Coin Metrics, a cryptocurrency analysis company, has recently concluded that the high costs associated with launching a 51% attack make it virtually impossible for even nation-states to disrupt the BTC and ETH networks. Such attacks, which involve dominating a network's hash rate in proof-of-work systems like Bitcoin or controlling staking in proof-of-stake networks like Ethereum, could theoretically allow attackers to manipulate the blockchain.

The research, conducted by Lucas Nuzzi, Kyle Waters, and Matias Andrade, introduces the "Total Cost to Attack" (TCA) metric to quantify the financial burden of executing these attacks. Their analysis indicates that the economic barriers to attacking Bitcoin or Ethereum effectively deter such malicious efforts, eliminating any potential benefits for would-be attackers.

Launching an attack on Bitcoin would require about 7 million ASIC mining rigs, costing around $20 billion. Given the scarcity of such a large quantity of ASIC rigs and the even higher costs of manufacturing them, the attack becomes financially unreasonable. Moreover, the most profitable double-spend attack scenario would only yield a 2.5% return on a hypothetical $40 billion investment to secure $1 billion.

Ethereum's shift to a proof-of-stake mechanism presents similar economic and logistical challenges for attackers. The study examined the possibility of a 34% attack by Lido validators on the Ethereum network, finding it would cost over $34 billion and take at least six months due to staking restrictions. The operational hurdles, including managing over 200 nodes and the substantial costs involved, such as $1 million for Amazon Web Services, make such an attack unlikely.

Nic Carter of Castle Island Ventures praised the report for its rigorous, data-driven approach to analyzing the feasibility of 51% attacks on Bitcoin and Ethereum. He highlighted the study's significance in demonstrating the robust security measures and economic disincentives that protect these leading cryptocurrencies from potential threats by nation-states.