The 51% attack

One important concept covered is the 51 percent attack, which is an attack that can be carried out by an individual or group that controls the majority of computational resources in a blockchain network.

This attack allows the attacker to control the blockchain and potentially perform double-spend transactions, where the same cryptocurrency is spent twice.

Proof of work operates based on majority vote, computing power determines how many "votes" an individual has. If and individual or group own the majority of votes, they control the blockchain