How much would it cost to “destroy” Bitcoin? Is it realistic?
A finance professor at an American university warned of a “real” threat to Bitcoin's integrity and calculated the cost of an attack on the world's leading cryptocurrency.
The cost of an attack on the Bitcoin blockchain is $6 billion, which is a quarter of a percent of its $2.4 trillion market capitalization. These calculations were cited by the Bloomberg business newsletter, citing research by Duke University finance professor Campbell Harvey.
According to Harvey, the so-called “51% attack” poses a threat to Bitcoin—a situation that can be exploited to gain control of a blockchain running on a PoW algorithm (Bitcoin, Bitcoin Cash, Litecoin, Dogecoin, Zcash, and others). By gaining 51% of the network's power, attackers can unilaterally alter the blockchain, changing or blocking transactions at their discretion. Double-spending of the same coins is also possible, something that should be prevented if the network is functioning properly.
One of the most recent known 51% attack attempts on major blockchain projects involved the blockchain of the largest cryptocurrency focused on confidential transactions, Monero (XMR). In the summer of 2025, Qubic claimed to have acquired more than 51% of the Monero network. While these claims raised concerns about the blockchain's security, there was no actual evidence of damage to the network's integrity.
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Cost of attack
While such an attack sounds far-fetched, it's “much more realistic,” Harvey believes, and “you could destroy the value of Bitcoin for $6 billion.” According to his calculations, the cost of a 51% attack on Bitcoin includes the cost of mining equipment—$4.6 billion—and data center construction—just under $1.4 billion. Plus, Harvey estimates additional electricity costs at $0.13 billion per week.
Harvey suggested shorting—a decline in Bitcoin—as a financial incentive. “With less than 10% of average daily trading volume, one could make a huge profit, more than enough to cover the cost of an attack against a sharp price drop,” the article states.
The expert fears that the low cost of such an attack poses a serious problem for the future of the leading cryptocurrency.
The reality of the attack
Other experts believe Harvey's concerns are exaggerated. Bitcoin mining isn't that simple, as accumulating and configuring mining equipment for such an attack would take years, notes Matt Prusak, president of mining company American Bitcoin.
Furthermore, the trader will likely have to provide a significant amount of collateral, and the exchanges where such a bet is made may suspend trading if they suspect manipulation, which will deprive the attacker of the opportunity to withdraw funds, Prusak said.
“I believe that economic feasibility kills the 51% attack thesis. I live in the real world, and it doesn't bother me,” he noted.
However, Harvey, for his part, said that for the attack to be successful, it would have to be carried out outside the US, where many safeguards against market manipulation may not be in place.
Another level of Bitcoin security
In addition to mining power, Bitcoin has an additional layer of protection against such attacks: the consensus of other market participants who operate network nodes.
In the event of a 51% attack, which somehow rewrites transactions on the network, all other market participants must accept the changes as a given—that is, effectively agree that the new, modified blockchain is the correct version of Bitcoin. This applies not only to exchanges, but also to other services and even individual cryptocurrency holders.
Hundreds of thousands of users worldwide share live updates not only on price quotes but also on the overall health of the blockchain. The Bitcoin ecosystem is complex and multi-layered, and the likelihood of an attack going undetected is close to zero.
Source: cryptonews.net
