Google has released new research indicating that future quantum computers could break the cryptographic systems underlying Bitcoin with significantly fewer resources than previously estimated. The findings suggest a potential acceleration of quantum-related risks to blockchain security.
According to the report, cracking 256-bit elliptic curve cryptography may require fewer than 500,000 physical qubits, roughly 20 times less than earlier projections. Under certain assumptions, such an attack could be executed in minutes using superconducting quantum systems, potentially faster than the time required to confirm a Bitcoin transaction.
The vulnerability stems from how Bitcoin transactions expose public keys during processing. A sufficiently advanced quantum computer could derive the corresponding private key and submit a competing transaction with a higher fee before confirmation, effectively intercepting funds.
The research highlights that millions of bitcoins, including early-era holdings, could be exposed if quantum capabilities reach the required scale. While such systems are not yet operational, the trajectory of quantum development is prompting increased urgency.
Google is advocating for a transition to post-quantum cryptography, a class of encryption methods designed to resist quantum attacks. The company has outlined a timeline targeting migration by the end of the decade and is engaging with industry and government partners to coordinate mitigation strategies.
