Dark web marketplaces have been a significant outlet for illicit trade, serving millions of users worldwide for over a decade. However, not all users are the same. This paper aims to identify the key players in Bitcoin transaction networks linked to dark markets and assess their role by analysing a dataset of 40 million Bitcoin transactions involving 31 markets in the period 2011-2021. First, we propose an algorithm that categorizes users either as buyers or sellers and shows that a large fraction of the traded volume is concentrated in a small group of elite market participants. Then, we investigate both market star-graphs and user-to-user networks and highlight the importance of a new class of users, namely `multihomers' who operate on multiple marketplaces concurrently. Specifically, we show how the networks of multihomers and seller-to-seller interactions can shed light on the resilience of the dark market ecosystem against external shocks. Our findings suggest that understanding the behavior of key players in dark web marketplaces is critical to effectively disrupting illegal activities.

翻译：暗网市场一直是非法交易的重要渠道，十多年来为全球数百万用户提供服务。然而，并非所有用户都扮演相同角色。本文旨在识别与暗网市场相关的比特币交易网络中的关键参与者，并通过分析2011-2021年间涉及31个市场的4000万条比特币交易数据集，评估其作用。首先，我们提出一种将用户分类为买方或卖方的算法，并揭示大部分交易量集中于少数精英市场参与者。其次，我们同时研究了市场星型图与用户间网络，重点阐明一类新型用户——即同时在多个市场运营的"多栖用户"的重要性。具体而言，我们展示了多栖用户网络及卖家间交互网络如何揭示暗市生态系统抵御外部冲击的韧性。研究结果表明，理解暗网市场中关键参与者的行为对于有效打击非法活动至关重要。