic growth has encompassed to billions of dollars within a few years. In this paper we present detailed Introduction to the digital currency including the crypto-currency, then we present Bitcoin system in depth with the process of transactions, mining, miners' pooling. As we know that the popularity of Bitcoin is increasing day by day so are the attacks. We present an analysis of major attacks in the Bitcoin system such as eclipse attack, Sybil attack, >51% attack, selfish mining. More importantly, we present how these attacks play an important role for the attackers in order to receive unfair incentives or fraud the honest users. The current researchers are focusing on creating new protocols as defensive measures for the attacks; we also analyze the security of these protocols.
Some of the appealing characteristics of distributed ledger technology (DLT), which blockchain is a type of, include guaranteed integrity, disintermediation and distributed resilience. These characteristics give rise to the possible consequences of immutability, unclear ownership, universal accessibility and transborder storage. These consequences have the potential to contravene data protection principles of Purpose Specification, Use Limitation, Data Quality, Individual Participation and Transborder Data Flow. This paper endeavours to clarify the various types of DLTs, how they work, why they exhibit the depicted characteristics and the consequences. Using the universal privacy principles developed by the Organisation of Economic Cooperation and Development (OECD), this paper then describes how each of the consequence causes concerns for privacy protection and how attempts are being made to address them in the design and implementation of various applications of blockchain and DLT, and indicates where further research and best-practice developments lie.
The recent explosion of interest in blockchains led to a plethora of proposals for their application, including attempts to decentralize some centralized network functions. At the same time, real "distributed wireless networks" are emerging. Community networks, for instance, are large mesh networks made of hundreds of nodes built by communities primarily to solve digital divide, and they are thriving. The challenges these networks face are not only technological: they deal with creating incentives to participate, with the business model they may adopt, and with their internal governance. Very few models have been proposed to apply blockchains to bottom-up distributed networks: we instead expose how they can solve many problems which so far hindered the diffusion of such networks. Maybe we can push this further: a network is, in essence, a system in which all nodes find a rough consensus on the best paths to connect a node with another. Can we use this consensus method to run a distributed ledger and a cryptocurrency within the network itself, rather than simply applying to networks the effects of a blockchain defined in a separate system? This paper introduces this concept, named "Proof of Networking", and discusses its potential avails.
As proof-of-work blockchains are inherently energy greedy and offer probabilistic guarantees, blockchains based on Byzantine consensus appear as a promising technology to track billions of connected devices. In this paper, we evaluate the performance of prominent blockchains that solve the classic Byzantine consensus problem. Our results show that while offering reasonable throughput their performance usually do not scale to tens of devices and drops dramatically as the number of devices increases. This study motivates the need for solutions that solves the Blockchain consensus problem, a scalable variant of the classic Byzantine consensus problem but dedicated to blockchains.
In this fast pacing world of modernisation, people are moving ahead at the expense of affecting the society cataclysmically and making the people more standoffish and aloof. Some people are becoming too competitive to earn money while others have no clue how about getting even a penny. But at the same time, there exist people who wish to contribute to the society out of altruism. But the existing centralised systems and brokers for charities are so corrupt that people lose belief in these trustless systems and hence the charities become futile. What if we can use the rapacious ideology of money minded people coupled with the modern technology to make the charity system more effective and trustful. Using an approach of decentralisation, cryptocurrency and finance for donations, the system of charity can be improved to a great extent with the added advantage of the involvement of even these people in a conducive way. We propose a system, backed by cryptocurrency transactions, to make the system of charity more transparent and trustworthy where the charity (in form of work) by individuals or organizations is done first and then that work can be sold later as a stock (here we call it a certificate). This will work in a manner similar to the exchange market using crypto-currency. So, people can raise money out of it, just like stocks but finally the money would go to the charities, as the certificates can only be generated by the charity doers. The complete system will be decentralised using Blockchain Technology, Smart Contractsl[2]and Cryptocurrency. This system would facilitate any individual to contribute independently to the society using his time and abilities apart from just money, and ultimately this will lead to an increase in hands towards the amelioration of the society.
