A report backed by Coinbase says today’s quantum computers are still not capable of breaking the cryptography used by Bitcoin, Ethereum, and similar blockchain networks. That does not remove the problem. The authors say the engineering demands of building a quantum machine with the required scale and error tolerance remain severe, yet Google researchers have projected that a sufficiently advanced system could eventually pose a real threat to Bitcoin’s cryptographic security.
Current machines are still below the danger threshold
The report makes clear that the immediate risk is limited because existing quantum hardware is not powerful enough to compromise the core cryptographic foundations of major networks. Even so, the subject is now being treated more seriously in research and technical circles. The Ethereum Foundation is exploring stronger forms of digital signatures, while teams working on platforms such as Solana are building quantum-resistant wallets and related protections.
Migration may take years across wallets, exchanges, and networks
The report argues for a carefully managed transition instead of a rushed industry response. The US National Institute of Standards and Technology, or NIST, currently recommends moving to quantum-resistant cryptography by 2035, but the report warns that this target may still be optimistic. In the report’s words, “It is not wise to expect this to become an urgent matter; safely migrating networks, wallets, and exchanges could take years.”
One of the biggest complications is the need to migrate millions of crypto wallets, including wallets tied to forgotten or inactive holdings. The authors add that Bitcoin wallets with previously exposed public keys may be especially vulnerable in the nearer term. That makes the issue broader than protocol design alone, because legacy assets also have to be moved safely.
Post-quantum signatures could raise block sizes dramatically
NIST is already reviewing post-quantum cryptographic systems as part of its standardization work, and those systems are available today. Still, the report says they can require far larger data footprints and much higher processing costs than traditional cryptography. By the report’s estimate, adopting quantum-proof digital signatures could increase block sizes by as much as 38 times, sharply increasing storage needs, data transfer costs, and the overall processing burden on blockchains.
The authors do not present a single universal fix. Instead, they recommend hybrid migration models that use current cryptographic methods alongside next-generation approaches, allowing networks to transition in phases and adjust over time. The report ends with a simple conclusion: “The right time to begin preparations is now.”