Anonymity in Bitcoin? – The Users’ Perspective

This article analyzes how users perceive the degree of anonymity provided by the Bitcoin network, to what extent they are concerned about anonymity when using Bitcoin, whether they are knowledgeable of and concerned about specific de-anonymization attacks, and if they are aware of and adopt privacy-preserving countermeasures. A user survey with 125 active Bitcoin users reveals that 70% associate a medium or high level of anonymity with the Bitcoin network and rate their concerns as either low or medium. But almost every 5th user has already considered abandoning Bitcoin because of being concerned about anonymity. Though one third are aware of the risk of de-anonymizing the Blockchain but are not concerned, another almost 50% indeed feel concerned. Our findings have implications for users and developers, suggesting that actions should be undertaken to increase privacy awareness and the level of anonymity provided by the Blockchain and the Bitcoin network

Anonymization Technologies of Cryptocurrency Transactions as Money Laundering Instrument

This article is devoted to the exploration of services of anonymizing transactions, based on the Mixer, CoinJoin and CoinSuffle technologies, as well as to the description of the core principles of operation of these technologies and technical details. It analyzes the advantages and disadvantages of different realizations of this service. It formulates the problem of cryptocurrency laundering through anonymization services and offers solutions to this problem.Keywords: cryptocurrency, blockchain, bitcoin, mixing service, mining, money laundering

A Prevention and a Traction System for Ransomware Attacks

Over the past three years, especially following WannaCry malware, ransomware has become one of the biggest concerns for private businesses, state, and local government agencies. According to Homeland Security statistics, 1.5 million ransomware attacks have occurred per year since 2016. Cybercriminals often use creative methods to inject their malware into the target machines and use sophisticated cryptographic techniques to hold hostage victims' files and programs unless a certain amount of equivalent Bitcoin is paid. The return to the cybercriminals is so high (estimated \$1 billion in 2019) without any cost because of the advanced anonymity provided by cryptocurrencies, especially Bitcoin \cite{Paquet-Clouston2019}. Given this context, this study first discusses the current state of ransomware, detection, and prevention systems. Second, we propose a global ransomware center to better manage our concerted efforts against cybercriminals. The policy implications of the proposed study are discussed in the conclusion section

Peer-to-Peer EnergyTrade: A Distributed Private Energy Trading Platform

Blockchain is increasingly being used as a distributed, anonymous, trustless framework for energy trading in smart grids. However, most of the existing solutions suffer from reliance on Trusted Third Parties (TTP), lack of privacy, and traffic and processing overheads. In our previous work, we have proposed a Secure Private Blockchain-based framework (SPB) for energy trading to address the aforementioned challenges. In this paper, we present a proof-on-concept implementation of SPB on the Ethereum private network to demonstrates SPB's applicability for energy trading. We benchmark SPB's performance against the relevant state-of-the-art. The implementation results demonstrate that SPB incurs lower overheads and monetary cost for end users to trade energy compared to existing solutions

BlockTag: Design and applications of a tagging system for blockchain analysis

Annotating blockchains with auxiliary data is useful for many applications. For example, e-crime investigations of illegal Tor hidden services, such as Silk Road, often involve linking Bitcoin addresses, from which money is sent or received, to user accounts and related online activities. We present BlockTag, an open-source tagging system for blockchains that facilitates such tasks. We describe BlockTag's design and present three analyses that illustrate its capabilities in the context of privacy research and law enforcement

Anonymity in Bitcoin and Bitmessage

This report describes two projects created by the author which are based on ideas which originate from the Bitcoin community. The first, bmd, is a re-implementation of the Bitmessage protocol in go. Bitmessage is an anonymous and secure messaging system invented by Jonathan Warren, who was inspired by the design of Bitcoin's p2p network. [WARR1] The second is Shufflepuff, an implementation of a protocol called CoinShuffle[RUFF1] which allows several people to construct a Bitcoin transaction with an input and an output for each participant without any participant knowing who owns which output. CoinShuffle was invented by Tim Ruffing et al, and it is an upgrade of a protocol called CoinJoin, invented by Gregory Maxwell. This paper discusses the background, properties, applications, and design of bmd and Shufflepuff. There is also a report of a performance analysis on bmd.Electrical and Computer Engineerin