Peng Zhang, Jules White, Douglas C. Schmidt, Gunther Lenz
Since the inception of the Bitcoin technology, its underlying data structure--the blockchain--has garnered much attention due to properties such as decentralization, transparency, and immutability. These properties make blockchains suitable for apps that require disintermediation through trustless exchange, consistent and incorruptible transaction records, and operational models beyond cryptocurrency. In particular, blockchain and its smart contract capabilities have the potential to address healthcare interoperability issues, such as enabling effective interactions between users and medical applications, delivering patient data securely to a variety of organizations and devices, and improving the overall efficiency of medical practice workflow. Despite the interest in using blockchain for healthcare interoperability, however, little information is available on the concrete architectural styles and patterns for applying blockchain to healthcare apps. This paper provides an initial step in filling this gap by showing: (1) the features and implementation challenges in healthcare interoperability, (2) an end-to-end case study of a blockchain-based healthcare app we are developing, and (3) how applying foundational software patterns can help address common interoperability challenges faced by blockchain-based healthcare apps.
Mauro Conti, E. Sandeep Kumar, Chhagan Lal, Sushmita Ruj
Bitcoin is a popular cryptocurrency that records all transactions in a distributed append-only public ledger called blockchain. The security of Bitcoin heavily relies on the incentive-compatible proof-of-work (PoW) based distributed consensus protocol, which is run by the network nodes called miners. In exchange for the incentive, the miners are expected to maintain the blockchain honestly. Since its launch in 2009, Bitcoin economy has grown at an enormous rate, and it is now worth about 150 billions of dollars. This exponential growth in the market value of bitcoins motivate adversaries to exploit weaknesses for profit, and researchers to discover new vulnerabilities in the system, propose countermeasures, and predict upcoming trends. In this paper, we present a systematic survey that covers the security and privacy aspects of Bitcoin. We start by giving an overview of the Bitcoin system and its major components along with their functionality and interactions within the system. We review the existing vulnerabilities in Bitcoin and its major underlying technologies such as blockchain and PoW-based consensus protocol. These vulnerabilities lead to the execution of various security threats to the standard functionality of Bitcoin. We then investigate the feasibility and robustness of the state-of-the-art security solutions. Additionally, we discuss the current anonymity considerations in Bitcoin and the privacy-related threats to Bitcoin users along with the analysis of the existing privacy-preserving solutions. Finally, we summarize the critical open challenges, and we suggest directions for future research towards provisioning stringent security and privacy solutions for Bitcoin.
Open access
3 source records
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Manuscript submission systems are a central fixture in scholarly publishing. However, with existing systems, researchers must trust that their yet unpublished findings will not prematurely be disseminated due to technical weaknesses and that anonymous peer reviewers or committee members will not plagiarize unpublished content. To address this limitation, we present CryptSubmit - a system that automatically creates a decentralized, tamperproof, and publicly verifiable timestamp for each submitted manuscript by utilizing the blockchain of the cryptocurrency Bitcoin. The publicly accessible and tamperproof infrastructure of the blockchain allows researchers to independently verify the validity of the timestamp associated with their manuscript at the time of submission to a conference or journal. Our system supports researchers in protecting their intellectual property even in the face of vulnerable submission platforms or dishonest peer reviewers. Optionally, the system also generates trusted timestamps for the feedback shared by peer reviewers to increase the traceability of ideas. CryptSubmit integrates these features into the open source conference management system OJS. In the future, the method could be integrated at nearly no overhead cost into other manuscript submission systems, such as EasyChair, ConfTool, or Ambra. The introduced method can also improve electronic pre-print services and storage systems for research data.
Present paper explains role of the Bitcoin and its involvement in economic activity worldwide, using practical examples of real business models, reflects the modern views of legislators and judicial bodies on local (selective countries legislation and court practice) and international level (European Union legislation and international court practice), which are formed after Bitcoinâs fast widespread in 2012. Current research examines in details various definition of the Bitcoin, used by legislators to place Bitcoin in already existing legal frames â virtual money, property, commodity or financial instruments, which has significant importance to legislators worldwide to regulate business activity related to Bitcoin: licensing of institutions issuing Bitcoin, if it is defined as virtual money; Bitcoinâs place in stock market, if it is defined as security or financial instrument; or transfer of property rights, if Bitcoin is defined as commodity or property. Moreover this paper underlines importance of amendments acceptance, based on certain Bitcoinâs definition, to prevent money laundering, financial support providing to terrorism, to straighten financial market and consumer protection procedures.
