Researchers Warn 95% of Bitcoin Nodes Could Be Vulnerable to Underwater Cable Attack

A new study from the Cambridge Centre for Alternative Finance reveals that a targeted attack on key underwater cables and routing providers could theoretically cripple the vast majority of Bitcoin’s public nodes.

In a new paper, researchers Wenbin Wu and Alexander Neumueller present the first longitudinal study of Bitcoin’s physical-layer resilience.

Decentralization is, of course, Bitcoin’s main selling point, but its logical software network is tethered to the physical internet infrastructure. The researchers used a cascade model to simulate what happens to Bitcoin nodes when inter-country submarine cables are severed.

The good news for the network is that random cable failures are mostly harmless. Between 72% and 92% of all inter-country submarine cables would need to be destroyed before the network experienced significant fragmentation (more than 10% of nodes disconnecting).

However, targeted and coordinated attacks substantially increase the threat profile. If an attacker specifically targeted “high-betweenness” cables, the failure threshold drops from 72% down to just 20%. The researchers identified 11 extremely critical Europe-North America cables.

Moreover, a targeted takedown of the top five Autonomous System Networks (ASNs) hosting Bitcoin nodes (Hetzner, OVH, Comcast, Amazon and Google Cloud) could demolish 95% of the network’s clearnet routing capacity.

TOR paradox

The network has adapted to global pressures via the massive adoption of the TOR network.

In 2014, only a few dozen Bitcoin nodes ran on TOR. By 2025, that number had surged to 64% of the entire network.

Historically, critics have argued that routing Bitcoin through TOR introduces a “hidden fragility,” as the physical locations of the nodes become unobservable.

Counterintuitively, the study proves that TOR actually strengthens Bitcoin’s physical resilience.

The data shows that TOR relay bandwidth is intensely concentrated in highly infrastructure-rich European countries like Germany, France and the Netherlands.

These nations have massive redundancies in both submarine cables and terrestrial fiber borders. They are insanely difficult to disconnect from the global internet. Routing Bitcoin through TOR creates a “compound barrier to disruption,” shielding nodes in peripheral, poorly connected nations by piggybacking on Europe’s robust physical infrastructure.