A 51% attack occurs when a single entity or group gains control of more than half of a blockchain network’s mining power or hashing rate. This majority control allows them to manipulate the network in significant ways.With this power, the attackers can double-spend coins, invalidate transactions, and prevent new transactions from being confirmed. This undermines trust in the network, as users rely on the assumption that transactions are secure and immutable.While 51% attacks are more likely in smaller networks with less mining power, they represent a serious risk to the overall integrity of any blockchain system. Major cryptocurrencies like Bitcoin have large enough networks to make such an attack extremely costly and difficult.Preventing these attacks involves increasing the number of participants in the network and enhancing the mining process’s decentralization. Ultimately, maintaining a robust and distributed network helps safeguard against potential vulnerabilities associated with control over mining capacity.