Changes to BIP-360 - Pay to Quantum Resistant Hash (P2QRH)

The discussion revolves around the development and naming of a new proposal aimed at enhancing Bitcoin's resistance to potential quantum computer attacks. The primary motivation behind this initiative is the looming threat that quantum computing poses, rather than its utility for other purposes. A suggested name for this proposal, P2QRTLRH (pay-to-quantum-resistant-tapleaf-root-hash), is considered too lengthy by some, highlighting concerns about the time spent on deciding a name before the proposal is even accepted into the Bitcoin Improvement Proposals (BIPs) repository. This scenario underscores the importance of reaching a consensus on terminology without getting bogged down in minor details.

The dialogue further acknowledges the quantum resistance of SHA256, emphasizing the significant risk to Bitcoin if SHA256 pre-image security were compromised. It touches upon the concerns of senders regarding the safety of their transactions prior to receipt by the intended party, indicating a preference for making address types distinguishable to facilitate user verification against long-exposure attacks. This approach mirrors the existing practice of using specific prefixes to identify segwit addresses on the mainnet, suggesting that such transparency is valued within the community.

The conversation also considers the practical aspects of implementing new features within the Bitcoin protocol, particularly in relation to user behavior and wallet updates. The slow pace at which wallets adopt new standards and the use of physical backups like steel wallets pose challenges to ensuring widespread adoption of any new output type designed to counteract quantum threats. The argument is made for choosing solutions that minimize user error, recognizing the difficulty in quantifying the likelihood of such errors occurring. The future compatibility of any added opcodes with P2QRH is noted, alongside a question regarding the necessity and timing of introducing a new output type specifically for quantum resistance.

Finally, the exchange questions the rationale behind explicitly labeling new opcodes as "quantum-resistant" and seeks clarification on the specific use cases envisioned by proponents of this approach. The potential benefits, such as transaction size reduction offered by P2QRH compared to traditional methods when not under quantum attack, are acknowledged yet questioned in terms of practical application. This inquiry highlights the broader debate over prioritizing developments that directly address quantum vulnerabilities within the Bitcoin protocol.