TxProbe: Discovering Bitcoin's Network Topology Using Orphan Transactions
This addresses the challenge of network measurement for Bitcoin, enabling characterization of performance, fairness, and robustness, though it is incremental as it builds on existing knowledge of orphan transactions.
The paper tackles the problem of observing Bitcoin's hidden peer-to-peer network topology by introducing TxProbe, a technique that leverages orphan transactions to reconstruct it, achieving over 90% precision and recall in experiments on Bitcoin testnet.
Bitcoin relies on a peer-to-peer overlay network to broadcast transactions and blocks. From the viewpoint of network measurement, we would like to observe this topology so we can characterize its performance, fairness and robustness. However, this is difficult because Bitcoin is deliberately designed to hide its topology from onlookers. Knowledge of the topology is not in itself a vulnerability, although it could conceivably help an attacker performing targeted eclipse attacks or to deanonymize transaction senders. In this paper we present TxProbe, a novel technique for reconstructing the Bitcoin network topology. TxProbe makes use of peculiarities in how Bitcoin processes out of order, or "orphaned" transactions. We conducted experiments on Bitcoin testnet that suggest our technique reconstructs topology with precision and recall surpassing 90%. We also used TxProbe to take a snapshot of the Bitcoin testnet in just a few hours. TxProbe may be useful for future measurement campaigns of Bitcoin or other cryptocurrency networks.