In a recent technical document released by Ethereum, co-founder Vitalik Buterin has stated that a solution to probably the most potent future threat to Ethereum and other decentralised networks, ‘The 51% attack’, has been invented.
According to Vitalik, the possibility of 51% attack has been neutralised with the help of an algorithm that makes it mandatory for an attacker(s) to take control of more than 99% of the nodes on Ethereum network, which is almost impossible, given the exorbitant computational and monetary requirements for enforcing the attack.
What is a 51% attack?
51% attack is a hypothetical, yet possible, attack on a blockchain network. The attack requires a group of miners, also called validators, to control 51% or the number of nodes on a blockchain network. And because ‘nodes’ mean ‘computational resources’ or simply ‘computers’; by doing so, attackers can control more than 51% of the computational power of the network, some of the worst consequences of which could be reverse transactions or Double Spend, preventing confirmations for new transactions, and more; thereby disrupting the core functionality of the network.
The Russian-Canadian programmer proposes an algorithm, which introduces ‘Independent Observer Nodes’. An independent observer node is a type of node, which is a client run by a user on the blockchain network. This node is in charge of observing any abnormalities in the entire Ethereum network with a fault tolerance of just 1%, which means it can detect any unusual change in the network if less than 99% of nodes are causing it. In other words, to change anything in the network, attackers will have to hack 99% or the number of nodes.
So what changes for Ethereum?
Before the proposal of deploying an independent observer node, the fault tolerance of the Ethereum network was 49%, which was still considered unassailable. So basically, Ethereum is en route becoming the most secure decentralised network in terms of nodal attacks.