According to CryptoPotato, a recent study suggests that executing 51% attacks on Bitcoin and Ethereum is financially unviable within their current security setups. A 51% attack occurs when a single network miner or group of miners controls more than half of a blockchain network’s hash rate, potentially enabling them to block transactions, alter the sequence of new transactions, and revert past transactions by tampering with blockchain data.
CoinMetrics' calculations, based on an Ethereum price of $2,279, a total staked ETH amounting to 28.8 million ETH, and a validator count of 899,840 validators, indicate that an attacker would need around $34.39 billion to execute a 34% attack on the network. Attacking Bitcoin would also prove to be equally far-fetched, with researchers estimating that the attacker would face production expenses of over $20 billion.
The study concluded that the security measures of Bitcoin and Ethereum have reached a level where the costs and dangers linked with 51% attacks significantly outweigh the potential benefits. It indicates that hostile actions become less appealing when compared to alternative strategies like honest engagement in the network or refraining from attacking. However, the assessment may not hold true for many other networks that have surfaced in the past decade, such as Bitcoin SV, Firo, and Ethereum Classic, which have experienced instances of 51% attacks.