Coinbase Says Bitcoin’s Post-Quantum Transition Will Take Years

Coinbase wants to prepare Bitcoin for the arrival of quantum computers without waiting for them to become a concrete threat. In a publication dated October 13, the platform emphasizes that modifying the network rules and supporting the migration of its ecosystem will take several years. It claims to hold nearly one million BTC, about 5% of existing bitcoins. Its document presents technical avenues, not a plan imposed on the network.

Coinbase bets on an evolving architecture

Coinbase does not simply recommend replacing current signatures. The platform rather wants to create an architecture capable of hosting different post-quantum protection mechanisms without disrupting the network. This approach makes all the more sense as an open competition reduced the cost of a quantum-resistant transaction from $320 to $67 in September.

In its October 13 publication, Coinbase notably highlights P2MR, introduced in the BIP-360, as well as P2TRv2. The first removes the Taproot key spending path to better protect funds against attacks targeting public keys exposed for long periods.

At the same time, the platform proposes a hybrid mechanism allowing the same bitcoins to be spent with a classic key or a post-quantum key. This solution would ease the transition between the two systems.

Regarding algorithms, Coinbase cites ML-DSA, SLH-DSA, FN-DSA, and SHRINCS. It also favors a stateless solution, considered more suitable to the network’s security needs. Finally, new mechanisms must remain compatible with MPC systems and hardware security modules (HSM) used by custodians.

Why Bitcoin must anticipate the quantum risk

For Coinbase, timing is the main argument. ” Consensus changes and ecosystem migrations can take years“. Waiting for the famous Q-Day, the moment when a quantum computer could break current cryptographic signatures, would risk leaving too little time to act. This deadline is already debated in the industry.

Several dates heighten this urgency: the United States plans to impose post-quantum standards by 2030, while browsers and operating systems could follow in 2033. Moreover, the U.S. federal government plans to abandon elliptic curve cryptography after 2035.

At the same time, the United States has committed up to $215 million to demonstrate machines capable of operating with hundreds of logical qubits by 2028. Bitcoin will still need to get approval from its participants, as no central authority can impose a protocol evolution alone.

Up to 6.9 million BTC potentially exposed

The other difficulty concerns bitcoins whose public keys are already visible. According to Coinbase’s quantum council, up to 6.9 million BTC could be concerned, including 1.7 million linked to old P2PK outputs. As of October 14, this amount represents about $563 billion.

Meanwhile, Glassnode counted more than six million BTC exposed, i.e. 31.2% of the supply. These estimates vary depending on calculation methods and categories of bitcoins considered.

Finally, lost or inactive coins, especially those from Satoshi’s era, raise a tricky question: how to protect them without creating new risks? Coinbase believes any fallback solution must also withstand quantum attacks.

Developers must now decide between signature size, available block space, and algorithm choice. While awaiting a migration, every private key linked to an exposed public key remains a potential risk. For Coinbase, it is better to start preparing Bitcoin today than to have to act urgently tomorrow.