Nearly three-quarters of the world’s undersea fiber-optic internet cables — which carry around 99% of international internet traffic — would need to fail before Bitcoin experiences a significant impact, according to a study released earlier this year.
The research, first published in February and updated on March 12, was conducted by Wenbin Wu and Alexander Neumueller from the Cambridge Centre for Alternative Finance. The researchers analyzed peer-to-peer network data from 2014 to 2025 along with 68 verified submarine cable fault incidents. Using a country-level cascade model, they evaluated the resilience of Bitcoin’s underlying physical infrastructure.
According to the researchers, the study is the first long-term analysis examining how resilient Bitcoin is to failures in submarine internet cables. It also addresses a long-standing question about how the network might respond if large-scale disruptions to the global internet were to occur.
The researchers found that the critical failure threshold for random submarine cable outages ranges between 0.72 and 0.92, meaning 72% to 92% of all inter-country subsea cables would have to fail before more than 10% of nodes on the Bitcoin network become disconnected.
However, the study noted that the network is significantly more vulnerable to targeted attacks on key submarine cable chokepoints. Researchers described such attacks as “an order of magnitude more effective,” with a much lower critical failure threshold of 0.05 to 0.20.
Tor routing boosts resilience
The research also highlighted the role of Tor in strengthening network resilience. According to the study, Tor “creates a compound barrier to disruption,” largely because much of its relay infrastructure is located in well-connected European countries.
Tor functions similarly to Virtual Private Network services by routing internet traffic through a chain of volunteer-operated servers worldwide. Each step in the route is encrypted, adding layers of privacy similar to the layers of an onion.
The Bitcoin network uses Tor to obscure the locations of its nodes. The study found that around 64% of Bitcoin nodes are effectively “invisible” to researchers due to this routing method.
Researchers concluded that Tor adoption actually improves network resilience under the current distribution of relay infrastructure, rather than introducing hidden vulnerabilities. This is partly because Tor relays are heavily concentrated in countries such as Germany, France and Netherlands — all of which have extensive and redundant submarine cable connections, reducing the likelihood that cable failures would disrupt relay capacity.
The researchers concluded that 87% of the 68 verified submarine cable fault events resulted in less than a 5% impact on network nodes, indicating minimal disruption to the Bitcoin network.
They also found that cable outages showed virtually no correlation with Bitcoin’s price, with a statistically insignificant correlation coefficient of −0.02.
In addition, the study noted that the geographic diversification of Bitcoin mining has not significantly improved or changed the network’s infrastructure resilience. According to the researchers, resilience is shaped more by the physical layout of submarine cable networks than by the distribution of mining hash power.
