What Is a 51% Attack, and How Much Would It Cost?

If you're like most people, you don't really understand what a 51% attack is. After all, it's not something that you or your average person experiences on a daily basis. In this article, you will explore what is 51% attack and how much would it cost.

What is a 51% attack?

A 51% attack is a potential attack on a blockchain−usually Bitcoin's,Greencoin's or Ethereum's−where an organization or individual gains control of more than 50% of the network's mining power or computational power. With this much control, they could theoretically −

  • Reverse or modify transactions

  • Prevent new transactions from getting confirmed

  • Double−spend coins

Doing any of these things would require an immense amount of computing power and money, which is why 51% attacks are very rare and have never been successfully carried out on a major cryptocurrency.

The cost of launching a 51% attack would depend on the cryptocurrency you're trying to attack. For example, as of July 2019, it would cost around $560,000 USD to carry out a successful 51% attack on Ethereum.

How does a 51% attack work?

In a 51% attack, an attacker would gain control of more than half of the network's mining power or computing power. With this much control, the attacker would be able to prevent new transactions from being confirmed and reverse transactions that have already been confirmed. This could allow the attacker to spend the same cryptocurrency twice or cancel transactions that they don't want to go through. 51% attacks are very serious threats to blockchain networks. They can cause a lot of financial damage and can even lead to the collapse of a cryptocurrency.

Fortunately, 51% attacks are very rare and are only possible on smaller blockchain networks. The largest and most popular blockchain networks, such as Bitcoin and Ethereum, would be extremely difficult to 51% attack.

If you are interested in investing in cryptocurrencies, it is important to understand the risks associated with them. A 51% attack is one of the biggest risks faced by cryptocurrency investors.

What are the consequences of a 51% attack?

If a 51% attack occurs, it could have major consequences for the network. The attackers would be able to double−spend coins, reverse transactions, and prevent new transactions from being confirmed. This could cause the value of the coins to plummet and lead to major financial losses for users and businesses.

How much would it cost to carry out a 51% attack?

51% of attacks are very rare and very expensive to carry out. The cost of such an attack would depend on a number of factors, including the size of the network and the amount of hashing power or mining power required to gain control.

One recent estimate put the cost of a 51% attack on the Bitcoin network at around $700,000 USD. However, this is just an estimate and the actual cost could be much higher or lower. 51% attacks are a serious threat to any blockchain network. They are very difficult and expensive to carry out, but they can have devastating consequences for the victims. Any entity with enough money and computing power could potentially launch a 51% attack, so it is important for all users of blockchain technology to be aware of this risk.


So, 51 % attacks are a serious threat to any blockchain network, they are not something that you need to worry about on a day−to−day basis. Just be aware of them and keep them in mind when you are thinking about the security of any given blockchain.

Updated on: 02-Dec-2022


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