Submarine Cable Cut-offs Aren't the Real Risk for Bitcoin: Discover Where the True Weak Points Are

A comprehensive study by the University of Cambridge reveals a surprising finding: despite growing geopolitical concerns over the security of submarine cable entries, these disconnections have an almost negligible impact on the Bitcoin network. However, researchers identified a much more concrete vulnerability: the concentration of nodes in just five cloud providers. This discovery completely redefines our understanding of where the true infrastructure risks to the network lie.

Using 11 years of network data, 68 verified submarine cable failure events, and 8 million node observations, researchers Wenbin Wu and Alexander Neumueller built a quantitative model that challenges conventional theories about Bitcoin’s fragility in the face of physical disruptions.

The Cable Entry Myth: Why Submarine Cuts Are Geological Noise

In March 2024, a submarine earthquake off the coast of Ivory Coast severed seven submarine cables simultaneously, severely disrupting regional internet connectivity with an interference score over 11,000. For Bitcoin, the impact was virtually nil.

Only five nodes were affected, representing 0.03% of the global network, with a disruption of just -2.5% in operation. No price volatility. No consensus interruptions. Not even temporary fragmentation records.

Historical analysis of cable entries during failure events revealed a consistent pattern: 87% of the 68 verified submarine cable events caused changes in nodes of less than 5%. The average impact was -1.5%, with a median of just -0.4%. The correlation between these disconnections and price disruptions was practically zero (r = -0.02).

The researchers modeled Bitcoin as a three-layer architecture: first, a physical connectivity layer linking 225 countries via 354 submarine cable links; second, an autonomous system (ASN) layer routing traffic; and third, an overlay peer-to-peer Bitcoin network.

The revealing point: randomly removing between 72% and 92% of all international cable entries would be necessary to disconnect more than 10% of visible Bitcoin nodes. This means that cable entries, while vulnerable to geopolitical interference, possess inherent redundancy that protects the network from catastrophic disruptions.

Where We Truly Live on the Edge: Cloud Service Concentration

If submarine cables are a low-impact risk, where is the real weakness? Data points directly to five cloud providers.

A coordinated attack on the main autonomous systems, based on node density, would require eliminating only 5% of routing capacity to cause over 10% disconnections in accessible public network nodes. This scenario doesn’t require dramatic submarine operations, just access restrictions, cloud service outages, or coordinated regulatory actions.

The main networks identified are:

• Hetzner: hosts 869 nodes (3.75% of total)
• Comcast: 348 nodes (1.5%)
• OVHcloud: 348 nodes (1.5%)
• Amazon Web Services: 336 nodes (1.45%)
• Google Cloud: 313 nodes (1.35%)

Together, these five providers host a level of concentration that, if coordinated shutdowns occurred, could cause propagation delays and temporary consensus issues, though not a complete collapse. Recent cloud service outages—such as Amazon’s software deployment failure in March 2026 or infrastructure attacks in AWS’s Middle East region—demonstrate these risks are real, not just theoretical.

However, this threat has a crucial twist: Tor provides an unexpected line of defense.

Tor: From Privacy Tool to Structural Resilience Layer

The composition of the Bitcoin network underwent a radical transformation directly correlated with censorship and regulatory repression events. Adoption of Tor grew exponentially:

• 2014: virtually zero Tor nodes
• 2021: 2,478 Tor nodes (23% of the network)
• 2022: 7,617 Tor nodes (52%)
• March 2026: 14,602 Tor nodes (63% of the 23,150 accessible nodes)

This growth synchronized with specific geopolitical events:

• Internet blackout in Iran (2019)
• Coup in Myanmar (2021)
• Mining ban in China (2021)

Node operators decentralized toward anti-censorship infrastructure organically, without centralized coordination. Bitcoin’s network demonstrated an adaptive self-organization capacity that enhances resilience even under external pressures.

Here’s the fascinating part: although Tor nodes cannot be geographically identified by conventional surveillance systems, Tor relays do have known physical locations. Cambridge researchers modeled a four-layer scenario where failures in cable entries could potentially disconnect multiple Tor relays simultaneously.

Results were counterintuitive: the four-layer model always produced higher critical failure thresholds than the public network-only model, with increases between 0.02 and 0.10. The concentration of Tor relay consensus weight in Germany, France, and the Netherlands—countries with extensive redundant cable connectivity—means an attacker would need to take down significantly more infrastructure to impact both public routes and Tor circuits simultaneously.

The Chinese Factor and the Bounce Toward Decentralization

Bitcoin’s resilience hit its minimum point of 0.72 in 2021, coinciding with maximum hash power concentration in East Asia (74% in 2019). The geographic centralization of nodes eroded network resilience by 22% between 2018 and 2021.

What happened next was dramatic. After China’s mining ban in 2021, infrastructure decentralization caused the resilience threshold to jump to 0.88—a rebound of 0.16 points. Simultaneously, Tor adoption accelerated.

While researchers avoid attributing a single causal link, data strongly suggests that regulatory pressure inadvertently prompted a geographic reallocation of mining that strengthened the network. Repression, paradoxically, catalyzes decentralized adaptation.

A crucial technical detail: part of the apparent centralization observed in public databases results from measurement artifacts. As Tor adoption grows, the visible sample of public nodes concentrates geographically in fewer locations, raising the Herfindahl-Hirschman concentration index from 166 to 4,163. However, Hetzner’s actual share decreased from 10% to 3.6%. Numbers highlight the optical illusion Tor creates in conventional centralization metrics.

Beyond Submarine Scenarios: Assessing the Real Threat

Concerns about cable entry security will continue to escalate. Baltic Sea investigations, European Commission analyses, and alerts on Russian infrastructure reflect legitimate geopolitical anxiety. For Bitcoin, however, historical data clearly shows most cable cut events are noise.

The real battleground is autonomous system infrastructure and cloud services. A coordinated attack scenario targeting main ASes would require only 5% of routing capacity to cause significant disruptions in public network nodes—not a consensus collapse, but temporary connectivity degradation.

Unassessed protocol mechanisms—block relay networks, compact block relay, and Blockstream Satellite—add additional redundancy layers, making these estimates even more conservative. Bitcoin is not as fragile as critics imagine, but it is not completely decoupled from the underlying physical infrastructure either.

Conclusion: The Network Shows Elegant Degradation Under Pressure

Bitcoin operates under an evolving threat model. Submarine cable entries, despite geopolitical pressures, remain low-impact risks thanks to inherent redundancy and increasing Tor adoption. The true critical points lie in node concentrations within five cloud providers—scenarios where coordinated shutdowns or regulations could cause temporary disruptions without requiring dramatic submarine operations.

Paradoxically, regulatory pressure has driven decentralization. Each ban prompts migration toward anti-censorship infrastructure. Each censorship event strengthens Tor adoption. Bitcoin’s network is not a fragile system but an adaptive organism whose resilience increases under pressure. The real infrastructure risks deserve regulatory attention and technical monitoring— but in places far removed from where traditional geopolitical anxiety has historically focused.