Using soft budget theory to explore the formation mechanism and the deep institutional incentive of the local financing platform debt expansion from the perspective of fiscal / financial decentralization, construct theoretical framework which explain the expansion of local debt financing platform and conduct an empirical test, the results showed that the higher the degree of fiscal decentralization, fiscal autonomy as a soft constraint body of local government the stronger, local financing platform debt scale is greater; the higher the degree of financial decentralization, local government and financial institutions have the higher autonomy with respect to the central, local financing platform debt scale is bigger; financial synergy degree is stronger, local government financial mutual supervision prompted the local government debt more transparency, local debt financing platform size is smaller.
Tan provides a novel approach to understanding the politics of the Roman Republic—follow the money. In the process, he breaks through a long-standing loggerhead in the debate about the political character of the Republic: Was it fundamentally aristocratic, with a narrow set of families dominating high office in the city, or basically democratic, given that citizen assemblies elected magistrates and passed legislation?Tan argues that the Roman people had the most leverage over state policy when they paid taxes, particularly a property tax called tributum. After the conquest of Macedonia in 167 b.c., tributum was permanently suspended, and the Roman state financed itself largely from the proceeds of empire. The Roman populace being less interested in how other people’s money was spent, elites enjoyed freer reign. The aristocracy then chose to maintain a fiscally weak and decentralized state. Because few Roman senators would ever hold the highest offices (consul or censor), they therefore had a collective interest in keeping the state underfunded to limit the resources available to the fortunate few who did. This dynamic explains the decline of public-works projects after the 140s b.c. Most importantly, maintaining a poor state allowed the aristocracy to funnel the wealth of the Mediterranean into their own coffers.Despite rapid overseas expansion, Roman public revenues increased only modestly during the second and first centuries b.c., while private fortunes skyrocketed. Rome did not follow the trajectory of modern states, where, in Tilly’s axiom, “war made the state and the state made war.”1 Instead, the relatively underdeveloped Roman state handily won wars, but the elite declined to engage in further state building or resource maximization of the sort theorized by Levi.2 Roman aristocrats had a theory of predatory rule, but mainly for the purposes of personal enrichment. According to Tan, one reason for the Roman introduction of provincial tax farming was the opportunity that it afforded governors and their staffs to enrich themselves, given that this corruption did not impact the fixed amount guaranteed to the public treasury through the tax farmers’ contract.The second part of the book tacks back to the First and Second Punic Wars (264-241 and 218-201 b.c., respectively), when the state was still funded in large part by tributum, and citizen assemblies routinely interjected themselves into the conduct of wars. Tan is correct to correlate such ground-level activism with taxpaying. He largely ignores the parallel role of military conscription as a motivator for active political participation (although serving in the legions was a way to avoid tributum). Roman citizens provided the blood, as well as the treasure, that fueled the war effort; such sacrifices certainly persisted after 167 b.c. Tan points to several moments, however, when money was undoubtedly the main point of contention between the aristocracy and the commons—as when citizens voted to reject peace with Carthage in 241 b.c. until the indemnity paid to Rome was substantially increased.Tan closes with a discussion of the murder of the Gracchi brothers (Tiberius in 133 b.c. and Gaius in 121 b.c.) at the hands of their senatorial colleagues. Their “crimes” were steps to regularize and intensify the fiscal power of the state at the expense of aristocratic initiative—Tiberius’ law appropriating the revenues of Asia and Gaius’ establishment of a permanent grain dole. Tan would have done well to discuss the late republic in greater detail; his methodology would do much to illuminate the running disputes about the corruption courts, the continued presence of radical tribunes, and the rise of military dynasts commissioned by popular laws. A sequel would be welcome.This revelatory book creatively employs the methods of fiscal sociology to provide new perspectives on Rome’s turbulent politics. Tan’s accessible vision of a republic ruined by a predatory elite, an inattentive populace, and destabilizing concentrations of wealth is a cautionary tale that would benefit an audience of concerned scholars outside the narrow circle of ancient historians.
