Attacks on Bitcoin and Ethereum now 'economically unfeasible': research

The current security models for Bitcoin BTC -0.77% and Ethereum ETH +0.53% make 51% and 34% attacks, respectively, “economically unfeasible,” according to a new research paper published on Feb. 15.

A 51% attack is an attempt by an entity to gain control of more than half of a blockchain’s mining hash rate, theoretically allowing it to alter the distributed public ledger maliciously. Similarly, a 34% attack attempts to manipulate the consensus of the ledger (in proof-of-stake or BFT networks) to approve or disapprove specific transactions by acquiring network stake.

According to the researchers, it would have cost an estimated $34.39 billion to 34% attack the Ethereum network on Dec. 31, 2023 — when ether was priced at $2,279 per coin — and it would take until June 14, 2024, for the attacker to successfully gain the required control over the network.

In the case of Bitcoin, different scenarios prove similarly unfeasible. For example, it would cost an attacker more than $20 billion to produce the number of ASIC mining units needed to gain majority control over the foremost blockchain’s hash rate — an impossibility due to limited microprocessor availability.

Alternatively, an attacker would need to collude with hardware manufacturers — an unlikely scenario that would also run into supply-chain issues.

Electricity costs to run the mass amount of machines would also prove prohibitive.

The findings lead the researchers to conclude that "the security of Bitcoin and Ethereum has evolved to a point where the costs and risks associated with attacks far outweigh any potential benefits."