What is a 51% Attack?

A 51% attack, also known as a majority attack or majority hash power attack, occurs when a single entity or group of entities controls more than 50% of the total computational power or mining power of a blockchain network. This enables the attacker to manipulate transactions, reverse transactions, or double-spend coins, undermining the security and integrity of the network. 51% attacks are more likely to occur on smaller and less secure blockchain networks, highlighting the importance of decentralization, consensus mechanisms, and network security in preventing such attacks.