Coinbase Report: How Many Bitcoin Could Actually Be at Risk From Quantum Computers?

[Kev5]

Coinbase's Quantum Advisory Council has published a detailed report on what a post-quantum migration for Bitcoin would actually involve, and the numbers for potential exposure are significant. The report estimates that roughly 7 million Bitcoin could eventually face some form of quantum vulnerability. This breaks down as approximately 1.7 million BTC in legacy pay-to-public-key addresses where the public key is permanently visible on the blockchain, and around 5 million BTC tied to address reuse where the public key has been exposed through multiple transactions.

The Coinbase report is careful to state that this is a future risk, not a present one. No quantum computer capable of breaking Bitcoin's elliptic curve cryptography exists today and the timeline for one that could remains measured in years to decades. The report discusses possible mitigation approaches including migration deadlines, zero-knowledge proof tools via BIP-361, and an Hourglass withdrawal rate limiter mechanism. Any migration would require broad community consensus, careful engineering, and resolution of the politically thorny question of what happens to abandoned or lost coins whose owners cannot migrate them.

Coinbase Quantum Report Warns Millions Of Bitcoin Could Face Future Security Risks

https://www.tradingview.com/news/newsbtc:952b1a80d094b:0-coinbase-quantum-report-warns-millions-of-bitcoin-could-face-future-security-risks/

[Slay40]

The 1.7 million BTC in legacy P2PK addresses being the highest-risk category makes sense because those addresses expose the public key permanently regardless of whether the owner does anything. You cannot retroactively hide an already-visible public key