Coinbase, custodian of about 5% of bitcoin, says quantum migration can take years
Coinbase, which says it custodies roughly 5% of all bitcoin, argues a new signature algorithm will not make the network quantum-resistant. Its list adds dormant coins, block space, MPC custody and full-node validation, and it wants work to start now.
The Investor · Invest desk
Key figures: a $15 million combined pledge by Coinbase, BlackRock and Strategy toward quantum-proofing bitcoin; roughly 5% of all bitcoin custodied by Coinbase, as Coinbase says; a 5% share equals one coin in every 20.
| Figure | Value | Note | Claim |
|---|---|---|---|
| Combined consortium pledge with BlackRock, Strategy | $15 million | 18 | |
| Share of all bitcoin Coinbase custodies, roughly | 5% | as Coinbase says | 1 |
| Share as one coin in every | 20 coins | 21 |
What happened
- In a blog post published Tuesday, Coinbase wrote: "Bitcoin consensus changes and ecosystem migrations can take years."
- The exposure it is guarding against is a quantum machine deriving a private key from an exposed public key, a hypothetical milestone the industry calls Q-Day.
- Coinbase floated a staged 1-of-2 spend path that lets the same funds move with either a classical key or a quantum-safe one during the transition.
- It called dormant, lost and Satoshi-era coins a separate governance problem and said any rescue mechanism must itself be quantum-safe.
Why it matters
- What it costs cost The implementation list lands on whoever writes signing software, custodians included: constant-time verification, cross-platform consistency, predictable signing and resistance to random-number failures.
- Who has to decide decision Custodians and wallet providers get a timing choice: on a hybrid path they can move before the community settles when legacy signatures get restricted.
- What it limits constraint In our view the block-space limit and the custody risk pull against each other: stateful schemes may be smaller and faster, but a reused signing state allows forgery, and Coinbase wants a stateless option kept.
Next story · Invest · 2d ago
Coinbase wants Bitcoin's quantum-resistant wallets designed now because migration takes yearsConfirmed3 publishers
We think the multi-year framing is right for custodians, because Coinbase's conditions split into problems an engineering team can close and one it cannot close alone. The closable ones are properties of a container. P2MR under BIP-360 and P2TRv2 could let post-quantum signature systems be introduced or replaced without a new output format each time [5], and Coinbase wants any scheme checked for compatibility with the MPC key-splitting that custodians use [15]. That second ask is self-interested, as it should be: 5% of supply is one coin in every 20 [21], and Coinbase says it custodies that share [1].
The problem that cannot be closed by engineering is the pile of coins that never move. Bitcoin holds old outputs with exposed public keys, reused addresses, dormant holdings and funds whose private keys may already be lost [14], and no wallet upgrade reaches an owner who never signs again. Coinbase said that debate should not delay work on post-quantum signature support [10]. In our view that puts the two tracks on separate clocks, and the slower one sets how much of the supply the faster one ends up protecting.
There are two ways this plays out differently. The threat may stay hypothetical for longer than the plan assumes: the coverage describes no immediate quantum attack on bitcoin [11], and Coinbase's case is that waiting for an announced cryptographically relevant quantum computer would leave too little time to respond [3]. Or the post may carry less weight with developers than its length suggests. Decrypt described it as less a mandate than a set of requirements from one of the network's largest stakeholders [20], so developers could adopt the container and set the custody asks aside.
The only dollar figure in the coverage is consortium money. Coinbase joined the Bitcoin Security Consortium in July alongside BlackRock and Strategy, with a combined $15 million pledged toward quantum-proofing bitcoin [18], after convening its own quantum advisory board in January [17]. Neither account includes a migration budget, a timetable or the signature scheme Coinbase would choose.
We would be wrong if BIP-360 or a similar container reaches activation quickly and the MPC and stateless-signing questions close without redesign. The "can take years" estimate would then describe Coinbase's caution.
