Who has the more notorious 51% of total Hashpower in the Bitcoin network that can control the network by "fake" transactions in his favor feeds. How hard is it to carry out such an attack? 51% attack in a nutshell
In short, the 51% attack means that with more than 50% of the total computing power in the Bitcoin network, you have the possibility to inject "fake" transactions by attaching them to the blockchain. Since more than 50% of these networks are in the network, they are approved and attached to the blockchain. The attacker can then use many transactions that transfer bitcoins from other addresses to it.
More details on the 51% attack can be found in our online guide.
How much money do you need to get 51% of the Hashpower?
Suppose the attacker has not connected any miners yet. Since he wants to gain 51%, he has to add computing power until he has the majority and the rest of the network is 49%. This means:
49% = 2. 500,000 TH / s (current calculation power)After the attacker has added his calculation power, the total hash power in the network is thus: (simple three-point):
We go here from an Antinor S9, which is quite efficient with its power of 14TH / s. For the power of 2.602 000 TH / s, we therefore need 185. 857 S9 devices.Required money (miner)
An Antininer S9 currently costs 2. 010 €. The total costs for the 185. 857 units are therefore about 373.5 million euros.
Electricity costs for one day (24h)
An S9 Miner consumes 1. 375 watts, which is 33 kWh per day. The electricity price is approx. 0, 28 € per kWh. 33 kWh x 0, 28 € = 9, 24 € per day
for an S9 Miner
For 185. 867 appliances this corresponds to a daily power consumption of 6. 133. 281 kWh x 0, 28 =
first 717. 318 € per day
for 185. 857 S9 min.
€ Electricity costs per day (24h) Costs for a 51% attack for a day
With a pure hardware procurement price of 373.5 million euros and electricity costs of 1.7 million euros per day a 51% attack would cost around 375, 2 million euros per day. € Mio
Total cost of a 51% attack
Why this account is dared
We have, of course, simplified this statement very much and made many assumptions that are not always true in reality. On the one hand, it would probably be unlikely to order more than 185,000 devices at once, without the hashpower in the entire network so far. On the other hand, it can be expected that in case of a sudden feeding of huge computing capacities some miners may decide after a few days to remove their devices from the net because the Difficulty has increased so much that the Mining for them at this moment is no longer profitable enough is. What should not be forgotten: It does not necessarily take 51% of the Hashpower to carry out such an attack. They are only necessary if you want to do it with almost 100% probability. If one can already try with a much smaller proportion, the success probability is lower. Why is this so, we have explained in the article What is a 51% attack.