A 51% attack, also known as a majority attack or majority hash power attack, is a potential threat to blockchain networks, particularly those that utilize proof-of-work consensus mechanisms like Bitcoin. A 51% attack occurs when a single entity or group controls over half of the computational power on a blockchain network. With this majority control, they can potentially manipulate transactions, including double spending and rewriting transaction history. While difficult to execute on well-established networks like Bitcoin due to their large and decentralized nature, smaller and less secure blockchains may be more vulnerable to such attacks.
