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.
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.
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) $O(|A|^2)$.
With development of Big Data technology these years, Internet financial companies in China started trying using big data technology to do credit investigation instead of traditional methods. But there is some limitation and problem in terms of data acquisition channel, information asymmetry and data privacy protection, etc. Block chain, characterized in unalterability and decentralization comes into people's sight. This paper will introduce block chain technology, explore the use of block chain technology in Internet financial credit investigation, and put forward an internet financial credit data sharing model based on block chain, which mainly composed by the Fin-tech Federate Servers group (FFS), the user data storage structure and a distributed database system (DDBS). By combining DPoS and re-encryption technology, the model has the characteristics of non-tampering, authorized access and convenient accountability. Through this model, the user data is recorded by the trusted agent, encrypted by asymmetric encryption technology, and anchored to the chain of the block periodically.
Siti Rohaya Mat Rahim, Zam Zuriyati Mohamad, Juliana Abu Bakar, Farhana Hanim Mohsin · 5 authors
This study examines the two important aspect of latest technology issues in Islamic finance that related to artificial intelligence (AI) and smart contract. AI refers to the ability of machines to understand, think, and learn in a similar way to human beings, indicating the possibility of using computers to simulate human intelligence. Smart contract is a computer code running on top of a block-chain containing a set of rules under which the parties to that smart contract agree to interact with each other. The main objectives of this article are to evaluate the operations of AI and smart contract, to make comparison between the operations of AI and smart contract. This article concludes that AI and smart contract will have a huge impact in future for Islamic Finance industry.
The emergence of a cryptocurrencies in the economic circulation is a challenge for legal systems. The response of a legal system depends on social, political and international determinants. The first attempts to understand cryptocurrencies usually concerns tax law, which, however, are related to the civilian understanding of the phenomenon. In the Polish legal system, we had a lack of regulation directly related to cryptocurrencies, which caused them to be strictly qualified as an instrument whose exchange for money was not exempt from VAT as Bitcoin was not classified as money. This situation has changed as a result of the case law of the Court of Justice of the European Union, which has recognized Bitcoin as an alternative means of payment. Recently, new statutory regulations have been introduced in non-European legal systems, i.e. in Japan and Arizona, which regulate cryptocurrencies in a wider way. This allows us to propose classification of legal systems based on the relationship they have towards cryptocurrencies.
Bitcoin is a peer-to-peer electronic currency without central bank controlling. Nowadays, increasing amount of people are engaged in the mining of Bitcoin for great profits. However, in the Bitcoin system, the more participants in the system, the greater computation power of the whole network and the less efficiency in the output of the coin, since large computational power of the whole Bitcoin system will lead to increased difficulty for a single miner to mine a new data block. At the same time, when more than 51% computing power is controlled by a single node, it could destroy the Bitcoin system. In order to reduce ineffective mining behaviors, one would wish to employ the optimal selection mechanism of different miners. This paper will mainly develop the model in which small miners (those who have relative smaller computational power in a block mining) join the major ones based on revenue, computational power cost, and other elements of the process comparing to the current model (when they work separately).
N.I. Indera, Ahmad Ihsan Mohd Yassin, Azlee Zabidi, Zairi Ismael Rizman
This paper presents a Multi-Layer Exogeneous Inputs (NARX) Bitcoin price forecasting model using the opening, closing, minimum and maximum past prices together with Moving Average (MA) technical indicators.
As we observe a trend towards the recentralisation of the Internet, this paper raises the question of guaranteeing an everlasting decentralisation. We introduce the properties of strong and soft uncentralisability in order to describe systems in which all authorities can be untrusted at any time without affecting the system. We link the soft uncentralisability to another property called perfect forkability. Using that knowledge, we introduce a new cryptographic primitive called uncentralisable ledger and study its properties. We use those properties to analyse what an uncentralisable ledger may offer to classic electronic voting systems and how it opens up the realm of possibilities for completely new voting mechanisms. We review a list of selected projects that implement voting systems using blockchain technol- ogy. We then conclude that the true revolutionary feature enabled by uncentralisable ledgers is a self-sovereign and distributed identity provider.
Consensus protocols inherently rely on the notion of leader election, in which one or a subset of participants are temporarily elected to authorize and announce the network's latest state. While leader election is a well studied problem, the rise of distributed ledgers (i.e., blockchains) has led to a new perspective on how to perform large-scale leader elections via solving a computationally difficult puzzle (i.e., proof of work). In this paper, we present Caucus, a large-scale leader election protocol with minimal coordination costs that does not require the computational cost of proof-of-work. We evaluate Caucus in terms of its security, using a new model for blockchain-focused leader election, before testing an implementation of Caucus on an Ethereum private network. Our experiments highlight that one variant of Caucus costs only $0.10 per leader election if deployed on Ethereum.
