A Coinbase-convened advisory council of some of the world's most prominent cryptographers has delivered its assessment on Bitcoin's quantum computing vulnerability, and on the hardest question—whether millions of exposed coins should eventually be frozen—it refuses to answer. The panel, which shared the report exclusively with CoinDesk earlier this week, includes Scott Aaronson of the University of Texas at Austin, Dan Boneh of Stanford, and Justin Drake of the Ethereum Foundation. Their core message: quantum computers do not threaten Bitcoin today, but nobody knows when they will, so planning cannot wait for a timeline.

Market Context

The debate over quantum-resistant signatures is not new to cryptography circles, but it has gained urgency as computing power advances. While Ethereum has spent years preparing for post-quantum migration through its own research initiatives, Bitcoin's community has yet to take coordinated action on the technical groundwork. The Coinbase panel's report arrives amid growing institutional focus on blockchain security and as quantum computing capabilities continue their measured expansion.

Analysis

The exposure is concentrated in Bitcoin's early architecture. Approximately 1.7 million bitcoin sit in roughly 20,000 early pay-to-public-key addresses—a format that publishes the owner's public key directly on the blockchain, leaving it vulnerable to a future quantum attack. Many of these are assumed to belong to Bitcoin's pseudonymous creator Satoshi Nakamoto and other early adopters who lost their keys, meaning they can never be voluntarily migrated to safer addresses. Another 5 million or so coins are exposed through address reuse, according to Project11, a research group tracking the issue, though most of those are believed to be active holdings in exchange wallets rather than abandoned coins.

The technical migration itself is not contentious—swapping in quantum-resistant signatures represents solvable engineering. The fight centers on what happens to unmoved coins. One camp argues for a hard deadline after which Bitcoin's current signature schemes, ECDSA and Schnorr, would no longer be accepted, rendering any unmigrated coins unspendable. Proponents warn this prevents a future attacker—potentially a sanctioned state actor—from accumulating enough bitcoin to crash the price or taint the network's legitimacy. The opposing camp calls such measures confiscation, arguing they violate the absolute property rights Bitcoin was architecturally designed to protect and could set dangerous precedents for government-mandated freezes later.

Between these positions sit several technical proposals that have emerged over recent months. Hourglass would cap how many vulnerable coins can be spent per block to prevent a supply flood if attackers ever attempted to liquidate stolen holdings. BIP-361, from developer Jameson Lopp and collaborators, would let migrated holders prove ownership after any cutoff date using a quantum-resistant proof that exposes no key material. PACTs, from Paradigm's Dan Robinson, would allow owners to timestamp a private claim now while preserving the ability to move funds later without revealing anything today. The Coinbase board notes these approaches are not mutually exclusive and could potentially be combined into a layered solution.

What the panel explicitly declines to do is pick a side in the abandoned-coins debate. "There is no correct answer," they write, "and the Bitcoin community has to decide." Their only commitments are that technical migration planning should begin immediately since it operates independently from governance questions, and that holders need clarity so the issue does not fester into market uncertainty.

Key Numbers

- 6.7 million bitcoin estimated vulnerable to future quantum attack across all exposure vectors

- 1.7 million bitcoin sitting in roughly 20,000 early pay-to-public-key addresses, many tied to Satoshi Nakamoto and lost keys

- ~5 million bitcoin exposed through address reuse, predominantly held in exchange wallets according to Project11

- Three major technical proposals currently under discussion: Hourglass, BIP-361, and PACTs