Are blockchains really secure and unhackable? The 51% attack suggests otherwise

cnbctv18.com:

PoW is the original consensus algorithm in a blockchain. It confirms transactions and creates a new block in the chain. The mining hash rate is the total computational power a PoW blockchain uses to process the said transactions.

Simply put, it means how fast a miner’s machine can complete this process.Also Read | 5 things you should not do when investing in cryptocurrenciesOver the years, the 51 percent attack has gained notoriety. In 2018, Bitcoin Gold was hit by a 51 percent attack. The unknown perpetrators stole 388,000 BTG (worth $18 million) from several cryptocurrency exchanges.

The cryptocurrency suffered another similar attack in January 2020. Ethereum Classic has also been subjected to several 51 percent attacks.How does a 51 percent attack work?In normal circumstances, mining nodes create new coins on the network. Mining nodes are the computers that compete against each other to figure out the valid hashes by trial and error method.

Once someone finds the correct combination, it is approved by the network, and a newly mined block is added. This approval or agreement by the network is called consensus.However, if malicious agents gain control of over 50 percent of the network, they could: Prevent recording, validating, and confirming transactions Change the transaction processing order Double-spend the coinsDouble-spend is an issue where hackers rewrite parts of the blockchain and reverse their own transactions.Also, the 51 percent attackers can impact other miners. They can control the network’s computing power and block mining by anyone who doesn’t belong to their group.