In this article, I shall examine the compatibility of Bitcoin and other cryptocurrencies within the context of Islamic law. I shall begin by an introduction of Bitcoin and other cryptocurrencies. I will then discuss the history of money in Islamic history, with an emphasis on the importance ethical financial dealings. I will then argue that Bitcoin and other cryptocurrencies are highly compatible within Islamic finance, and in many cases, actually provide solutions to problems of government institution controlled currencies, arguing that Bitcoin and other cryptocurrencies better address several problems that early Islamic finance scholars were concerned with. Unlike traditional fiat, the supply of Bitcoin and many other digital currencies are fixed, thereby eliminating potential for gharar (deception), and also inflation. In addition, unlike fiat and precious metal coins, digital currencies cannot be altered, forged, or manipulated. Moreover, cryptocurrencies’ peer-to-peer transactions remove the need for any banking institution, thereby eliminating any risk with a third party controlling one’s money. I shall then conclude with a summary of the main points of the article, and examine future possibilities with regards to the role of digital and cryptocurrencies.
We present a formalization of blockchain as a state machine, focusing upon permissionless blockchains due to general audience awareness of its most popular implementation, Bitcoin (permissioned blockchains are treated similarly without loss of generality). After presenting a typical Bitcoin transaction workflow, a general blockchain state representation is derived. It is demonstrated that the proper mathematical object defining the state of a blockchain is a topological fiber bundle, because it is not possible to globally `parametrize' blocks (or ledgers of blocks) by time due to their dependence upon cryptographic hash functions. In addition, we specify a general transition function between blockchain states that is agnostic to the consensus mechanism used to write blocks into the ledger, and which is probabilistic in nature, so that blockchain may be regarded as a probabilistic state machine. We then interpret agents (both human and code-based, such as `chaincode', `smart contracts', or other artificial intelligence) as automata interacting with blockchain technology, drawing upon the theory of non-cooperative repeated interaction games. Finally, blockchain as a hierarchy of state machines is defined, and future research directions are presented using this hierarchy as a point of departure for modeling blockchain dynamics.
Hélder Sebastião, António Portugal Duarte, Gabriel Guerreiro
This paper analyses the price discovery in the USD/Bitcoin market since Mar‑2014 to Nov‑2016. The results show a positive relationship between the informational relevance of exchanges and their market shares. Information is mostly transmitted between exchanges within an hour, at least for the main exchanges, although lagged feedbacks occur from the major exchanges. Minor exchanges are merely satellite ones and react to price information with some delay. Bitfinex is the most important exchange: the lagged feedback from this exchange to the market is 18.3%, while the reverse feedback accounts only for 0.6% of the total feedback. Volatility in the major exchanges is the main factor explaining the feedback measures, which sustains the claim that the relative importance of the information-based component of volatility increases with the relative dimension of the exchange.
Husam Al Jawaheri, Mashael Al Sabah, Yazan Boshmaf, Aiman Erbad
With the rapid increase of threats on the Internet, people are continuously seeking privacy and anonymity. Services such as Bitcoin and Tor were introduced to provide anonymity for online transactions and Web browsing. Due to its pseudonymity model, Bitcoin lacks retroactive operational security, which means historical pieces of information could be used to identify a certain user. We investigate the feasibility of deanonymizing users of Tor hidden services who rely on Bitcoin as a payment method by exploiting public information leaked from online social networks, the Blockchain, and onion websites. This, for example, allows an adversary to link a user with @alice Twitter address to a Tor hidden service with private.onion address by finding at least one past transaction in the Blockchain that involves their publicly declared Bitcoin addresses.
To demonstrate the feasibility of this deanonymization attack, we carried out a real-world experiment simulating a passive, limited adversary. We crawled 1.5K hidden services and collected 88 unique Bitcoin addresses. We then crawled 5B tweets and 1M BitcoinTalk forum pages and collected 4.2K and 41K unique Bitcoin addresses, respectively. Each user address was associated with an online identity along with its public profile information. By analyzing the transactions in the Blockchain, we were able to link 125 unique users to 20 Tor hidden services, including sensitive ones, such as The Pirate Bay and Silk Road. We also analyzed two case studies in detail to demonstrate the implications of the resulting information leakage on user anonymity. In particular, we confirm that Bitcoin addresses should always be considered exploitable, as they can be used to deanonymize users retroactively. This is especially important for Tor hidden service users who actively seek and expect privacy and anonymity.
Blockchains enables tamper-proof, ordered logging for transactional data in a decentralized manner over open-access, overlay peer-to-peer networks. In this paper, we propose a decentralized framework of proactive caching in a hierarchical wireless network based on blockchains. We employ the blockchain-based smart contracts to construct an autonomous content caching market. In the market, the cache helpers are able to autonomously adapt their caching strategies according to the market statistics obtained from the blockchain, and the truthfulness of trustless nodes are financially enforced by smart contract terms. Further, we propose an incentive-compatible consensus mechanism based on proof-of-stake to financially encourage the cache helpers to stay active in service. We model the interaction between the cache helpers and the content providers as a Chinese restaurant game. Based on the theoretical analysis regarding the Nash equilibrium of the game, we propose a decentralized strategy-searching algorithm using sequential best response. The simulation results demonstrate both the efficiency and reliability of the proposed equilibrium searching algorithm.