The question of how resistant the Bitcoin network is to physical infrastructure has long been a topic of debate. Last week, a study published by Cambridge researchers provided an interesting answer: to truly cripple the network, between 72% and 92% of the submarine cables connecting continents worldwide would need to be cut simultaneously.

The research analyzed 11 years of peer-to-peer network data and compared it with 68 real cable failure events. The findings are quite reassuring: random cable failures have almost no impact on Bitcoin. Over 87% of the incidents examined affected less than 5% of nodes. Even the largest event in March 2024 off the coast of Ivory Coast caused only a 0.03% global impact.

But the most intriguing part begins here. While random failures are harmless, targeted attacks tell a very different story. A coordinated assault on critical cables serving as bridges between continents could reduce the threshold to just 20%. Even more concerning is the targeting of five major hosting providers: (Hetzner, OVH, Comcast, Amazon, and Google Cloud). In this case, disabling just 5% of routing capacity would suffice.

The difference between natural random events and state-level targeted attacks essentially presents two distinct threat models. One is a scenario where Bitcoin can comfortably survive. The other poses a serious risk.

It’s also interesting to see how resilience has evolved over time. Between 2014 and 2017, the network was geographically diverse and at its most resilient. Then, from 2018 to 2021, it rapidly centralized, becoming the weakest point, especially due to increased mining concentration in East Asia. In 2021, China’s mining ban redistributed the network, partially restoring resilience.

Perhaps the most surprising finding concerns TOR usage. Currently, 64% of Bitcoin nodes operate over TOR, hiding their physical locations. The initial thought was that this privacy might make the network more vulnerable. But the research showed the opposite. TOR infrastructure is concentrated in countries like Germany, France, and the Netherlands—areas with dense submarine cable connections. As a result, TOR usage contributes to resilience by between 2% and 10%.

This exemplifies how the Bitcoin community has unintentionally evolved toward a censorship-resistant infrastructure. After events like Iran’s internet shutdown in 2019, the Myanmar coup, and China’s mining ban, TOR usage increased. Without any central coordination, the network has taken self-protective measures. And in doing so, it has also become more robust against physical attacks.

With the Strait of Hormuz currently closed and tensions in the Middle East, the risk of submarine cable cuts is no longer purely theoretical. However, the study shows that unless these cables are deliberately targeted, probably nothing will happen. Random failures cannot break Bitcoin. But a coordinated, targeted attack would tell a different story.