Mikael Asplund, Jakob Lövhall, Simin Nadjm‐Tehrani
The possibility of in-store payments would further increase the potential usefulness of cryptocurrencies. However, this would require much faster transaction verification than current solutions provide (one hour for Bitcoin) since customers are likely not prepared to wait a very long time for their purchase to be accepted by a store. We propose a solution for enabling in-store payments with waiting times in the order of a few seconds, which is still compatible with the current Bitcoin protocol. The idea is based on a payment card in combination with a protocol for ensuring that losing a card does not mean losing the money on it. We analyse the required transaction verification delay and also the potentially added risks that the solution brings compared to current systems.
Open access
Blockchain Technology Applications and Security
IoT and Edge/Fog Computing
Advanced Steganography and Watermarking Techniques
Eventhough Ethiopia is investing a lot in electricity generation and infrastructure, the electricity access rate in the country is one of the lowest in Africa mainly due to inadequate expansion of electricity connection in rural areas. The purpose of this study was to assess the key challenges and the prospect of electricity access in the country and to recommend the way forward to address the electricity access gap. This study mainly used secondary data collected from extensively reviewed documents and also interviews with purposely selected experts and officials to substantiate the findings. According to the findings of this research, the electricity access programs of the country were not effective to meet the electricity access gap. The institutional instability of the sector, less attention to decentralized or off-grid electricity access programs ,lack of financing and private sector engagement have been some of the challenges hindering the enhancement of electricity access in the country. Therefore, establishing a long term and stable institutional structure in the electricity sector, strengthening and expanding decentralized (off-grid) electrification programs, setting a cost reflective electricity tariff (both for local and export) for the sector's sustainability and enhancing the private sector engagement are some of the recommendations of this study to reach the universal electricity access targets of the country
This piece of work is aimed at arguing the advantages and disadvantages as well as the challenges of the blockchain technology and if this distributed ledger system, has the potential to replace current regulatory bodies and intermediaries in the financial services sector, specifically in terms of identity management and more generally. This would seem to have been the vision of the originators of the technology back in 2009/10. To create a self-sustainable, secure environment for transactions of monetary nature. In this piece of work, it is the intention to follow a specific argument in order to demonstrate that this “original idea” is not something which is likely to survive or become main stream. Rather, arguments will be made to demonstrate that likely there will be a hybrid of “old” and “new” emerging. The solution suggested to harvest the full potential of those new emerging technologies, amongst others, customer identity management, is to streamline existing processes by involving regulatory bodies in the process of setting up new services for transacting and managing identities, as the need for oversight, due to technological flaws, cannot be argued away completely.
In the Internet economy, with the help of cryptography, a branch of mathematics dealing with the security of information, as well as authentication and restriction of access to a computer system, a new digital coin as an alternative to national currencies appeared. In accomplishing this, using both mathematical methods (taking advantage of, for example, the difficulty of factorizing very large numbers), and quantum encryption methods. Throughout the world, information technology companies are focusing on information protection, inventing day-to-day methods with greater durability. In the horizon of Information Security, Quantum Cryptography has emerged, generating new possibilities in that field, hoping that data will be better protected and that the digital currency will resist over time and eventually evolve in the future, although Kurzweil, Bitcoin's pioneering technology is unlikely to be used in this respect. The idea of virtual alternatives to national currencies is not new, with advantages and disadvantages. The advantages of this coin are high payment freedom, transparency of information, high security, reduced risks for traders. Among the disadvantages we highlight the risk and volatility, the lack of notification and understanding, with incomplete functions, but which are developing, so Bitcoin is not perfect.
Long Finance's Distributed Futures research programme is pleased to announce the launch the report “The Quantum Countdown: Quantum Computing & The Future Of Distributed Ledger Encryption”, another in a series of exciting projects in the programme.
Smart Ledgers are based on a combination of mutual distributed ledgers (aka block-chain: multi-organisational databases with a super audit trail) with embedded programming and sensing, thus permitting semi-intelligent, autonomous transactions. Smart Ledgers are touted as a technology for fair play in a globalized world. There are numerous projects building trade systems using this technology with announcements from governments, shipping firms, large IT firms, and the like. The research is intended to inform policy makers and business people making decisions about moving towards these systems.
