Bitcoin has emerged as the leading cryptographic currency since its inception in 2009 and at the time of writing holds a market capitalization of $28.4 billion. This ever-increasing figure has attracted adopters seeking to advance their investments, often leaving purely technical aspects on the sidelines. As is the case with any innovative technology, misconceptions are plentiful and information is not always conclusive. The research effort presented in this paper consists of a quantitative study seeking to address the subject of user anonymity in the Bitcoin network by employing an online survey on one of the most prominent Bitcoin forums. This includes 50 eligible participants, whose motivation is derived through the application of temporal motivation theory. The survey seeks to form an understanding of user attitudes towards the aspect of anonymity by following a methodological approach for exploring common tendencies among the representatives and will serve as the underlying data set from which conclusions can be drawn. Furthermore, this paper will present a literary study of the actual state of anonymity in this peer-to-peer technology by reviewing current findings highlighted in the area, thus presenting a comprehensive view of anonymity in the Bitcoin network, which will contrast the user study.
Octavian Nica, Karolina Piotrowska, Klaus Reiner Schenk–Hoppé
Since the creation of Bitcoin in 2009, hundreds of cryptocurrencies have emerged, thus becoming a common fixture of financial news bulletins. With a market capitalization of the five highest-valued cryptocurrencies exceeding $140 billion at the time of writing, these alternative currencies have caught the attention of both financial institutions and central banks with their innovative technological foundations and their potential to disrupt current financial institutional structures. We provide a non-technical overview of the concept and current market structure of cryptocurrencies for researchers in economics, finance, mathematics and computer science.
Bitcoin volatility is known to be high, as is shown by comparing Bitcoin volatility to several currencies and to assets like stock, gold etc. This work attempts to extend this work by comparing Bitcoin volatility to volatility of currencies of least developed countries and other cryptocurrencies. Exchange rate and return data drawn from Bloomberg and covering March 2014 to March 2017 was analysed. It was found that Bitcoin volatility is still considerably higher than volatilities of currencies of least developed countries. Only five currencies were more volatile for more than 10% of the time span analysed.
Blockchain technology is a system of creating an immutable, secure, distributed database of transactions. Blockchains were initially created to provide a distributed ledger of financial transactions that did not rely upon a central bank, credit company, or other financial institution. The technological breakthrough, however, has been extended to transactions involving legal matters, medical records, insurance billing, and smart contracts. One primary way that blockchain technology is important to healthcare professionals in that it can revolutionize medical database interoperability. This greater interoperability can help improve access to medical records, imaging archives, prescription databases. Given that a patient’s medical history is a primary cornerstone of good medicine, blockchain technology has the potential to dramatically improve medical care.
Open access
2 source records
Electronic Health Records Systems
Artificial Intelligence in Healthcare and Education
Felipe de Oliveira Simoyama, Ian Grigg, Ricardo Luiz Pereira Bueno, Ludmila Cavarzere De Oliveira
Legislation generally requires public agencies to account for their activity to the public. Among the many duties imposed by legislatures around the world are requirements for transparency in procurement of services, budgeting and presentation of accounts. However, agencies in countries with high corruption problems have trouble complying with the legislation, especially in smaller agencies. Moreover, it is typically infeasible for national auditors to audit all the accounts rendered, and instead, they select a small sample for audit based on their level of risk. Another problem is that the presentation of accounts occurs once a year for all agencies, leading to a seasonal demand with significant lag time between auditing and accounting period. In this study, we present a non-technical framework based on the emerging technology of blockchain that could be a solution to all these concerns. We apply it within the context of Brazilian legislation and the Federal Court of Accounts of Brazil (TCU), although the proposal is applicable across a wide range of countries facing severe corruption.
In spite of a still very low volume at the global level, in comparison with the main reserve currencies, digital currencies attract a lot of attention. The paper reminds that it is above all the exchange mechanism incorporated in digital currencies (the distributed ledger technology) which should contribute to their success. It is shown that a widespread use of these currencies is likely to materialize only under conditions that woulDeessentially leave unchanged the capacity of the central bank to pursue the same inflation target using the same instruments as today, by setting an interest rate level. However, some adjustments may have to be made to the definition of monetary aggregates and possibly also to the base and/or the ratios of reserve requirements. Even in the most extreme and unlikely scenario, where the central bank would issue CBDC the public would have access to and massively adopt, banks role in distributing credit would likely not be seriously impaired. Banks might rather have less direct information on their clients. They would possibly also become more dependent on central bank refinancing, which would call for a clear and pre-announced lending of last resort policy in order to limit moral hazard considerations.
