Bitcoin Under Stress: Measuring Infrastructure Resilience 2014-2025

TL;DR

This study assesses Bitcoin's resilience to submarine cable failures over 11 years, revealing that while the network is robust against random failures, targeted attacks are more effective, and TOR adoption generally enhances resilience.

Contribution

It introduces a multiplex percolation framework including a 4-layer TOR relay model and provides the first empirical measurement of Bitcoin's physical-layer resilience over a decade.

Findings

Bitcoin's critical failure threshold for random failures is approximately 0.72--0.92.

Targeted attacks are significantly more effective, with thresholds of 0.05--0.20.

TOR adoption increases network resilience under current relay distribution.

Abstract

Bitcoin's design promises resilience through decentralization, yet the physical infrastructure supporting the network creates hidden dependencies. We present the first longitudinal study of Bitcoin's resilience to submarine cable failures, using 11 years of P2P network data (2014--2025) and 68 verified cable fault events. Applying a Buldyrev-style cascade model at country level, we find that Bitcoin's clearnet (non-TOR) critical failure threshold $p_c \approx 0.72$--$0.92$ for random failures, meaning the vast majority of inter-country cables must fail before significant node disconnection. Targeted attacks are an order of magnitude more effective ($p_c = 0.05$--$0.20$). To address the majority of nodes now using TOR with unobservable locations, we develop a 4-layer multiplex model incorporating TOR relay infrastructure. Because relay bandwidth concentrates in well-connected European countries, TOR adoption increases resilience under current relay geography ($\Delta p_c \approx +0.02$--$+0.10$) rather than introducing hidden fragility. Empirical validation confirms weak physical-layer coupling: 87% of historical cable faults caused less than 5% node impact. We contribute: (1) a multiplex percolation framework for overlay-underlay coupling, including a 4-layer TOR relay model; (2) the first empirical measurement of Bitcoin's physical-layer resilience over a decade; and (3) evidence that TOR adoption amplifies resilience, with distributional bounds quantifying uncertainty under partial observability.