An Exploration of Bitcoin Mining Practices:Miners’ Trust Challenges and Motivations

Bitcoin blockchain technology is a distributed ledger of nodes authorizing transactions between anonymous parties. Its key actors are miners using computational power to solve mathematical problems for validating transactions. By sharing blockchain's characteristics, mining is a decentralized, transparent and unregulated practice, less explored in HCI, so we know little about miners' motivations and experiences, and how these may impact on different dimensions of trust. This paper reports on interviews with 20 bitcoin miners about their practices and trust challenges. Findings contribute to HCI theories by extending the exploration of blockchain's characteristics relevant to trust with the competitiveness dimension underpinning the social organization of mining. We discuss the risks of collaborative mining due to centralization and dishonest administrators, and conclude with design implications highlighting the need for tools monitoring the distribution of rewards in collaborative mining, tools tracking data centers' authorization and reputation, and tools supporting the development of decentralized pools

Poster: Deterring Ddos Attacks On Blockchain-Based Cryptocurrencies Through Mempool Optimization

In this paper, we highlight a new form of distributed denial of service (DDoS) attack that impacts the memory pools of cryptocur-rency systems causing massive transaction backlog and higher mining fees. Towards that, we study such an attack on Bitcoin mempools and explore its effects on the mempool size and transaction fees paid by the legitimate users. We also propose countermeasures to contain such an attack. Our countermeasures include fee-based and age-based designs, which optimize the mempool size and help to counter the effects of DDoS attacks. We evaluate our designs using simulations in diverse attack conditions

Smart contracts - blockchains in the wings

In recent years, electronic contracts have gained attention, especially in the context of the blockchain technology. While public blockchains are considered secure, legally binding under certain circumstances, and without any centralized control, they are applicable to a wide range of application domains, such as public registries, registry of deeds, or virtual organizations. As one of the most prominent blockchain examples, the Bitcoin system has reached large public, financial industry‐related, and research interest. Another prominent block‐chain example, Ethereum, which is considered a general approach for smart contracts, has taken off too. Nevertheless, various different set of functions, applications, and stakeholders are involved in this smart contract arena. These are highlighted and put into interrelated technical, economic, and legal perspectives