Can Facebook’s Libra Cryptocurrency Suffer a ‘34% Attack?’

Today, Facebook unveiled its Libra cryptocurrency. The company also released a whitepaper. In it, the team lays out all the details about Facebook’s future digital currency. What seems to be flying under the radar, though, is how little it takes for Libra’s network to be disrupted. We’ve all heard about 51% attacks on proof-of-work consensus systems. If 51 percent of miners, as a group, decide to collude, they could effectively stop transactions, double-spend, and bring the entire network into chaos. However, it’s exceptionally hard (and expensive) to pull off such an attack on top-tier cryptocurrencies. However, upon investigation, it seems that Libra can also be subject to something similar. In fact, it takes only one-third of all nodes to disrupt the entire network. It’s spelled out right in Facebook’s Libra whitepaper, which claims that “This approach builds trust in the network because BFT consensus protocols are designed to function correctly even if some validator nodes — up to one-third of the network — are compromised or fail.”

So there you have it. Libra is prone to what could be called a ‘34% attack.’ But how likely is such an attack anyway? By all estimates, not likely at all. Costing around $10M to run a node for Libra, for any party to attempt such a move would be akin to suicide. It would also be far too expensive, and the benefits of such an attack would not be worth it. Still, the fact that Libra only requires a third of validator nodes to ‘overthrow’ its network is worrying. So many people complained about 51% attacks against proof-of-work coins: they should have the same criticism for Libra. Just because it’s backed by a multinational tech conglomerate does not make it more ‘safe.’ Do you believe the Libra is susceptible to attacks? Let us know your thoughts below.