8.

A 51% attack or a majority attack is a case where a user or group of Users control the majority.

Attackers have enough power to control most network events.

They can grab new blocks and receive rewards as they are able to prevent other minors.

They Can Cancel Transactions

Suppose Alice sent money to Bob using Blockchain. Alice is involved in the case of 51% attack, Bob is not. This transaction is placed in the block. But the attackers do not let the money be transferred.

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In addition, the minors join one of the branches and, as they possess the majority of computing power, their chain contains more blocks

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In the network, a branch that lasts longer stays, and a shorter one is rejected. So, the transaction between Alice and Bob does not take place. Bob does not get the money.

<img alt=" Minors "src =" http://cointelegraph.com/storage/uploads/view/44cc92f1c8494e2b516ba7aa6cb70be1.jpg "title =" Miners "/>

Following these steps, attackers can reverse transactions

A 51% attack is not a profitable option, it requires a huge mining power and once it is exposed to the public, the network is considered as compromise, which leads to the exit of users, which will inevitably bring down the price of cryptocurrency and, as a result, the funds lose their value.