PQC output type discussion

The discussion on integrating new output types in Bitcoin's protocol, specifically P2TRv2 and CISA, highlights several critical aspects and divergent views regarding their implementation and potential impact. It is clear that both technologies aim to address different user bases and risk profiles, which could complicate their combined adoption. P2TRv2 is mainly targeting wallets and service providers not primarily focused on the earliest adoption of cutting-edge technologies like CISA. These groups are more likely to continue using distinguishable output types for an extended period, potentially indefinitely. The debate extends to the effectiveness of combining these technologies into a single output type to minimize the footprint and simplify the user experience.

The introduction of fee savings, although modest at approximately 5%, may not significantly influence wallet developers' decisions to adopt new output types, as evidenced by examples from exchanges where the savings become more substantial (~5% off). Nonetheless, it is essential to note that such transitions might occur independently of CISA due to the intrinsic benefits of P2TRv2, particularly in enhancing security against potential CRQC risks.

Furthermore, the strategic deployment of technologies like Tripwire and EC disabling pose additional complexities. The concept of 'Tripwire without miner lockdown' is seen as a psychological tool rather than a robust technical solution to enforce collective reliance on eventual EC disabling. This strategy is underscored by concerns over prematurely disabling EC, which could deter stakeholders due to lack of incentives and disrupt the migration process. The consensus seems to lean towards separating the deployments of risk mitigation measures (P2TRv2 + Tripwire) and full migration strategies (P2MR + eventual EC disabling + Witness style), prioritizing them based on the evolving landscape of quantum computing and the realization of CRQC threats.

In summary, the integration of new technologies in Bitcoin's protocol, such as P2TRv2 and CISA, requires careful consideration of user adoption patterns, cost implications, and technological readiness. The phased deployment strategy, emphasizing risk mitigation before full migration, appears to be a prudent approach to navigating the uncertainties associated with future technological advancements and security threats.