Thomas Lundqvist, Andreas de Blanche, H. Robert H. Andersson
Thing-to-thing payments are a key enabler in the Internet of Things (IoT) era, to ubiquitously allow for devices to pay each other for services without any human interaction. Traditional credit card-based systems are not able to handle this new paradigm, however blockchain technology is a promising payment candidate in this context. The prominent example of blockchain technology is Bitcoin, with its decentralized structure and ease of account creation. This paper presents a proof-of-concept implementation of a smart cable that connects to a smart socket and without any human interaction pays for electricity. In this paper, we identify several obstacles for the widespread use of bitcoins in thing-to-thing payments. A critical problem is the high transaction fees in the Bitcoin network when doing micro transactions. To reduce this impact, we present a single-fee micro-payment protocol that aggregates multiple smaller payments incrementally into one larger transaction needing only one transaction fee. The proof-of concept shows that trustless, autonomous, and ubiquitous thing-to-thing micro-payments is no longer a future technology.
We present the first measurement study of JoinMarket, a growing marketplace for more anonymous transfers in the Bitcoin ecosystem. Our study reveals that this market is funded with multiple thousand bitcoins and generated a turnover of almost 29.5 million USD over the course of 13 months. Assessing the resilience of the market against a well-funded attacker, we discover that in a typical scenario, a selective attack with a 90% success rate requires an investment of 14 000â54 000 USD (which is recoverable after the attack). We present economic arguments to explain the existence of this novel market for anonymity and underpin the hypothesis of heterogeneous time preference with empirical data.
We investigate how distributed denial-of-service (DDoS) attacks and other disruptions affect the Bitcoin ecosystem. In particular, we investigate the impact of shocks on trading activity at the leading Mt. Gox exchange between April 2011 and November 2013. We find that following DDoS attacks on Mt. Gox, the number of large trades on the exchange fell sharply. In particular, the distribution of the daily trading volume becomes less skewed (fewer big trades) and had smaller kurtosis on days following DDoS attacks. The results are robust to alternative specifications, as well as to restricting the data to activity prior to March 2013, i.e., the period before the first large appreciation in the price of and attention paid to Bitcoin.
Tareq Ahram, Arman Sargolzaei, Saman Sargolzaei, Jeff Daniels · 5 authors
Digital world has produced efficiencies, new innovative products, and close customer relationships globally by the effective use of mobile, IoT (Internet of Things), social media, analytics and cloud technology to generate models for better decisions. Blockchain is recently introduced and revolutionizing the digital world bringing a new perspective to security, resiliency and efficiency of systems. While initially popularized by Bitcoin, Blockchain is much more than a foundation for crypto currency. It offers a secure way to exchange any kind of good, service, or transaction. Industrial growth increasingly depends on trusted partnerships; but increasing regulation, cybercrime and fraud are inhibiting expansion. To address these challenges, Blockchain will enable more agile value chains, faster product innovations, closer customer relationships, and quicker integration with the IoT and cloud technology. Further Blockchain provides a lower cost of trade with a trusted contract monitored without intervention from third parties who may not add direct value. It facilitates smart contracts, engagements, and agreements with inherent, robust cyber security features. This paper is an effort to break the ground for presenting and demonstrating the use of Blockchain technology in multiple industrial applications. A healthcare industry application, Healthchain, is formalized and developed on the foundation of Blockchain using IBM Blockchain initiative. The concepts are transferable to a wide range of industries as finance, government and manufacturing where security, scalability and efficiency must meet.
Blockchain, which is the backbone of Bitcoin, has recently received a lot of attention. Blockchain functions as an immutable ledger that enables decentralized transactions. Numerous fields, such as the Internet of Things (IoT), reputation systems, and financial services, are being covered by blockchain-based applications. However, blockchain technology still faces numerous difficulties, such as scalability and security issues, that need to be resolved. A comprehensive overview of blockchain technology is provided in this paper. First, we compare some common consensus algorithms utilized by various blockchains and provide an overview of the architecture of blockchains. In addition, a brief list of recent advancements and technical difficulties is provided. In addition, we outline potential blockchain trends for the future.
In the absence to date of any specific pre-emptive federal regulation of blockchain distributed ledger technology in fintech, smart contracts, or other uses, this paper discusses early state legislation including Arizona, California, Delaware, Hawaii, Illinois, Maine, New York, Nevada and Vermont. While the list comprises usual suspects for early adoption of disruptive technology regulation, especially of its real-time aspects that were recognized in In re Dole Food Co (Del. Ch. Feb. 15, 2017), the mechanics of blockchain are still evolving and restrictive regulations appear both premature and at risk of expedited obsolescence. Before expanding to general record-keeping transactions, blockchain was first used in bitcoin, a virtual currency. Then, blockchain evolved towards self-executing smart contracts using ethereum technology and may eventually reach an âInternet of Agreements.â While its promise for applications like virtual currencies and payments is obvious and vigorously explored by major financial institutions, blockchainâs real strength lies in authentication and keeping records up-to-date, especially for valuable, highly liquid assets like securities. Key developments for blockchainâs regulation and implementation in an evidentiary context occurred in Arizona (recognition of smart contracts), Vermont (blockchain as evidence), Chicago (real estate records), and, most importantly, Delaware (pending initiative authorizing registration of shares of Delaware companies in blockchain form). Since 64 percent of Fortune 500 companies and over 1 million entities are incorporated in Delaware, an enactment of Delawareâs initiative will change regulatory landscape for securities by setting precedent in the most important corporate jurisdiction of the U.S. Other states competing for corporate taxes and fees would be sure to follow.
