Aligning privacy incentives in P2MR

The discussion centered on the strategic development of new Bitcoin address types designed to be secure against quantum computing threats, while also maintaining efficiency for transactions that occur before the advent of quantum decryption capabilities, referred to as Q-day. The proposed addresses would function in a dual capacity: allowing quantum-vulnerable spending paths initially, which would later switch to quantum-secure methods as Q-day approaches. This transition could follow various strategies, including a gradual shift where quantum-vulnerable paths are disabled in a controlled manner (Later-dominant), an emergency fallback where users independently secure their paths due to unforeseen acceleration towards Q-day (Self-reliance), or a more drastic approach involving a hard fork to implement zero-knowledge proofs for transaction verification if other methods fail (Disaster-recovery).

Each scenario reflects different anticipations about the readiness and response of the Bitcoin community to quantum threats. The Later-dominant strategy assumes a structured transition, while the Self-reliance path places responsibility on individual users to maintain secrecy around their quantum-vulnerable public keys. The Disaster-recovery approach contemplates a hard fork—a divisive and radical change that would only become necessary if other strategies do not adequately secure the network before Q-day.

The discussion also highlights concerns regarding the implementation timelines and practical challenges associated with these strategies. For instance, enabling post-quantum opcodes might offer security but could come at the cost of increased transaction fees or reduced block capacity. There's skepticism about the widespread adoption of new protocols like P2TRv2, especially if traditional spend paths remain cheaper until Q-day. The debate touches upon the balance between technological preparedness and user behavior, noting that only a fraction of users might adopt advanced security measures voluntarily.

Furthermore, external factors such as state-of-the-art physics research, covert government activities, and general user carelessness were considered as variables that could influence the effectiveness of any planned changes. The conversation underscores the complexity of predicting Q-day and preparing for it, emphasizing the need for a robust, adaptable strategy that accommodates various outcomes and minimizes potential disruptions to the Bitcoin ecosystem.