📌 51% Attack Summary

A 51% attack is a situation where a single person or group gains control of more than half of the computing power on a blockchain network. With this majority, they can manipulate the system by reversing transactions or blocking new ones from being confirmed. This threatens the security and trustworthiness of the blockchain, as it allows dishonest behaviour like double spending.

🙋🏻‍♂️ Explain 51% Attack Simply

Imagine a classroom where the majority decides the rules. If over half the students team up, they could change grades or ignore fair play. Similarly, a 51% attack lets someone with most of the power control the blockchain, breaking its fairness and trust.

📅 How Can it be used?

When building a blockchain project, it is crucial to design safeguards against any one party gaining more than half the network’s power.

🗺️ Real World Examples

In 2019, the Ethereum Classic blockchain experienced a 51% attack, allowing attackers to reorganise the blockchain and double spend coins, which caused exchanges to lose funds and trust in the network to drop.

A smaller cryptocurrency called Bitcoin Gold suffered a 51% attack in 2018, where attackers gained enough mining power to reverse transactions and steal funds from exchanges, resulting in losses for both users and platforms.

✅ FAQ

A 51% attack happens when someone controls more than half of the computing power on a blockchain network. This gives them the ability to change the order of transactions or even reverse them, which means they could spend the same coins twice. It undermines the fairness and reliability that blockchains are supposed to offer.

A 51% attack is a big deal because it puts the whole system at risk. If someone can rewrite transaction history or block new transactions, it makes people lose trust in the network. This could cause the value of the cryptocurrency to fall and make people wary of using it.

While a 51% attack is possible on any blockchain, it is much harder to pull off on large networks with a lot of participants. Smaller blockchains with fewer people mining or validating transactions are more vulnerable because it takes less computing power to reach that majority.

📚 Categories

• Anti Attack
• Blockchain
• Threat Detection and Response

🔗 External Reference Links

51% Attack link

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