Blockchain technology has the potential to disrupt how cryptography is done. In this work, we propose to view blockchains as an “enabler”, much like indistinguishability obfuscation [5, 23, 46] or one-way functions, for building a variety of cryptographic systems. Our contributions in this work are as follows:
1.
A Framework for Proof-of-Stake based Blockchains: We provide an abstract framework for formally analyzing and defining useful security properties for Proof-of-Stake (POS) based blockchain protocols. Interestingly, for some of our applications, POS based protocols are more suitable. We believe our framework and assumptions would be useful in building applications on top of POS based blockchain protocols even in the future.
2.
Blockchains as an Alternative to Trusted Setup Assumptions in Cryptography: A trusted setup, such as a common reference string (CRS) has been used to realize numerous systems in cryptography. The paragon example of a primitive requiring trusted setup is a non-interactive zero-knowledge (NIZK) system. We show that already existing blockchains systems including Bitcoin, Ethereum etc. can be used as a foundation (instead of a CRS) to realize NIZK systems. The novel aspect of our work is that it allows for utilizing an already existing (and widely trusted) setup rather than proposing a new one. Our construction does not require any additional functionality from the miners over the already existing ones, nor do we need to modify the underlying blockchain protocol. If an adversary can violate the security of our NIZK, it could potentially also take over billions of dollars worth of coins in the Bitcoin, Ethereum or any such cryptocurrency!
We believe that such a “trusted setup” represents significant progress over using CRS published by a central trusted party. Indeed, NIZKs could further serve as a foundation for a variety of other cryptographic applications such as round efficient secure computation [33, 36].
3.
One-time programs and pay-per use programs: Goldwasser et al. [29] introduced the notion of one time program and presented a construction using tamper-proof hardware. As noted by Goldwasser et al. [29], clearly a one-time program cannot be solely software based, as software can always be copied and run again. While there have been a number of follow up works [4, 6, 30], there are indeed no known constructions of one-time programs which do not rely on self destructing tamper-proof hardware (even if one uses trusted setup or random oracles). Somewhat surprisingly, we show that it is possible to base one-time programs on POS based blockchain systems without relying on trusted hardware. Our ideas do not seem to translate over to Proof-of-Work (POW) based blockchains.
We also introduce the notion of pay-per-use programs which is simply a contract between two parties — service provider and customer. A service provider supplies a program such that if the customer transfers a specific amount of coins to the provider, it can evaluate the program on any input of its choice once, even if the provider is offline. This is naturally useful in a subscription based model where your payment is based on your usage.
Blockchain is a decentralized transaction and data management technology developed first for Bitcoin cryptocurrency. The interest in Blockchain technology has been increasing since the idea was coined in 2008. The reason for the interest in Blockchain is its central attributes that provide security, anonymity and data integrity without any third party organization in control of the transactions, and therefore it creates interesting research areas, especially from the perspective of technical challenges and limitations. This paper highlights the architecture, benefits and applications of Blockchain Technology.
The concept of a Turing machine has been well defined. It would be sufficient to show that Bitcoin uses a dual stack architecture that acts as a dual counter machine. Such systems have already been demonstrated as being Turing complete. We demonstrate that Bitcoin script is a minimal family of which λ and R are members. Further using the compositional product rule and the iteration rule we demonstrate that Bitcoin scripting is Turing complete with the limitations imposed on any realworld computer. This limitation is that there cannot be an infinite tape. Iterations can be simulated using an “unrolled” loop function with allocation to the “Alt” stack. As the product rule states that if A, B are machines, then A.B is also a machine. The iteration rule shows that if A is a machine then (A) is also a machine. Further the minimum power of A under which the observed square of the final configuration is blank. The consequence of these rules is that for every partial recursive function of in variables we can show that it can be evaluated by machine of the proposed family.
Vinay Reddy Mallidi, V. Madhu Viswanatham, P. Ashok Kumar
For the past few years, the market has changed a lot and it has become dynamic and demanding which has put the market into a competitive environment. The supply chain plays a crucial role to adapt the business to the dynamic environment as it is very reliant on collaboration integration as well as flexibility. The applications related to the supply chain have gotten the attention of many business owners and to improve the flow control of the supply chain many specialized applications are implemented. One of the most important new technological applications in the supply chain is blockchain technology which has garnered the attention of many business owners as it can be quickly adapted to dynamic market conditions and in the business environment. One upon reading this will get to know about the effect of blockchain technology utilization on this field. The results of the research paper recommend that companies invest in blockchain technology so that the supply chain becomes more transparent, flexible, and secure. There is no doubt in the fact that blockchain technology plays an important role in developing trust with the stakeholder of the supply chain. In the end, the research paper has also given some considerations on the implications that are positive as well as the potential of the blockchain in the field of collaboration and integration.
