The 51% attack is the scarecrow of blockchains that make use of proof-of-work. But Bitcoin (BTC) would now be completely safe from this attack vector, according to a new report from CoinMetrics. The analysis also notes that Ethereum (ETH) is safe from a 34% attack.
Bitcoin would be completely safe from a 51% attack
It’s one of the arguments sometimes used by Bitcoin (BTC) detractors: its potential vulnerability. The main possible flaw for the world’s largest cryptocurrency has indeed been historically identified: the so-called 51% attack. This is a scenario where attackers manage to control more than half of the computing power (hashrate) of the Bitcoin network.
We’ve known for a long time that the costs of such an attack would be very high, and a report from CoinMetrics puts the figures exactly. The conclusion is clear: a 51% attack on Bitcoin is “economically unfeasible”.
CoinMetrics simulated several scenarios: in one, a malicious actor would get his hands on 51% of the ASICs currently running on the network. In another, he would choose to build his own machines. Either way, the cost is astronomical:
6/ Accounting for all attack scenarios and factoring in OpEx (electricity), it has never been this expensive to attack Bitcoin, from the “naive” scenario of 5B all the way to 22B USD: pic.twitter.com/tBnAy7jLlU
– Lucas Nuzzi (@LucasNuzzi) February 15, 2024
CoinMetrics also mentions a scenario where a nation-state chooses to use all its resources to destroy the Bitcoin network. According to the analysis, this is now simply impossible:
“We see no way in which a nation-state could continuously attack via a 51% attack, if the goal is to destroy the network. [In the end, the network always survives. “
What then of attackers who would instead mobilize resources to monopolize the funds present on the network? In the most optimistic scenario for attackers, they’d manage to walk away with $1 billion… But they’d have to spend $40 billion to conduct the attack, so they wouldn’t be able to profit from it, far from it.
Ethereum also safe from danger
This is also the case with Ethereum, for which the 34% attack is also a recurring scarecrow. The threat has been increasingly raised with the arrival of Liquid Staking Derivative (LSD) providers, such as Lido Finance. If an attacker could theoretically get his hands on 34% of ETH staking, he could threaten the network.
Again, we already knew this was an unlikely threat, but CoinMetrics has just confirmed that, economically, it’s simply not feasible :
“We estimate that an attack on Ethereum would take 6 months […] and cost over $34 billion. The attacker would have to manage more than 200 nodes. “
Hence a particularly optimistic conclusion to the analysis:
“This is the first empirical evidence […] on Bitcoin and Ethereum that antagonistic actions become unattractive when compared to other strategies, such as participating honestly in the network or refraining from participating. “
In other words: no player would have any interest in attacking the Bitcoin and Ethereum network, since it wouldn’t be profitable, and they wouldn’t succeed in bringing the networks down. Users of these two blockchains can therefore rest assured: these two types of attack are unlikely to occur.
