If hackers felt like it, they could split bitcoin in two.

It wouldn’t even be that hard, according to research from 2017. Thanks to insecure technology underpinning the internet, someone with the right credentials could exploit the Border Gateway Protocol (BGP) by faking their identity and confusing the network into sending floods of data somewhere it shouldn’t. “The internet’s biggest security hole,” as it’s been called, has been used for everything from snooping on government emails to stealing cryptocurrency.

As far as splitting bitcoin, the attack is as bad as it sounds. If executed successfully, one chunk of the network would be completely sliced off from the other. No one could communicate and send transactions to people who are a part of the “other” network.

That’s where researchers from the prestigious Swiss university ETH Zurich hope to help. As described in a new white paper, they’ve invented a relay network called SABRE that they hope will one day be built on top of bitcoin.

With the same name as the curved blade common in the Napoleonic era, SABRE sounds like it would be used to slice bitcoin in half. Instead, it hopes to do the opposite. Rather, the planned network would (metaphorically) wield a saber against impending attackers, stopping them in their tracks.

Eth Zurich computer network researcher Maria Apostolaki told CoinDesk:

“SABRE is a small relay network whose nodes are strategically located such that they remain connected to each other and connected to as many regular nodes as possible, even in the presence of a AS-level adversary that hijacks traffic.”

This network would “render the partition ineffective,” she said.

When SABRE is used, the risk of a split goes down, the researchers claim. Without SABRE, it’s possible for an ISP to attack and partition bitcoin with only a “small” routing attack. But, according to the researchers’ simulations on a group of five nodes, there’s only a 3.1 percent chance probability of the attacker could hijack the network and partition it. The probability also decreases as the number of nodes increases.

To be presented at The Network and Distributed System Security Symposium this month, the proposed layer is the result of years of research. Apostolaki has been researching this specific issue since 2016 since “blockchain applications are very common nowadays making research on their routing characteristics very impactful.”

The attack

The attack strikes at the root of the internet.

Every time you click a webpage, you’re unknowingly using BGP, an internet protocol that helps get data from Point A to Point B. Say you want to get to CoinDesk.com. Your…