Aligning privacy incentives in P2MR

The ongoing discussions around Bitcoin's response to potential quantum computing threats highlight significant concerns and strategies within the cryptocurrency's development community. One focal point of the conversation is the low adoption rate of P2TR (Pay-to-Taproot), attributed to the reluctance of wallets and commercial service providers to upgrade their technology stacks unless absolutely necessary. Typically, technological updates in the ecosystem occur when older companies fail and are replaced by newer entities that adopt modern technologies from the start.

The conversation also delves into the broader implications of quantum resistance in cryptocurrency technologies. As apprehensions about quantum computing ("Q-fear") increase, it's anticipated that there will be more compelling incentives, possibly even regulatory pressures, for the adoption of post-quantum cryptography (PQC). This might lead wallet providers to offer an upgrade option to quantum-resistant addresses, which could involve cost implications for users. For instance, transitions to certain quantum-safe outputs like P2MR might come with warnings about increased transaction costs by approximately 15%, whereas upgrades to versions like P2TRv2 could potentially have minimal or no cost impacts.

A critical aspect discussed is the potential impact on Bitcoin if an effective quantum attack occurs before the majority of the network adopts quantum-safe outputs. Such a scenario could leave many users' coins vulnerable, severely damaging trust in Bitcoin in the short term and possibly having long-term destabilizing effects. The alternative—burning a significant amount of users' coins—could be perceived as confiscation, further undermining Bitcoin's value proposition. This perspective is supported by further insights on quantum risk mitigation strategies outlined in a detailed article by Antoine (read more).

In terms of future-proofing Bitcoin against quantum threats, there's a strong advocacy for developing and adopting feature-rich cryptographic schemes that could seamlessly replace current Bitcoin functionalities with lower costs and enhanced security features. Such advancements would ideally support a gradual transition to PQC-only outputs well ahead of any quantum disruptions. This proactive approach emphasizes minimizing transitional challenges while acknowledging that some post-transition chaos might be unavoidable but not necessarily catastrophic.

Overall, the strategic preference leans towards optimizing for pre-quantum threat scenarios while keeping viable pathways open for rapid adjustments post-threat emergence. This involves careful consideration of the specific cryptographic methods employed, such as the potential for narrow EC opcode disabling softforks which could be crucial in a post-quantum context.