Research from the Cambridge Centre for Alternative Finance examines the Bitcoin network’s resilience to submarine Internet cable disruptions.
A study from the Cambridge Centre for Alternative Finance has quantified for the first time the critical failure threshold of submarine cables required to significantly impact the Bitcoin network. The research, first published in February and revised on March 12, was conducted by researchers Wenbin Wu and Alexander Neumueller, who used P2P network data from 2014 to 2025 and 68 verified cable failure events to build a nation-scale cascade model.
Submarine fiber optic cables carry approximately 99% of international Internet traffic. According to the study, the critical failure threshold for random cable removal sits between 0.72 and 0.92 – meaning that between 72% and 92% of all intercontinental submarine cables would need to fail simultaneously before more than 10% of network nodes disconnect. The study describes itself as the first longitudinal work on Bitcoin’s resilience to submarine cable failures.
However, the network proves more vulnerable to targeted attacks on strategic nodes within the cable network. Researchers describe this vector as “an order of magnitude more effective” than random failures, with a critical threshold ranging between 0.05 and 0.20. An attacker selectively targeting the main submarine cable chokepoints could therefore cause substantial damage with far fewer failures.
The study also examines the role of Tor (The Onion Router) in network resilience. According to the researchers, Tor “creates a composite barrier to disruption,” owing to the concentration of relay infrastructure in well-connected European countries such as Germany, France, and the Netherlands – nations equipped with extensive and redundant submarine connectivity. In fact, 64% of Bitcoin nodes are effectively “invisible” to researchers due to Tor adoption, which conceals their physical location. The study states that “Tor adoption enhances resilience within the current relay geography, rather than introducing hidden fragilities.”