The Internet of Things is a proliferating industry, which is transforming many homes and businesses, making them smart. However, the rapid growth of these devices and the interactions between these devices, introduces many challenges including that of a secure management system for the identities and interactions of the devices. While the centralized model has worked well for many years, there is a risk of the servers becoming bottlenecks and a single point of failure, thereby making them vulnerable to Denial-of-Service attacks. As a backbone of these interactions, Blockchain is capable of creating a highly secure, independent and distributed platform. Blockchain is a peer to peer, distributed ledger system that stores all the transactions taking place within the network. The main purpose of the servers that form a part of the distributed system is to provide a consensus, using various consensus algorithms, on the state of the blockchain at any given time and to store a copy of all the transactions taking place. This thesis explores the Blockchain technology in general and investigates its potential with regard to access management of constrained devices. A proof of concept system has been designed and implemented that demonstrates a simplified access management system using Ethereum Blockchain. This was done to check whether the concept can be applied at a global level. Although the latency of the network depends on the computing power of the resources participating in the Blockchain, an evaluation of the proof of concept system has been made, keeping in mind the smallest device that can be involved in the consensus process. Docker containers have been used to simulate a cluster of the nodes participating in the Blockchain, in order to examine the implemented system. An outline of the various advantages and the limitations of Blockchains in general, as well as the developed proof of concept system, has also been provided.
Bitcoins original idea proposed a trustless monetary system, without the need of \nintermediaries. In recent years, these very intermediaries it originally tried to circumvent, have \ngained an increased interest in Bitcoin’s underlying technology, the Blockchain. It presents a \ndecentralized database technology, suitable for exchanging value in an untrusted environment. \nConsequently, it introduces an innovation in both economics and information technology. \nIn this explorative study, we aim to investigate how Bitcoin and Blockchain technology may \nimpact the monetary and financial system. By conducting 20 in-depth interviews from a broad \nrange of stakeholders and a literature review in this new topic of interest, we have identified \ntwo main themes introduced with this new technology. First, we seek to understand how the \nfuture of money could unfold with Cryptocurrencies and Central Bank issued Digital Currency \n(CBDC). The former is recognized to have a series of specialized architectures, spanning from \nsimple monetary transactions to complex platforms enabling a decentralized economy to \nevolve. CBDC is not necessarily reliant on blockchain technology, but the of digitally issued \ncurrencies and blockchains introduces new fiscal and monetary policy toolkits. There are \nhowever a series of intricate questions that needs to be addressed before CBDC could act as a \ncomplement or replacement for physical currency. Lastly, we explore how the future of \nfinance will be affected by blockchain technology and the cryptoeconomy. Banks may be \nfacing increased competition from new entrants, where blockchain technology may facilitate \nreduced costs in terms of regulatory compliance, efficiency in transactions and settlement, and \nreconciliation. Moreover, new financial services are introduced by financial technology \ninnovation. This might change the business model of banks and other financial institutions \ndrastically. Furthermore, cryptocurrencies introduce new funding possibilities and enables \norganizations to evolve with no governing body. This might facilitate a new economic system, \ncalled the cryptoeconomy. \nDevelopment in blockchain technology is mentioned to be at the same maturity stage as the \nInternet by the early 1990s. There are several uncertainties regarding its future applications. \nHowever, smart contracts seems to be an interesting application, facilitating automation in a \nrange of applications.
Lin Chen, Lei Xu, Zhimin Gao, Nolan Shah · 6 authors
Transaction system build on top of blockchain, especially smart contract, is becoming an important part of world economy. However, there is a lack of formal study on the behavior of users in these systems, which leaves the correctness and security of such system without a solid foundation. Unlike mining, in which the reward for mining a block is fixed, different execution results of a smart contract may lead to significantly different payoffs of users, which gives more incentives for some user to follow a branch that contains a wrong result, even if the branch is shorter. It is thus important to understand the exact probability that a branch is being selected by the system. We formulate this problem as the (+-)-Biased Ballot Problem as follows: there are n voters one by one voting for either of the two candidates A and B. The probability of a user voting for A or B depends on whether the difference between the current votes of A and B is positive or negative. Our model takes into account the behavior of three different kinds of users when a branch occurs in the system -- users having preference over a certain branch based on the history of their transactions, and users being indifferent and simply follow the longest chain. We study two important probabilities that are closely related with a blockchain based system - the probability that A wins at last, and the probability that A receives d votes first. We show how to recursively calculate the two probabilities for any fixed n and d, and also discuss their asymptotic values when n and d are sufficiently large.