This report is about a major threat to the security of Smart Ledgers and other systems from quantum computing. If and when large-scale quantum computers become available, there is a concern that such computers would be able to break the security of widely-used public key cryptography, which allows remote parties to communicate securely and authenticate transactions and data without sharing a secret key in advance. Fortunately, there are good solutions to this problem, and better ones are emerging. The hard questions for individual computer system operators involve when and how to address the problem, given its uncertain timing and the evolving solutions. The report seeks to explain the problem in detail for both non-technical and technical readers, starting with the essentials of cryptography, quantum computing, and how quantum computing threatens public key cryptography. It then considers the available solutions to the problem, and provides frameworks for deciding when and how to respond to it.
Smart contracts gain rapid exposure since the inception of blockchain<br/>technology. Today's smart contracts are coded in non-mainstream<br/>procedural programming languages (e.g. Solidity for Ethereum),<br/>which lifts the requirement to draft enterprise ready smart contract to<br/>both a legal professional and a programmer instead of only the former.<br/>In search for a smart contract language that reduces the threshold to<br/>draft one, this conceptual paper elaborates how business logic can be<br/>converted to executable code for commitment-based smart contracts.<br/>Hereby, a contract is viewed as a set of reciprocal commitments. The<br/>smart contract ensures the automated execution of all or most of these<br/>commitments. In order to leverage its event processing capabilities,<br/>Reaction RuleML has been used to appropriately represent the<br/>elements and working of passive and active rules within a<br/>commitment based smart.
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.
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.
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.
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.
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?
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.
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.
PETER MWIATHI SILAS, Nelson Wawire, Perez Ayieko Onono-Okelo
The Kenya government has instituted fiscal decentralization over the years to promote social economic development, reduce poverty and income inequality and ensure balanced regional development. Despite these efforts, poverty levels have remained high in Kenya. The literature on the relationship between fiscal decentralization and poverty has been rather inconclusive about the effects of fiscal decentralization on poverty. The main objective of this paper was to analyse the effects of fiscal decentralization on poverty in Kenya. Using cross-county panel data from 2002 – 2014 and published data from government agencies, UNDP reports and World Bank reports, the paper estimated various empirical models to analyse the effects intergovernmental transfers, sub-national own-source revenue and county expenditure on poverty in Kenya. The study established that the effect of fiscal decentralization on poverty depends on the nature of decentralization and the extent of fiscal decentralization as well as the county specifics. The paper therefore, recommends the need for for county governments to have adequate own-source revenue to finance their expenditure as opposed to relying on intergovernmental transfers from national government.
Cryptocurrencies are a type of digital currencies that are relying on cryptographic proofs for confirmation of transactions. Cryptocurrencies usually achieve a unique combination of three features: ensuring limited anonymity, independence from central authority and double spending attack protection. No other group of currencies, including fiat currencies, has this combination of features. We will define cryptocurrency ownership and account anonymity. We will define cryptocurrency ownership and account anonymity. We will introduce a classification of the types of approaches to regulation of cryptocurrencies by various individual countries. We will present the risks that the use of cryptocurrencies involves and the possibilities of prevention of those risks. We will present the possible use of cryptocurrencies for the benefit of the state. The conclusion addresses the implications of adoption of a cryptocurrency as a national currency.
