Ever wondered how much a hacker needs to execute a 51% attack on Bitcoin and Ethereum?

Crypto networks like Bitcoin and Ethereum rely on decentralization and consensus mechanisms to maintain security and integrity. However, the threat of a 51% attack looms over these networks, where a group of miners controls more than half of the network’s mining hash rate, potentially allowing them to manipulate transactions.

Understanding the cost implications of such attacks is crucial for assessing the security of these networks. Several sources provide estimates of the staggering amounts required to execute 51% attacks on Bitcoin and Ethereum. These costs encompass various factors, such as hardware, electricity, and operational expenses.

Bitcoin and Ethereum’s power play and dominance

According to recent analyses, attacking Bitcoin could range between $5 billion to $20 billion, while targeting Ethereum would necessitate over $34 billion. These figures highlight the immense financial resources needed to overpower these networks and the substantial deterrent against malicious actors attempting such attacks.

A 51% attack happens when a single network miner or group of miners controls more than 50% of a blockchain network’s hash rate. By changing with blockchain data, the attacker might theoretically prevent transactions from happening on the blockchain, change the order of new transactions, and potentially reverse earlier transactions (known as “double spending”).

However, a recent analysis found that carrying out attacks like this is monetarily unfeasible inside the present security configurations of Bitcoin and Ethereum.

Based on the following factors and in reference to December 31, 2023, an Ethereum price of $2,279, a total of 28.8 million ETH staked, and an 899,840 validator count, CoinMetrics’ computations indicate that a 34% attack on the network would require an attacker to invest approximately $34.39 billion.

In the event that the assault was to initiate on December 31, 2023, the assailant would have until June 14, 2024, to surpass the 33% threshold and seize control of the network.

An assault on Bitcoin would likewise be deemed irrational. Scholars estimate that the production costs for the assailant would exceed $20 billion, given that they would be required to produce approximately 40 million S9 units.

By December 2023, employing the most potent available ASIC, such as the forthcoming Bitmain S21, would cost approximately $5.6 billion, or about a quarter of the cost associated with utilizing the S9. This estimation comprises a unit cost of $2,240 and a production volume of 2.5 million machines.

Although this strategy is more economical than the “naive” approach, it would require manufacturer cooperation to produce at this volume and with this level of efficiency, according to the research. However, potential retaliation and disruptions in the supply chain would likely befall the assailant.

Bitcoin and Ethereum market performance

While the evaluation may hold true for prominent blockchains such as Bitcoin and Ethereum, it does not apply to the majority of networks that have emerged within the last decade.

In 2021, three 51% attacks were launched against Bitcoin SV, a blockchain that originated as a split from Bitcoin Cash and was primarily supported by Calvin Ayre and Craig Wright, both of whom are entrepreneurs. 

Previously referred to as Zcoin, the lesser-known privacy-focused cryptocurrency Firo encountered a comparable ordeal. The Ethereum Classic platform was not immune to malicious actors.

Our findings suggest that the current state of security in Bitcoin and Ethereum makes attacks economically unfeasible and provides empirical evidence of Nash Equilibrium in these networks. CoinMetrics’ Data

According to the findings of the study, Bitcoin and Ethereum have attained a level of security where the costs and risks associated with 51% attacks substantially outweigh any potential benefits. This suggests that the desirability of hostile actions diminishes in comparison to alternative approaches, such as sincere participation in the network or abstaining from attacks.

At the time of writing, Bitcoin (BTC) is worth $51,707.97, down 0.2% from an hour ago and 0.2% from yesterday. BTC’s value today is 9.7% higher than it was seven days ago.

Ethereum (ETH) is worth $2,779.24 today, down 0.3% from an hour ago and 1.0% from yesterday. The value of ETH today is 11.7% higher than it was seven days ago.

The global crypto market cap is $2.04 trillion today, down 0.62% in the last 24 hours and 74.33% from a year ago. As of today, Bitcoin’s market cap is $1.02 trillion, signifying a 49.96% domination. Meanwhile, stablecoins’ market cap is $140 billion, accounting for 6.87% of the total crypto market cap.