Blockchain technology and the application of smart contracts allow for automation of verifiable digital processes between any number of parties. The Internet of Things (IoT) has seen great potential in the past decade to revolutionise our day-to-day lives with the aim of automating physical processes by incorporating Internet-connected devices into commodities. By integrating the IoT with blockchain systems and smart contracts it is possible to provide verifiable automation of physical processes involving different parties. The challenge lies in that due to resource constraints, many of the computational devices used within the IoT are not capable of directly interacting with blockchain implementations. In this paper, we describe and give a reference design and implementation of a split-virtual machine, AlkylVM, which allows for resource constrained IoT devices to interact with blockchain systems.
Public sector and governments have been actively exploring new technologies to enable the smart services transformation and to achieve strategic objectives such as citizens satisfaction and happiness, services efficiency and cost optimization. The Blockchain technology is a good example of an emerging technology that is attracting government attention. Many government entities such as United Kingdom, Estonia, Honduras, Denmark, Australia, Singapore and others have taken steps to unleash the potential of Blockchain technology. Dubai Government is aiming to become paperless by adopting the Blockchain technology for all transactions by 2021. The Blockchain is a disruptive technology that is playing a vital role in many sectors. It's a revolutionary technology transforming the way we think about trust as it enables transacting data in a decentralized structure without the need to have trusted central authorities. Blockchain technology promises to overcome security challenges in IoT enabled services such as enabling secure data sharing and data integrity. However, it also introduces new security challenges that should be investigated and tackled. In this paper, we review the literature to identify the potential use cases and application of Blockchain to enable government services. We also synthesized literature related to the security of Blockchain implementations to identify the security benefits, challenges and the proposed solutions. The analysis shows that is huge potential for Blockchain technology to be used in to enable smart government services. This paper also highlights future research in the areas of concerns that required further investigation.
Internet of Things (IoT) is now in its initial stage but very soon, it is going to influence almost every day-to-day items we use. The more it will be included in our lifestyle, more will be the threat of it being misused. There is an urgent need to make IoT devices secure from getting cracked. Very soon IoT is going to expand the area for the cyber-attacks on homes and businesses by transforming objects that were used to be offline into online systems. Existing security technologies are just not enough to deal with this problem. Blockchain has emerged as the possible solution for creating more secure IoT systems in the time to come. In this paper, first an overview of the blockchain technology and its implementation has been explained; then we have discussed the infrastructure of IoT which is based on Blockchain network and at last a model has been provided for the security of internet of things using blockchain.
Enterprises have paid attention to blockchain (BC), recently permissioned BC characterized with smart-contract, where business transactions among inter-authorized companies (forming consortium) can automatically be executed based on distributed consensus protocol over user-defined business logics pre-built with program codes. A single BC system will be built across multiple management domains having different operational policies, e.g., datacenter of each organization; this will trigger a problem that its system operations (e.g., backup) will become time-consuming and costly due to the difficulty in unifying and/or adjusting operational policy, schedule, etc. Toward solving the problem, we propose an operations execution method for BC systems; a primary idea is to define operations as smart-contract so that unified and synchronized cross-organizational operations can be executed effectively by using BC-native features. We de-sign the proposed method as hybrid architecture including in-BC consensus establishment and out-BC event-based instruction execution, in order to be adaptable to the recent heterogeneous BC architecture. Performance evaluation using a prototype with Hyperledger Fabric v1.0 shows that the proposed method can start executing operations within 5 seconds. Furthermore, cost evaluation using model-based estimation shows that the total yearly cost of monthly operations on a 5-organizational BC system could be reduced by 61 percent compared to a conventional manual method.
Ence Zhou, Hua Song, Bingfeng Pi, Jun Sun · 7 authors
Currently, Bitcoin and Ethereum are the two most popular cryptocurrency systems, especially Ethereum. It permits complex financial transactions or rules through scripts, which is called smart contracts. Since Ethereum smart contracts hold millions of dollars, their execution correctness is crucial against attacks which aim at stealing the assets. In this paper, we proposed a security assurance method for smart contract source code to find potential security risks. It contains two main functions, the first is syntax topological analysis of smart contract invocation relationship, to help developers to understand their code structure clearly; the second is logic risk (which may lead to vulnerabilities) detection and location, and label results on topology diagram. For developers' convenience, we have built a static analysis tool called SASC to generate topology diagram of invocation relationship and to find potential logic risks. We have made an evaluation on 2,952 smart contracts, experiment results proved that our method is intuitive and effective.
