Against Allowing Quantum Recovery of Bitcoin

The discussion highlights the importance of adapting Bitcoin's protocol to maintain system stability and security without imposing abrupt changes that could provoke adversarial behaviors. The suggestion is made to avoid setting a fixed deadline after which old outputs become invalid, as this could lead to predictable and potentially exploitative rushes by market participants. Instead, a staggered approach to expiration for script types vulnerable to new computational abilities is recommended. This method would phase out weaker security constructions gradually, allowing the network to continue supporting old transactions while discouraging the creation of new ones that are susceptible.

Furthermore, the issue of how to handle coins recovered through advanced quantum methods is addressed. Proposing long timelocks for these coins introduces a special-case rule, which contradicts Bitcoin’s principle of neutral, simple, and general rules. It is advised that the protocol should not differentiate between types of spending but should uniformly apply time-based security measures to all vulnerable outputs. This approach ensures that the intent behind transactions is not judged, maintaining the ethos of "your keys, your coins," provided the keys remain robust.

Lastly, it is emphasized that while the network cannot halt progress in computational or mathematical advances, it can and should encourage users to upgrade their security proactively. By aligning incentives correctly, the protocol can support timely upgrades without resorting to confiscating funds, ensuring both user autonomy and systemic resilience. This strategy allows for a gradual retirement of weaker cryptographic forms, safeguarding the blockchain from becoming a security liability.