Digital banking as an essential service can be hard to access in remote, rural regions where the network connectivity is unavailable or intermittent. The payment operators like Visa and Mastercard often face difficulties reaching these remote, rural areas. Although micro-banking has been made possible by short message service or unstructured supplementary service data messages in some places, their security flaws and session-based nature prevent them from wider adoption. Global-level cryptocurrencies enable low-cost, secure, and pervasive money transferring among distributed peers, but are still limited in their ability to reach people in remote communities. We propose a blockchain-based digital payment scheme that can deliver reliable services on top of unreliable networks in remote regions. We focus on a scenario where a community-run base station provides reliable local network connectivity while intermittently connects to the broader Internet. We take advantage of the distributed verification guarantees of the Blockchain technology for financial transaction verification and leverage smart contracts for secure service management. In the proposed system, payment operators deploy multiple proxy nodes that are intermittently connected to the remote communities where the local blockchain networks, such as Ethereum are composed of miners, vendors, and regular users. Through probabilistic modeling, we devise design parameters for the blockchain network to realize robust operation over the top of the unreliable network. Furthermore, we show that the transaction processing time will not be significantly impacted due to the network unreliability through extensive emulations on a private Ethereum network. Finally, we demonstrate the practical feasibility of the proposed system by developing Near Field Communication (NFC)-enabled payment gateways on Raspberry-Pis, a mobile wallet application and mining nodes on off-the-shelf computers.
Els conceptes de cadenes de blocs (blockchains) i contractes intel·ligents (smart contracts) ofereixen una alternativa sostenible en educació superior. Des d’aquest objectiu, es presenta una revisió d’ambdós conceptes i la seva relació amb els termes bitcoin, ledger, edublock i educoin. En un segon moment, s’atén a les xarxes en educació superior basades en tecnologia de cadenes de blocs, el seu vincle amb els contractes intel·ligents i les possibilitats a dia d’avui.
Elli Androulaki, Artem Barger, Vita Bortnikov, Christian Cachin · 21 authors
Fabric is a modular and extensible open-source system for deploying and operating permissioned blockchains and one of the Hyperledger projects hosted by the Linux Foundation (www.hyperledger.org). Fabric is the first truly extensible blockchain system for running distributed applications. It supports modular consensus protocols, which allows the system to be tailored to particular use cases and trust models. Fabric is also the first blockchain system that runs distributed applications written in standard, general-purpose programming languages, without systemic dependency on a native cryptocurrency. This stands in sharp contrast to existing blockchain platforms that require "smart-contracts" to be written in domain-specific languages or rely on a cryptocurrency. Fabric realizes the permissioned model using a portable notion of membership, which may be integrated with industry-standard identity management. To support such flexibility, Fabric introduces an entirely novel blockchain design and revamps the way blockchains cope with non-determinism, resource exhaustion, and performance attacks. This paper describes Fabric, its architecture, the rationale behind various design decisions, its most prominent implementation aspects, as well as its distributed application programming model. We further evaluate Fabric by implementing and benchmarking a Bitcoin-inspired digital currency. We show that Fabric achieves end-to-end throughput of more than 3500 transactions per second in certain popular deployment configurations, with sub-second latency, scaling well to over 100 peers.
Permission-less blockchains can realise trustless trust, albeit at the cost of limiting the complexity of computation tasks. To explain the implications for scalability, we have implemented a trust model for smart contracts, described as agents in an open multi-agent system. Agent intentions are not necessarily known and autonomous agents have to be able to make decisions under risk. The ramifications of these general conditions for scalability are analysed for Ethereum and then generalised to other current and future platforms.
An atomic cross-chain swap is a distributed coordination task where multiple parties exchange assets across multiple blockchains, for example, trading bitcoin for ether. An atomic swap protocol guarantees (1) if all parties conform to the protocol, then all swaps take place, (2) if some coalition deviates from the protocol, then no conforming party ends up worse off, and (3) no coalition has an incentive to deviate from the protocol. A cross-chain swap is modeled as a directed graph ${\cal D}$, whose vertexes are parties and whose arcs are proposed asset transfers. For any pair $({\cal D},L)$, where ${\cal D} = (V,A)$ is a strongly-connected directed graph and $L \subset V$ a feedback vertex set for ${\cal D}$, we give an atomic cross-chain swap protocol for ${\cal D}$, using a form of hashed timelock contracts, where the vertexes in $L$ generate the hashlocked secrets. We show that no such protocol is possible if ${\cal D}$ is not strongly connected, or if ${\cal D}$ is strongly connected but $L$ is not a feedback vertex set. The protocol has time complexity $O(diam({\cal D}))$ and space complexity (bits stored on all blockchains) $O(|A|^2)$.