Bitcoin and Quantum Computing

The discussion revolves around the strategic approach towards enhancing Bitcoin's security against quantum computing threats, emphasizing a two-phased strategy. The initial focus is on the deployment of post-quantum cryptography (PQC) based scripts as a preliminary step to safeguard transactions. This proposal, however, raises concerns regarding its feasibility and timing as the primary move, given the complexities involved in deciding on the deployment of such PQC mechanisms. Despite the logical appeal of having PQC scripts available early in the process for immediate protection, there are reservations about this approach being the most challenging aspect to agree upon.

An alternative perspective suggests a different initial phase that prioritizes community-driven actions over protocol changes. This involves migrating to non-reused addresses to limit vulnerability to only short-term attacks and advocating for not sharing extended public keys (xpubs), a practice that should be avoided to enhance security. Additionally, the use of script-path Taproot where feasible is recommended, followed by the implementation of some variant of a Cross-DSA Recovery (CDR) protocol, even without a consensus on a specific Post-Quantum Cryptography (PQC) signature scheme. This approach underscores the importance of immediate, practical measures that do not solely rely on the integration of PQC schemes into Bitcoin's protocol.

The broader strategy envisions a gradual, more comprehensive integration of PQC schemes into Bitcoin, acknowledging that achieving consensus on this matter within the Bitcoin community is expected to be a slow process. This expectation stems from the anticipated resistance to change unless the threat posed by quantum computing to Bitcoin becomes undeniably imminent. The discourse illustrates a pragmatic view towards tackling quantum computing threats, advocating for initial steps that strengthen Bitcoin's resilience through community engagement and incremental protocol enhancements while preparing for the eventual inclusion of PQC solutions.