Bitcoin Faces Quantum Computing Threat: Can Crypto Survive the 9-Minute Attack?

The rise of quantum computing has become a critical challenge to Bitcoin’s cryptographic foundation, pushing developers to accelerate defensive upgrades. While no current quantum machine can break Bitcoin, new research has raised the risk from theoretical to an urgent priority for the cryptocurrency community.

Google research highlights a fast potential breach

Research released by Google this week suggests that a sufficiently advanced quantum computer could compromise Bitcoin’s underlying cryptographic protection in fewer than nine minutes. That window is shorter than the typical time needed to confirm a Bitcoin transaction block, and industry experts project such capability could arrive as soon as 2029.

How much bitcoin could be exposed

Approximately 6.5 million BTC remain in addresses that would be directly vulnerable to quantum attack. Of that total, about 1.7 million BTC are held in legacy address types that have already revealed their public keys through on-chain activity. The holdings include coins believed to belong to Bitcoin’s pseudonymous founder, Satoshi Nakamoto.

Why quantum computing changes the threat

Bitcoin’s security relies on elliptic curve cryptography. Conventional computers would require billions of years to defeat the encryption, but a quantum computer could potentially reverse the mathematical operations linking public keys to private keys within minutes.

Two main quantum attack models are described in the research and related discussion: long-exposure attacks, which target bitcoin that has remained in vulnerable addresses for extended periods, and short-exposure attacks, which involve intercepting transactions while they wait for confirmation in the mempool.

Developer solutions under consideration

BIP 360

BIP 360 aims to remove permanent on-chain storage of public keys by introducing a new address structure designed to provide quantum attackers with no exploitable data. The proposal is limited to future transactions and cannot protect the roughly 1.7 million BTC whose public keys have already been exposed.

SPHINCS+ (SLH-DSA)

SPHINCS+, also designated as SLH-DSA, is a quantum-resistant signature protocol based on hash functions rather than elliptic curve mathematics. The National Institute of Standards and Technology standardized the approach in August 2024. A key drawback is signature size: about 8 kilobytes compared with Bitcoin’s existing 64-byte signatures, which could increase transaction costs.

Lightning Network commit/reveal mechanism

Tadge Dryja, co-creator of the Lightning Network, has proposed a commit/reveal mechanism that splits transactions into two stages. This design is intended to prevent quantum attackers from stealing funds through fraudulent competing transactions in the mempool. It is described as an interim measure while longer-term defenses are developed.

Addressing already-exposed coins

Hunter Beast’s Hourglass V2 proposal targets the approximately 1.7 million BTC already exposed via revealed public keys. The plan would limit withdrawals from vulnerable addresses to one bitcoin per block, aiming to throttle potential mass liquidation after a quantum breach. Some in the Bitcoin community oppose the idea, arguing that such restrictions conflict with the principle of unrestricted spending rights.

Investor warning and governance constraints

On the All-In podcast, venture capitalist Chamath Palihapitiya said projections for viable quantum threats have narrowed from 25 years to about seven. He warned that non-governmental actors would likely target Bitcoin first to extract value before any broader market disruption.

None of the protective measures described have been implemented yet. Because Bitcoin is governed through decentralized consensus, any protocol upgrade would require agreement among developers, mining operations, and node operators.