The 51 percent attack is featured in the finale episode of the Silicon Valley Hollywood movie. While it features a real threat where miners can attack the network by hijacking a more than 50 percent of the network, it is exaggerated.
The “Fifty-One Percent” is the name of the Silicon Valley movie season finale and it features an organized group of cryptocurrency miners who crowd a blockchain network to reach 51 percent consensus and then hijack the network and disrupt it. According to the trailer, a group of miners attack a blockchain network called Pied Piper blockchain network. However it attempt to delete all the network users, developer apps and then crash the coin.
And while such a threat where miners control more than 50 percent to execute hidden motives. Thus, their operations are only limited according to Cornell cryptographer Emin Gün Sirer.
“Miners at 51 percent or more have a lot of powers, but they do not have the ability to change the actual rules of the system, nor can they usurp funds. They can rewrite the existing blockchain in a limited fashion. Also they cannot introduce transactions that don’t already exist. And they can omit any transaction that they want. However, they certainly cannot change any of the existing rules”.
In the real world, this type of attack has been deployed against Krypton and Shift which are clones of Ethereum. Both were attacked by a group called 51 Crew. After holding a majority of coins in both attacks, the crew sent the coin creators a ransom note saying serious damage would result if they were not paid.
And in the real world of blockchain, cryptocurrency projects are aware of the fact that miners who control more than 50 percent of the network can bring chaos on the network when acting as a group with hidden agenda. They can stop payments between users, and can even reverse certain completed transactions. So as to appear as if the coin holders spent them.
Also, rewriting transactions can ruin legitimacy of all transactions and end up killing the coin, especially for smaller coins. However, attackers would not be able to delete all users and apps according to Cornell cryptographer Emin Gün Sirer.
It is a problem whose solution is not clear although different companies continue to implement different solutions. Therefore, the episode does good work to highlight a real problem that deserves some attention inside of blockchain, even though it is exaggerated.