Blockchain explained: how a 51% attack works (double spend attack)

A 51% attack or double-spend attack is a miner or group of miners on a blockchain trying to spend their crypto’s on that blockchain twice. They try to ‘double spend’ them, hence the name. The goal of this isn’t always to double spend crypto’s, but more often to cast discredit over a certain crypto or blockchain by harming its integrity.

Here is a brief example: let’s say I spend 10 Bitcoin on a luxurious car. The car gets delivered a few days later, and my Bitcoins are transferred from me to the car company. By…