The paper investigates the Bitcoin exchange rate response to the dai- ly Twitter data. Sentiment score is computed for the number of obtained tweets. The prediction accuracy for the Bitcoin exchange rate employing the sentiment score reveals the influence of the Twitter social network on the news diffusion and target exchange rate volatility. We used the historical data on the Bitcoin exchange rate and the daily sentiment score of the pertinent tweets to forecast the direction of change for the Bitcoin. The results show better performance of the developed forecasting method with both historical data on the exchange rate and the sentiment score than using only the exchange rate data as an input.
This article demonstrates the possibility of constructing indicators of critical and crisis phenomena in the volatile market of cryptocurrency. For this purpose, the methods of the theory of complex systems such as recurrent analysis of dynamic systems and the calculation of permutation entropy are used. It is shown that it is possible to construct dynamic measures of complexity, both recurrent and entropy, which behave in a proper way during actual pre-crisis periods. This fact is used to build predictors of crisis phenomena on the example of the main five crises recorded in the time series of the key cryptocurrency bitcoin, the effectiveness of the proposed indicators-precursors of crises has been identified.
A. Seetharaman, A. Saravanan, Nitin Patwa, Jigar Mehta
In an era of technology advancement when the entire world is talking about the âInternet of Thingsâ whereby we are expected to have connectivity between anything and everything, Currency cannot be left behind. Paper currency is bound to be a thing of past, as virtual currencies will start taking over and Bitcoin is well poised to achieve this feat. Not only it will revolutionize the way payments are made, but also have potential to impact the future of world currencies like USD, which is already facing challenges from EURO or Chinese Yuan Renminbi (CNY). The rise of crypto-currencies will add a new dimension to this challenge for US Dollar (USD)The focus of this study is to understand multiple factors which are translating Bitcoin (BTC) that is gaining momentum in various fields of global finance and how disruptive it can be, including replacing main fiat currencies in the financial system impacting mainly USD. The key variables studied are Regulation or lack of it around Bitcoin, Bitcoin Technology, Bitcoin Economy and the usage of Bitcoin as a Currency. This research used the latest statistical tool ADANCO 1.1.1 by Henseler and Dijkstra (2015) to analyze the data collected by building a partial least squares structural equation model (PLS-SEM). The observations of this study will help understand the future of global finance from multiple standpoints, especially Regulation, Cryptocurrencies and the fiat currencies.
This work show an avaliation about the performance of the application of Group Signature technique in Bitcoin system and a study about the anonymity and auditory. The Bitcoinâ goal is provide a virtual currency and an anonymous online transaction system. However, recent researches show that can be to break the anonymity of transactions through the chronological traceability technique in the Bitcoin transactions and analysis of network addresses. As a result of breaking anonymity of Bitcoin transactions, usersâ privacy and all Bitcoin ecosystem are affected negatively. For this reason, in this work, it was proposed to include Group Signatures techniques in the Bitcoin system to increasing of anonymity in Bitcoin transactions but with audity possibility in accept time, more or less 10 minutes. The Group Signature generate a lot of dinstinct groups to dinstinct Bitcoin transactions. After to include the Group Signature technique in a modified version of Bitcoin system, we evaluated this technique in Bitcoin system through experiment in simulations. Through the experiments and statistic analysis, it was found that the approach of including the Group Signature is feasible for implementation in Bitcoin system with small groups, 500 clients. For the all cases analyzed, it was verified that the use of Group Signature in Bitcoin transactions increase the anonymity. Therefore, it was verified that the performance of Bitcoin transactions with Group Signature technique show a delay in nearly 50% less than current Bitcoin system whitout this technique. Nevertheless, in small groups with Group Signature get a better anonymity level and audity, but in big groups with more than 500 clients this technique not is good because the transactions time is over.
The trend of digital currencies is catching fire these days, more and more people want to use digital currency. When we talk about digital currencies then how can we forget taking the name of Cryptocurrencies like Bitcoin. These currencies because of their P2P nature have won lot of hearts. You must have heard that "Every Rose has a thorn", similar type of thing is with Cryptocurrencies too. Because of the reason these currencies are P2P nature and there is no 3rd party who controls these cryptocurrencies, these are being used for illegal drugsarms dealing and for purchasing weapons online which are used in the terror attacks. We have found out a solution in order to put an end to it and the solution is Freezing of Assets. In this the owner will have the liberty to freeze any account whichever seem fishy and the freezed accounts will have their money intact, just the difference will be that they won't be able to transfer the money.
