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

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 changing the network rules and supporting the migration of its ecosystem will take several years. She claims to hold nearly a million BTC, or about 5% of existing bitcoins. His document presents technical avenues, not a plan imposed on the network.

Coinbase focuses on a scalable architecture

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

In its publication of October 13Coinbase particularly highlights P2MR, presented in the BIP-360as well as P2TRv2. The first eliminates Taproot’s per-key spend path, to better protect funds against attacks targeting public keys exposed over long periods of time.

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

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

Why Bitcoin must anticipate quantum risk

For Coinbase, the 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 therefore risk leaving too little time to act. This deadline is already debated in the industry.

Several dates reinforce this urgency: the United States plans to impose post-quantum standards as early as 2030, while browsers and operating systems could follow in 2033. Furthermore, the American 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 from 2028. Bitcoin will, however, need to obtain the agreement of its participants, since no central authority can alone impose an evolution of the protocol.

Up to 6.9 million BTC potentially exposed

The other difficulty concerns bitcoins whose public keys are already visible. According to the Coinbase Quantum Advisory, up to 6.9 million BTC would be affected, including 1.7 million associated with legacy P2PK releases. During October 14, this amount represents approximately $563 billion.

For its part, Glassnode identified more than six million BTC exposed, or 31.2% of the supply. These estimates vary depending on the calculation methods and categories of bitcoins used.

Finally, lost or inactive coins, particularly those associated with the Satoshi era, raise a delicate question: how to protect them without creating new risks? Coinbase believes that any fallback solution will also need to be resistant to quantum attacks.

Developers must now decide between the size of signatures, the space available in blocks and the choice of algorithms. Until a migration occurs, each private key associated with 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.