Blockchain technology has attracted increasing attention in recent years. One reason of this new trend is the introduction of on-chain smart contracts enabling the implementation of decentralized applications in trust-less environments. Along with its adoption, attacks exploiting smart contract vulnerabilities are inevitably growing. To counter these attacks and avoid breaches, several approaches have been explored such as documenting vulnerabilities or model checking using formal verification. However, these approaches fail to capture the Blockchain and users behavior properties. In this paper, we propose a novel formal modeling approach to verify a smart contract behavior in its execution environment. We apply this formalism on a concrete smart contract example and analyze its breaches with a statical model checking approach.
Andreas Unterweger, Fabian Knirsch, Christoph Leixnering, Dominik Engel
Real-world smart contracts which preserve the privacy of both, their users and their data, have barely been proposed theoretically, let alone been implemented practically. In this paper, we are the first to implement a privacy-preserving protocol from the energy domain as a smart contract in Ethereum. We elaborate on and present our implementation as well as our practical findings, including more or less subtle traps and pitfalls. Despite major optimizations to our implementation, we find that while it is currently possible, it is not feasible to implement a privacy-preserving protocol of modest complexity in the Ethereum blockchain due to the high cost of operation and the lack of privacy by design.
One of the most popular platform based on blockchain technology is Ethereum. Internal activity on this public blockchain is analyzed both from a quantitative and qualitative point of view. In a first part, it is shown that the creation of the Ethereum Alliance consortium has been a game changer in the use of the technology. In a second part, the network robustness against attacks is investigated from a graph point of view, as well as the distribution of internal activity among users. Addresses of great influence were identified, and allowed to formulate conjectures on the current usage of this technology.
Beltrán Borja Fiz Pontiveros, Robert Norvill, Radu State
In this work we propose a compression method for smart contracts deployed in the Ethereum blockchain. By taking advantage of the repetition of sections of bytecode among multiple smart contracts previously deployed in the Ethereum blockchain we propose a new pseudo opcode that acts as a pointer that will allow smart contracts to reuse previously deployed code. We show that our proposed algorithm achieves space savings of up to 75% in a dataset of deployed Ethereum smart contracts bytecode, on par with other state of the art compression algorithms while remaining compatible with other methods currently in use for space reduction.
M Vaidehi, Alivia Pandit, Bhaskar Jindal, Minu Kumari · 5 authors
After the boom and bust in cryptocurrencies’ prices in recent years, Bitcoin has been totally regarded as an investment asset. As it is highly volatile in nature, there has been a need for good predictions for carrying base investment decisions. Although current study has used machine learning for more accurate Bitcoin price prediction, some of them did focused on the feasibility of applying different modeling techniques to the samples that has different data structures and dimension features. To predict Bitcoin price on different frequencies after using machine learning techniques, firstly we have to classify the Bitcoin price with daily price and high-frequency price. Here, we attempt to predict Bitcoin price as accurately as possible by taking into consideration various protocols that affect the Bitcoin value. Using the provided data we would predict the sign of daily price change with highest possible accuracy. We have used Random Forest Classifier and compared with benchmark results as daily price prediction, we achieve a better performance, with the highest accuracies of the statistical methods and machine learning algorithms of 99%. my investigation in Bitcoin price prediction can be considered as a pilot study for the importance of the sample dimension in the machine learning techniques. Keywords Bitcoin, Crypto Currency, Machine Learning, Blockchain, Long Short Term Memory(LSTM), Recurrent Neural Network(RNN), Prediction
We examine the significance of twenty-one potential drivers of bitcoin returns for the period 2010–2017 (2533 daily observations). Within a LASSO framework, we examine the effects of factors such as stock market returns, exchange rates, gold and oil returns, FED’s and ECB’s rates and internet trends on bitcoin returns for alternate time periods. Search intensity and gold returns emerge as the most important variables for bitcoin returns.
