MixEth: Efficient, Trustless Coin Mixing Service for Ethereum

Coin mixing is a prevalent privacy-enhancing technology for cryptocurrency users. In this paper, we present MixEth, which is a trustless coin mixing service for Turing-complete blockchains. MixEth does not rely on a trusted setup and is more efficient than any proposed trustless coin tumbler. It requires only 3 on-chain transactions at most per user and 1 off-chain message. It achieves strong notions of anonymity and is able to resist denial-of-service attacks. Furthermore the underlying protocol can also be used to efficiently shuffle ballots, ciphertexts in a trustless and decentralized manner

Understanding (Mis)Behavior on the EOSIO Blockchain

© 2020 Copyright is held by the owner/author(s). EOSIO has become one of the most popular blockchain platforms since its mainnet launch in June 2018. In contrast to the traditional PoW-based systems (e.g., Bitcoin and Ethereum), which are limited by low throughput, EOSIO is the first high throughput Delegated Proof of Stake system that has been widely adopted by many decentralized applications. Although EOSIO has millions of accounts and billions of transactions, little is known about its ecosystem, especially related to security and fraud. In this paper, we perform a large-scale measurement study of the EOSIO blockchain and its associated DApps. We gather a large-scale dataset of EOSIO and characterize activities including money transfers, account creation and contract invocation. Using our insights, we then develop techniques to automatically detect bots and fraudulent activity. We discover thousands of bot accounts (over 30% of the accounts in the platform) and a number of real-world attacks (301 attack accounts). By the time of our study, 80 attack accounts we identified have been confirmed by DApp teams, causing 828,824 EOS tokens losses (roughly $2.6 million) in total

MixEth: efficient, trustless coin mixing service for Ethereum

Coin mixing is a prevalent privacy-enhancing technology for cryptocurrency users. In this paper, we present MixEth, which is a trustless coin mixing service for Turing-complete blockchains. MixEth does not rely on a trusted setup and is more efficient than any proposed trustless coin tumbler. It requires only 3 on-chain transactions at most per user and 1 off-chain message. It achieves strong notions of anonymity and is able to resist denial-of-service attacks. Furthermore the underlying protocol can also be used to efficiently shuffle ballots, ciphertexts in a trustless and decentralized manner

Detailed analysis of Ethereum network on transaction behavior, community structure and link prediction

Ethereum, the second-largest cryptocurrency after Bitcoin, has attracted wide attention in the last few years and accumulated significant transaction records. However, the underlying Ethereum network structure is still relatively unexplored. Also, very few attempts have been made to perform link predictability on the Ethereum transactions network. This paper presents a Detailed Analysis of the Ethereum Network on Transaction Behavior, Community Structure, and Link Prediction (DANET) framework to investigate various valuable aspects of the Ethereum network. Specifically, we explore the change in wealth distribution and accumulation on Ethereum Featured Transactional Network (EFTN) and further study its community structure. We further hunt for a suitable link predictability model on EFTN by employing state-of-the-art Variational Graph Auto-Encoders. The link prediction experimental results demonstrate the superiority of outstanding prediction accuracy on Ethereum networks. Moreover, the statistic usages of the Ethereum network are visualized and summarized through the experiments allowing us to formulate conjectures on the current use of this technology and future development. Subjects Data Mining and Machine Learning, Data Science, Emerging Technologie

