Google just told the Bitcoin and cryptocurrencies industry it has less time than it thought to prepare for the quantum computing influence. In a whitepaper published March 31, Google Quantum AI researchers demonstrated that breaking the elliptic curve cryptography protecting bitcoin, ether and most major cryptocurrencies could require fewer than 500,000 physical qubits on a superconducting quantum computer. That’s roughly a 20 times reduction from prior estimates, which pegged the figure in the millions.
The paper carries serious institutional weight. Its coauthors include Justin Drake of the Ethereum Foundation, Dan Boneh of Stanford, and six Google Quantum AI researchers led by Ryan Babbush and Hartmut Neven. Google says it engaged with the U.S. government before publishing and names Coinbase, the Stanford Institute for Blockchain Research, and the Ethereum Foundation as collaborators.
It’s important to understand that no quantum computer can execute this attack today. Google’s most advanced chip, Willow, has 105 qubits. But the distance between current hardware and a machine capable of cracking bitcoin’s cryptography is shrinking faster than projected.
“My confidence in q-day by 2032 has shot up significantly,” Drake, who joined the paper as a late coauthor, wrote on X. He estimates at least a 10% chance that a quantum computer recovers a private key from an exposed public key by that year.
The findings suggest attackers could one day steal bitcoin mid-transaction, challenging assumptions that the threat is decades away.
Breaking Bitcoin’s blockchain with quantum computers may not be as difficult as once thought, and Bitcoin’s Taproot technology, which enables more efficient, private transactions, may be partly to blame, Google’s Quantum AI team said Monday in a blog post and newly published whitepaper.
The team said the computing power required to break Bitcoin’s security may be far lower than previously assumed, raising fresh questions about how soon quantum threats could become a reality.
In a new whitepaper, researchers found that cracking the cryptography used by Bitcoin and Ethereum could require fewer than 500,000 physical quantum bits, or qubits, well below the “millions” often cited in recent years.