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Give me the basics

A 51% attack is when a group of miners in a cryptocurrency network control more than 50% of the network’s mining power. This allows them to potentially manipulate transactions by double-spending or excluding certain transactions. The attack is called “51%” because the attackers need to control a majority of the network’s computing power to successfully carry out the attack. A 51% attack is rare, but it can be detrimental to a cryptocurrency’s reputation and value.


In-depth explanation

A 51% attack is a potential security threat that can occur in a blockchain-based cryptocurrency network. In a blockchain network, transactions are verified and added to the blockchain by a network of nodes or miners who use their computing power to solve complex mathematical problems. A 51% attack occurs when a single entity or group of entities controls more than 50% of the network’s computing power, giving them the ability to potentially manipulate transactions and undermine the security of the network.

To understand how a 51% attack works, it’s important to understand how transactions are verified in a blockchain network. When a transaction is initiated, it is broadcast to the network and added to a pool of unconfirmed transactions. Miners then compete to verify the transaction and add it to the blockchain. To do this, they use their computing power to solve a complex mathematical problem known as a hash function. The first miner to solve the problem is rewarded with newly minted cryptocurrency and the transaction is added to the blockchain.

In a 51% attack, a group of miners controls more than 50% of the network’s computing power. This means that they have a greater chance of solving the mathematical problem and adding blocks to the blockchain than the rest of the network. The attackers can use this advantage to manipulate the blockchain by excluding certain transactions or double-spending, which means spending the same cryptocurrency twice. This can lead to a loss of trust in the cryptocurrency, as it undermines the security and immutability of the blockchain.

A 51% attack is a rare occurrence, as it requires a significant amount of computing power to control the majority of the network. However, it is not impossible, especially in smaller blockchain networks with fewer miners. Additionally, the cost of carrying out a 51% attack has decreased over time as the computing power required to control the majority of the network has become more affordable