How much computing power and money is required to carry out a 51% attack on a blockchain like that of Litecoin which uses PoW as its protocol?
Blockchains using the PoW consent protocol (Proof of Work) use the computing power of machines to secure data and the network that has more hash power corresponds to a network that is often more secure.
As for the large blockchains, the power they have is really huge and it would take a lot of money and a lot of electricity to attempt a 51% attack, which involves obtaining most of the network power and then modifying the block history to one’s advantage.
For simplicity let’s round up the various results and take as a reference point 153 TH/s to simulate the cost of a 51% attack on Litecoin. These are the technical parameters:
- Bitmain Antminer L3+ 504 MH/s, maximum cost $2200, power 800 Watt;
- Cost per KWh of $0.12;
- Price value LTC $64.
From this data, the cost of a 51% attack on Litecoin can be calculated. First, it is necessary to transform the TeraHash into MegaHash, so as to calculate how many L3+ machines are needed:
153 TeraHash = 153000000 MegaHash
Now it is necessary to divide that computing power by that of a single machine, knowing that each machine has a power of about 504 MH/s:
153000000 / 504 = 303572 number of Antminers to buy
So we have to buy over 300 thousand Antminer L3, of which we know that the maximum price is $2200 per unit:
303572 * 2200 = 667858400 cost in dollars of the Antminers
This would mean that over $600 million would be needed to buy all the necessary equipment, as well as a stadium-sized garage to fit it all.
Now that the machines are in place, they have to be connected to the power supply and, as previously mentioned, the average electricity cost is $0.12 KWh; each machine has a power of about 800 Watts, so $4.80 will be spent in 24 hours.
800 * 303572 = 242857600 (242 Megawatts)
4.80 * 303572 = $1457146 electricity cost
So we need at least 242 Megawatts: note that a football stadium during a game consumes 24 Megawatts. To this has to be added the cost of electricity which is just under $1.5 million a day, which means that only the operating expenses would be:
667858400 + 1457146 = 669315546 total cost in dollars
At this point, since it is clear that the cost arrives at just under $700 million, it is now possible to see how many Litecoin (LTC) can be mined. A machine produces 0.008560 LTC in one day, so it will be enough to multiply the number of machines by the daily production from which should be subtracted the cost of electricity in order to understand the profit:
0.008560 * 303572 = 2599 LTC
2599 * 64 = $166336 profit from the sale of the LTC
1457146 – 166336 = 1290810 loss on LTC profit
In short, to carry out an attack with the power necessary to hold the majority of the network, it would take just under $700 million.
In short, an exorbitant cost and that, among other things, would lead to an economic loss, especially because the value of the crypto attacked would inevitably go down, resulting in a further loss.