It's quite easy for the low cap coins to be 51% attacked but bitcoin's sheer size makes it nearly impossible. The amount of money that would be needed to generate enough hashrate wouldn't even make sense financially. Maybe if a group of billionaires wanted to see bitcoin die it could be done but they would not make any money off their attack.
The amount of money required may not be as much as you think.
One needs a little less than 1 hour to 30 minutes to double spend their entire btc amount.
So all one would need to do is rent the needed hashrate for 1 hour, to devastate btc.
IE:
https://www.coindesk.com/this-college-freshman-is-out-to-51-attack-your-cryptocurrency
Quote
While going through the exchange process costs more,
the 51% attack has still become quite economical due to the rise of cloud computing.
According to geocold51, without access to cloud mining, an attack like he did on bitcoin private would have cost him about $100,000 in hardware.
Geocold51 estimates he spent $100 to get to the point where he could have done a demonstration double spend on bitcoin private,
“Nicehash and the ability to rent hashing power fundamentally changes the landscape of 51% attacks,” geocold51 told CoinDesk, adding:
“If there’s not a lot of hashing power to secure it, but there is a lot of value associated with it, that’s where you can do a 51% attack.”
the 51% attack has still become quite economical due to the rise of cloud computing.
According to geocold51, without access to cloud mining, an attack like he did on bitcoin private would have cost him about $100,000 in hardware.
Geocold51 estimates he spent $100 to get to the point where he could have done a demonstration double spend on bitcoin private,
“Nicehash and the ability to rent hashing power fundamentally changes the landscape of 51% attacks,” geocold51 told CoinDesk, adding:
“If there’s not a lot of hashing power to secure it, but there is a lot of value associated with it, that’s where you can do a 51% attack.”
As BTC Hashrate drops , a rented 51% attack becomes more feasible every day.
One only needs to rent for 1 hour to pull one off.
