Coinbase, which holds about 5 percent of all bitcoin in existence for its clients — including banks, asset managers and hedge funds — is urging Bitcoin developers to start preparing now for the long-term threat of quantum computing. In a blog post published October 13 and outlined by Coinbase's Shashank Agrawal, the exchange laid out technical considerations for Bitcoin's transition to post-quantum security, arguing that the upgrade path could take years and should begin before powerful quantum computers become a real threat. The core concern: a sufficiently advanced quantum computer could eventually derive private keys from public keys and drain vulnerable wallets. For an industry built on the safety of holding Bitcoin, the quantum question is the ultimate long-tail risk.

Coinbase's recommendations center on flexibility and staged adoption. The exchange favors post-quantum signature schemes that can be deployed without making transactions dramatically more expensive or complicated, reliable implementations that protect both everyday users and large institutional holdings, and support for multiparty security systems used by custodians. Rather than proposing a single final upgrade, Coinbase wants developers to examine different approaches now — treating quantum readiness as a research priority rather than an emergency patch.

The most contentious issue is what to do about dormant or late-migrating wallets — the millions of coins in addresses whose owners may never move them. Coinbase argues this question should be addressed separately so it does not delay broader protections for active users. That framing matters: tying the fate of lost coins to the security upgrade for everyone else could stall the entire effort in governance debates that Bitcoin is famous for.

The timeline is the real message. Some projections suggest a cryptographically relevant quantum computer, though it does not exist today, could arrive within a few years. Bitcoin's upgrade history shows that even uncontroversial changes take years to deploy across the network's decentralized node operators. Starting the conversation now is less about imminent danger and more about matching the upgrade cycle to the threat horizon.

## Why Coinbase is speaking up

As the custodian of roughly one in twenty bitcoins, Coinbase has more at stake in Bitcoin's long-term security than almost any other company. Its clients — the banks and asset managers now holding Bitcoin ETF shares as collateral — need assurance that the asset's cryptography will survive the next decade of computing advances. The post is also a signal to regulators and institutions that the industry is thinking seriously about tail risks. Whether Bitcoin's famously conservative developer culture acts on the warning is another question — but understanding how Bitcoin ownership works now includes understanding what could one day threaten it.