Elie Bouri, Mahamitra Das, Rangan Gupta, David Roubaud
This paper contributes to the embryonic literature on the relations between Bitcoin and conventional investments by studying return and volatility spillovers between this largest cryptocurrency and four asset classes (equities, stocks, commodities, currencies, and bonds) in bear and bull market conditions. We conducted empirical analyses based on a smooth transition VAR GARCH-in-mean model covering daily data from July 19, 2010 to October 31, 2017. We found significant evidence that Bitcoin returns are related quite closely to those of most of the other assets studies, particularly commodities, and therefore, the Bitcoin market is not isolated completely. The significance and sign of the spillovers exhibited some differences in the two market conditions and in the direction of the spillovers, with greater evidence that Bitcoin receives more volatility than it transmits. Our findings have implications for investors and fund managers who are considering Bitcoin as part of their investment strategies and for policymakers concerned about the vulnerability that Bitcoin represents to the stability of the global financial system.
The brave new world of blockchain potentially transforms the financial structures we have come to know and feel ambivalent about. What does a decentralized, secure system mean for our society?
We design a distributed platform with blockchain as a system service for supporting transaction execution in insurance processes. The insurance industry is heavily dependent on multiple processes between transacting parties for initiating, maintaining and closing diverse kind of policies. Transaction processing time, payment settlement time and security protection of the process execution are major concerns. Blockchain technology, originally conceived as an immutable distributed ledger for detecting double spending of cryptocurrencies, is now increasingly used in different FinTech systems to address productivity and security requirements. The application of blockchain in FinTech processing requires a deep understanding of the underlying business processes. It supports automated interactions between the blockchain and existing transaction systems through the notion of smart contracts. In this paper, we focus on the design of an efficient approach for processing insurance related transactions based on a blockchain-enabled platform. An experimental prototype is developed on Hyperledger fabric, an open source permissioned blockchain design framework. We discuss the main design requirements, corresponding design propositions, and encode various insurance processes as smart contracts. Extensive experiments were conducted to analyze performance of our framework and security of the proposed design.
With the recent surge in crypto-activity, a natural question arises as to what exactly a “cryptocurrency” is and how to value and assess these digital assets. In this paper, we provide an overview of the history and technology underlying cryptocurrencies. We also present information on the volume, size, and volatility of this emerging asset class, which we compare to major fiat currencies and commodities. Finally, we provide a framework for valuing crypto-assets, discuss the still-evolving regulatory environment for this asset class, and discuss the mechanics of investing in cryptocurrencies.
A. Nunez Mencias, Donna N. Dillenberger, P. Novotny, Fanni Tóth · 11 authors
Blockchain is a technology that has been available for several years and has already had several generations. Multiple implementations exist. In this paper, we describe how one of them, the Hyperledger Fabric, is used today to demonstrate the wide usage of the technology for multiple markets beyond finance and cryptocurrency. The use cases highlight the relevance of security—due to the type of data and the distributed foundation of blockchain—and of system performance to enable the use cases in production. Security and performance are the base for the architecture of blockchain on the IBM LinuxONE systems. The Secure Service Container prevents tampering, and the cryptocard usage hardens the solution—and the performance optimization in the compiler, cryptoinstructions, and large caches provides the performance. These optimizations have been further extended with the IBM z14 beyond previous IBM Z generations. In this paper, we describe how a cluster topology is used to implement a high-availability service that scales dynamically from small networks to large ones using the hot plug capabilities of the IBM LinuxONE systems.
The main objective of this investigation was to analyze the legal nature of the Decentralized Federal State as a political-territorial organization in Venezuela. The federal State is formed under the principles of federalism, that is, of political decentralization. Its territory is divided into autonomous units that, on certain matters, are governed by their own Constitution, laws and authorities, while others are subject to the central legal order of the State and the government of the federation. It corresponds to the federal Constitution to distribute the competences between the central and decentralized bodies. The methodology was based on a non-experimental design, in the documentary research modality. The techniques of documentary observation, analytical summary and critical examination, bibliographies of national and foreign authors were used; the Constitution of the Bolivarian Republic of Venezuela (1999) and the Organic Law of People's Power (2010). The techniques of data collection will be the bibliographic archival and the documentary observation, whose instrument will be the documentary record.