Abeer ElBahrawy, Laura Alessandretti, Anne Kandler, Romualdo PastorâSatorras · 5 authors
The cryptocurrency market surpassed the barrier of \$100 billion market capitalization in June 2017, after months of steady growth. Despite its increasing relevance in the financial world, however, a comprehensive analysis of the whole system is still lacking, as most studies have focused exclusively on the behaviour of one (Bitcoin) or few cryptocurrencies. Here, we consider the history of the entire market and analyse the behaviour of 1,469 cryptocurrencies introduced between April 2013 and June 2017. We reveal that, while new cryptocurrencies appear and disappear continuously and their market capitalization is increasing (super-)exponentially, several statistical properties of the market have been stable for years. These include the number of active cryptocurrencies, the market share distribution and the turnover of cryptocurrencies. Adopting an ecological perspective, we show that the so-called neutral model of evolution is able to reproduce a number of key empirical observations, despite its simplicity and the assumption of no selective advantage of one cryptocurrency over another. Our results shed light on the properties of the cryptocurrency market and establish a first formal link between ecological modelling and the study of this growing system. We anticipate they will spark further research in this direction.
While online services emerge in all areas of life, the voting procedure in many democracies remains paper-based as the security of current online voting technology is highly disputed. We address the issue of trustworthy online voting protocols and recall therefore their security concepts with its trust assumptions. Inspired by the Bitcoin protocol, the prospects of distributed online voting protocols are analysed. No trusted authority is assumed to ensure ballot secrecy. Further, the integrity of the voting is enforced by all voters themselves and without a weakest link, the protocol becomes more robust. We introduce a taxonomy of notions of distribution in online voting protocols that we apply on selected online voting protocols. Accordingly, blockchain-based protocols seem to be promising for online voting due to their similarity with paper-based protocols.
Youngbin Kim, Jurim Lee, Nuri Park, Jaegul Choo · 6 authors
Bitcoin is an online currency that is used worldwide to make online payments. It has consequently become an investment vehicle in itself and is traded in a way similar to other open currencies. The ability to predict the price fluctuation of Bitcoin would therefore facilitate future investment and payment decisions. In order to predict the price fluctuation of Bitcoin, we analyse the comments posted in the Bitcoin online forum. Unlike most research on Bitcoin-related online forums, which is limited to simple sentiment analysis and does not pay sufficient attention to note-worthy user comments, our approach involved extracting keywords from Bitcoin-related user comments posted on the online forum with the aim of analytically predicting the price and extent of transaction fluctuation of the currency. The effectiveness of the proposed method is validated based on Bitcoin online forum data ranging over a period of 2.8 years from December 2013 to September 2016.
In recent years a new type of tradable assets appeared, generically known as cryptocurrencies. Among them, the most widespread is Bitcoin. Given its novelty, this paper investigates some statistical properties of the Bitcoin market. This study compares Bitcoin and standard currencies dynamics and focuses on the analysis of returns at different time scales. We test the presence of long memory in return time series from 2011 to 2017, using transaction data from one Bitcoin platform. We compute the Hurst exponent by means of the Detrended Fluctuation Analysis method, using a sliding window in order to measure long range dependence. We detect that Hurst exponents changes significantly during the first years of existence of Bitcoin, tending to stabilize in recent times. Additionally, multiscale analysis shows a similar behavior of the Hurst exponent, implying a self-similar process.
Bitcoin is a cryptocurrency which has received increasing interest over the last five years. Built upon a decentralized peer to peer system, it supports transparent, fast, cost effective, and irreversible transactions, without the need for trusting third party financial institutions. We know however little about people's motivation and experience with bitcoin currency. This paper reports on interviews with 20 bitcoin users in Malaysia about their experience and trust challenges. Findings show that bitcoins are used more as store of value for speculative investment or savings' protection. The paper advances the HCI theories on trust by identifying main bitcoin characteristics and their impact on trust, such as decentralization, unregulation, embedded expertise, and reputation, as well as transactions' transparency, low cost, and easiness to complete. We discuss insecure transactions, the risk of dishonest traders and its mitigating strategies. The paper concludes with design implications including support for the transparency of two-way transactions, tools for materializing trust, and tools for supporting reversible transactions.
The emergence of a cryptocurrency in the digital domain went unnoticed for years until the general press started to cover Bitcoin's more than tenfold raise in price in the space of a few months in 2017. Earlier on, technical and legal discussion revolved around one of its fundamental building blocks, but Bitcoin is more than the blockchain or an investment object. It is a revolutionary open source artefact that is bound to change the way we consider currency, as well as a proof-of-concept for how parts of international trade could disfranchise banks and other institutions as payment service providers.