Bitcoin is one of the most prominent examples of a distributed cryptographic protocol that is extensively used in reality. Nonetheless, existing security proofs are property-based, and as such they do not support composition. In this work we put forth a universally composable treatment of the Bitcoin protocol. We specify the goal that Bitcoin aims to achieve as a ledger functionality in the (G)...

Background: Bitcoin, the most innovate digital currency as of now, created since 2008, even through experienced its ups and downs, still keeps drawing attentions to all parts of society. It relies on peer-to-peer network, achieved decentralization, anonymous and transparent. As the most representative digital currency, people curious to study how Bitcoin’ price changes in the past. Methods: In ...

We present the first large-scale survey to investigate how users experience the Bitcoin ecosystem in terms of security, privacy and anonymity. We surveyed 990 Bitcoin users to determine Bitcoin management strategies and identified how users deploy security measures to protect their keys and bitcoins. We found that about 46% of our participants use web-hosted solutions to manage at least some of...

Six assertions concerning the status of Bitcoin are formulated and defended: (i) Bitcoin is not and will not become a currency-like informational commodity, (ii) currencylike informational commodities that aren’t currencies must be frauds, (ii) specific BTC amounts may become monetized and thus may be turned into financial assets, (iii) currently no BTC amounts are monetized in any currency are...

Interest in digital currencies, especially Bitcoin, has exploded over the past year. The cryptocurrency Bitcoin was created in 2009 by an anonymous entity operating under the pseudonym Satoshi Nakamoto. Using cryptographic primitives to create a digital currency is not particularly new – David Chaum proposed electronic cash nearly thirty years ago. What is different about Bitcoin is its success...

Bitcoin is gaining increasing adoption and popularity nowadays. In spite of its reliance on pseudonyms, Bitcoin raises a number of privacy concerns due to the fact that all of the transactions that take place in the system are publicly announced. The literature contains a number of proposals that aim at evaluating and enhancing user privacy in Bitcoin. To the best of our knowledge, ZeroCoin (ZC...

The Bitcoin cryptocurrency relies heavily on a variety of cryptographic functions and operations, which are currently assumed to be secure, but will inevitably be broken in the future. As Bitcoin tries to compete against traditional currencies, it remains to be seen how the Bitcoin protocol will need to change in response to weakened cryptography. To this end, this study systematically evaluate...

In this paper we discuss Bitcoin, the leader among the existing cryptocurrencies, to analyse its trends, success factors, current challenges and probable solutions to make it even better. In the introduction section, we discuss the history and working mechanism of Bitcoin. In the background section, we develop the ideas that evolved in the process of making a stable cryptocurrency. We also anal...

We present an in-depth analysis of Bitcoin mining algorithm across different hardware. We analyzed four mining algorithms from cgminer for CPUs and explored how number of cores, clock frequency, and various cache parameters affect the performance. Furthermore, we look into Intel’s hardware SHA-256 support in upcoming Skylake architecture and predict speedups gained there. We found that massivel...

On February 2014, $650.000.000 worth of Bitcoins disappeared. Currently it is unclear whether hackers or MtGox, the largest Bitcoin exchange, are to be blamed. In either case, the anonymous and unregulated nature of the Bitcoin system makes it practically impossible for innocent victims to get their money back. We have investigated the technical possibilities, solutions and implications of intr...