What to watch
- Whether bitcoin developers move a container design such as BIP-360 toward activation, and whether the MPC and stateless-signing asks show up in it.
- Any concrete proposal for dormant and Satoshi-era coins, which Coinbase says is a governance problem separate from signature support.
- Whether the Bitcoin Security Consortium's $15 million pledge is tied to named work or a published migration cost estimate.
Information, not investment advice. This story is general information about companies and markets, drawn from cited reporting. It is not a recommendation to buy, sell or hold any security; check the cited sources before acting.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence50
- Adoption
- Not scored
- Hype gap+10
- Incentives55
- Confidence72
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
Coinbase says it custodies roughly 5% of all Bitcoin.
- [2]
In a blog post published Tuesday, Coinbase wrote: "Bitcoin consensus changes and ecosystem migrations can take years."
- [3]
Coinbase urged developers to start preparing now, warning that waiting for the announcement of a cryptographically relevant quantum computer would leave too little time to respond.
- [4]
Coinbase said any transition would need to protect existing and newly created coins, fit Bitcoin's limited block space, work for ordinary wallets and institutional custody, and offer a migration path for coins that never move.
- [5]
Coinbase pointed to designs including P2MR under BIP-360 and P2TRv2, which could potentially allow post-quantum signature systems to be introduced or replaced without creating an entirely new output format every time.
- [6]
Coinbase floated a staged 1-of-2 construction letting the same funds be spent with either a classical key or a quantum-safe one during the transition.
- [7]
Coinbase warned that some stateful post-quantum signature schemes, while potentially smaller and faster, introduce operational risks, because reusing a signing state can make forgery possible, which is difficult for institutions running distributed signing systems across multiple servers and locations.
- [8]
Coinbase wants bitcoin to retain a stateless signing option.
- [9]
Coinbase said dormant, lost or exposed coins, including Satoshi-era holdings, should be treated as a separate governance problem, and cautioned that any rescue mechanism must itself be quantum-safe so an attacker who only knows an exposed public key could not exploit it.
- [10]
Coinbase says the debate over dormant coins should not delay work on post-quantum signature support.
- [11]
There is no immediate quantum attack on bitcoin described in the coverage.
- [12]
A sufficiently powerful quantum machine could, in theory, derive a private key from an exposed public key and drain the funds, a hypothetical milestone the industry calls Q-Day.
- [13]
Coinbase argued that any transition must protect exposed coins, fit within bitcoin's limited block space, preserve full-node validation, and work for both institutional custody and everyday users.
- [14]
Bitcoin contains old outputs with exposed public keys, reused addresses, dormant holdings, and funds for which private keys may already be lost.
- [15]
Coinbase said whatever scheme Bitcoin adopts should be compatible with multi-party computation, the key-splitting technique custodians like Coinbase rely on to guard against theft.
- [16]
The 1-of-2 hybrid path could let wallets move early without waiting for the bitcoin community to decide when legacy signatures should eventually be restricted.
- [17]
Coinbase convened a quantum advisory board in January to study the risks and develop guidance.
- [18]
Coinbase joined a Bitcoin Security Consortium in July alongside BlackRock and Strategy, pledging a combined $15 million toward quantum-proofing Bitcoin.
- [19]
Coinbase highlighted implementation requirements including constant-time verification, reliable cross-platform behavior, predictable signing and resistance to random-number failures.
- [20]
Decrypt described the post as reading less like a mandate than a set of requirements from one of the network's largest stakeholders.
- [21]
A 5% share of supply equals one coin in every 20.
Sources
2 independent publishers whose own reporting we read for this story.
- decrypt.co'It Can Take Years': Coinbase Presses for Bitcoin Quantum Migration to Start Now
1 article · October 14, 2026
- news.bitcoin.comCoinbase Maps Bitcoin’s Quantum Risks While Safeguarding 5% of BTC
1 article · October 14, 2026
Topics and entities
Topics
- Quantum-resistant Bitcoin
- Post-Quantum Cryptography
- Institutional Crypto Custody