Design Patterns for Ethereum Smart Contracts

The invention of Bitcoin in 2008 offered a solution for a digital currency that could be used without a trusted third-party settling disputes over transactions. Bitcoin relied on a technology known as the blockchain, which can be described as a distributed database that relies on a consensus mechanism (generally Proof Of Work is employed) to be resilient against tampering. Ethereum, launched in 2015, leveraged the blockchain technology to augment the initial proposal of Bitcoin, enabling computational statements to be executed as part of each block validation. The platform offers a Turing-complete runtime environment (the Ethereum Virtual Machine), which can run smart contracts - scripts that verify and enforce the execution of predefined legal contracts. The technical development of smart contracts present significant challenges that are not well modeled by the current body of knowledge and practices of software engineering. In fact, some of the characteristic of blockchain make the contract execution uncontrollable by the programmer and immutable after deployment. Also, the potential security risks are considerable, since there is a large incentive to exploit vulnerabilities in a smart contract for financial gain. Considering the concerns presented above, the establishment of well understood and welldefined design patterns for the development of smart contracts is of paramount importance. In the realm of software engineering, design patterns are defined as generic and reusable solutions to common problems in software design. In the context of this work, a survey of design patterns that target the Ethereum framework was performed, with an extensive analysis regarding the context in which they can be employed, as well as implementations, examples and consequences of their use. A total of 11 design patterns were analysed. The design patterns identified for the Ethereum framework focus on several concerns specific to this platform – most of these concerns revolve around safety, upgradeability, and the limitations inherent to the sandboxed approach of the Ethereum Virtual Machine. A Decentralized Application (dApp) was created to showcase the employment of several of the identified contracts, and to highlight the value they can provide. This dApp offers a framework for decentralized betting in a trustless environment, where neither the user needs to trust the owner nor vice-versa. The dApp implements several use cases that are reliant on the identified design patterns.A invenção da Bitcoin em 2018 disponibilizou uma solução para uma moeda digital que poderia ser usada sem a necessidade de envolver terceiros para a mediação de transações. A Bitcoin recorre a uma tecnologia conhecida como blockchain, que consiste numa base de dados distribuída, assente num mecanismo de consenso resistente a alterações não acordadas. Ethereum, lançada em 2015, utiliza a mesma tecnologia da blockchain para oferecer uma plataforma que se baseia na Bitcoin, mas que também permite a execução de instruções como parte do processo de validação de cada bloco. A plataforma permite correr contratos inteligentes (smart contracts) - scripts que verificam e garantem a correta execução de um contrato predefinido. O desenvolvimento técnico de contratos inteligentes apresenta desafios significativos que não são atualmente modelados pela área de engenharia de software. De facto, algumas das caraterísticas da blockchain fazem com que a execução de contratos não seja controlável pelo programador e também com que estes contratos sejam imutáveis após serem colocados na rede principal de Ethereum. Tendo em conta os pontos anteriores, é importante o estabelecimento de padrões de desenho (design patterns) bem definidos para serem usados em contratos inteligentes. No contexto deste trabalho, foi realizada uma análise dos padrões de desenho usados em Ethereum, tendo em conta o contexto em que são utilizados, as suas implementações e exemplos da sua utilização em contratos existentes. Um total de 11 padrões de desenho foram identificados e analisados. Uma Decentralized Application (dApp) foi desenvolvida para demonstrar o emprego dos padrões de desenho identificados. Esta dApp disponibiliza uma framework para se efetuar apostas de uma forma descentralizada, em que nem o utilizador necessita de confiar no dono do contrato, nem vice-versa

Decentralised Finance's Unregulated Governance: Minority Rule in the Digital Wild West

Decentralised finance (DeFi) is a category of unlicensed, unregulated, and non-custodial financial services that utilise public, distributed ledgers like Ethereum. The Bloomberg Galaxy DeFi Index, launched in August 2021, includes nine Ethereum-based projects – non-custodial exchanges as well as lending and derivatives platforms. Each project is governed, at least in part, by a community of unregistered individuals that hold tradable voting rights tokens (also known as governance tokens). Voting rights tokens allow holders to vote on proposed changes to a DeFi project’s features, parameters, or rules. DeFi’s governance power is thus linked to the distribution and exercise of tokenised voting rights. Since DeFi projects are typically not managed by companies or public institutions, not much is known about DeFi’s governance. Regulators and law-makers from the United States recently asked if DeFi’s governance entails a new class of “shadowy” elites. In response, we conducted an exploratory, multiple-case study that focuses on the voting rights tokens issued by the nine projects from Bloomberg’s Galaxy DeFi index. Our mixed methods approach draws on Ethereum-based data about the distribution, trading, and staking of voting rights tokens, as well as project documentation and archival records. Our findings contribute knowledge about the entitlements of DeFi’s voting rights tokens, the initial distribution strategies, and the actual voting and delegation activity. Our principal finding is that DeFi’s voting rights are highly concentrated, and the exercise of these rights is very low. Our theoretical contribution is descriptive: minority rule is the probable consequence of tradable voting rights plus the lack of applicable anti-concentration or anti-monopoly laws. We interpret DeFi’s minority rule as timocratic and acknowledge its possible transition to oligarchy