In blockchain networks, topology discovery is a prerequisite when investigating the network characteristics (e.g., performance and robustness), which can provide a deeper comprehension of the behavior of the nodes and topology dynamicity. In this paper, we conduct a longitudinal study on the Bitcoin topology by collecting network snapshots from 2018 to 2022 with Node-Probe, our topology discovery technique that uses recursive scanning to find all reachable nodes in the Bitcoin network. Using Node-Probe, we have collected 5-week-long snapshots (36-day-long snapshots) of the Bitcoin main network and analyzed the network properties, community structure, and topology dynamicity. We confirm that our approach achieves a precision of 99% with a recall of 98% in inferring the topology. Analytical results on community structure show that the Bitcoin network has $\times 4$ more communities than what should be expected from a random network. Meanwhile, analytical results on dynamicity indicate that the topology stands firmly on heavy and long-running nodes. Improving the propagation mechanism using master nodes could improve the propagation delay by proximity $\times 25$ compared with the Bitcoin default protocol. Considering a K-anonymity attack, any transaction from one of the autonomous systems containing only a single Bitcoin node can easily be linked to real users' IP information.

中文翻译：

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使用 Node-Probe 表征比特币网络拓扑

在区块链网络中，拓扑发现是研究网络特征（例如性能和鲁棒性）的先决条件，它可以提供对节点行为和拓扑动态性的更深入理解。在本文中，我们通过使用 Node-Probe 收集 2018 年至 2022 年的网络快照来对比特币拓扑进行纵向研究，Node-Probe 是我们的拓扑发现技术，使用递归扫描来查找比特币网络中所有可到达的节点。使用Node-Probe，我们收集了比特币主网5周的快照（36天的快照），并分析了网络属性、社区结构和拓扑动态。我们确认我们的方法在推断拓扑时达到了 99% 的精度和 98% 的召回率。社区结构分析结果表明，比特币网络具有$\times 4$比随机网络预期的社区数量更多。同时，动态性分析结果表明该拓扑在重且长时间运行的节点上站稳了脚跟。使用主节点改进传播机制可以通过接近来改善传播延迟$\times 25$与比特币默认协议相比。考虑到 K-匿名攻击，来自仅包含单个比特币节点的自治系统之一的任何交易都可以轻松链接到真实用户的 IP 信息。