72% of subsea cables need to fail to impact Bitcoin, study shows

The past 11 years have shown that Bitcoin has been resilient to random intercontinental subsea internet cable failures, but could be susceptible to targeted attacks.

Nearly three-quarters of all undersea fibre optic internet cables (which carry about 99% of international internet traffic) would need to fail to have a significant impact on Bitcoin, according to a study released earlier this year.

In research first published in February and last revised on March 12, researchers Wenbin Wu and Alexander Neumueller from the Cambridge Centre for Alternative Finance said they used P2P network data from 2014 to 2025 and 68 verified cable fault events to apply a country-level cascade model to determine Bitcoin’s physical infrastructure resilience.

They claim it to be the first longitudinal study of Bitcoin’s resilience to submarine cable failures, and it helps to answer a long-standing question about what would happen to Bitcoin if the internet were to be disrupted. 

The researchers found that the critical failure threshold for random cable removal sits at 0.72 to 0.92, meaning 72% to 92% of all “inter-country” submarine cables would need to fail before more than 10% of network nodes disconnect. 

However, the Bitcoin network was more vulnerable to targeted attacks on certain subsea cable chokepoints, with researchers calling it an “order of magnitude more effective,” with a critical failure threshold of 0.05 to 0.20.

The study also found that Tor (The Onion Router) “creates a compound barrier to disruption,” given the current concentration of relay infrastructure in well-connected European countries.

Tor is similar to VPNs (virtual private networks), bouncing web traffic through a chain of volunteer-run servers around the world, wrapping each hop in a layer of encryption for privacy, like the layers of an onion.

Related: Is Tor still safe after Germany’s ‘timing attack?’ Answer: It’s complicated...

The Bitcoin network uses Tor to obfuscate nodes, meaning their physical locations are hidden. The paper revealed that 64% of Bitcoin nodes are essentially “invisible” to researchers.

“Tor adoption increases resilience under current relay geography rather than introducing hidden fragility,” it stated. 

This is because Tor relay infrastructure is concentrated in Germany, France, and the Netherlands — countries with extensive and redundant submarine cable connectivity — so cable failures rarely take down relay capacity.

The researchers concluded that 87% of the 68 verified historical cable fault events caused less than a 5% node impact, and cable events showed essentially zero correlation with Bitcoin (BTC) prices, or a statistically insignificant correlation coefficient of −0.02. 

They also note that the geographic diversification of BTC mining “has not materially altered infrastructure resilience,” which is consistent with physical cable topology rather than with hashrate distribution.Magazine: Big questions: Would Bitcoin survive a 10-year power outage?

Source: CoinTelegraph