Public key recovery for EC leaves in P2MR (BIP-360)

The email discusses the merits and potential drawbacks of using P2QR as a security option in blockchain technology. P2QR is recognized for providing security even when common practices, such as address reuse and public key sharing, are prevalent within certain workflows. This protocol offers an inherent security advantage by not allowing elliptic curve (EC) spending from its inception, thus eliminating risks associated with EC public key exposure. However, this stringent security measure comes at a significant cost and may not appeal to all users, making its widespread adoption questionable unless there is a substantial imminent threat from quantum computing.

Furthermore, the discussion highlights the comparative benefits of another protocol, P2MR, which retains an EC spending path. This feature could be crucial if a critical flaw is discovered in the chosen post-quantum cryptography (PQC) algorithm before EC spending is phased out, allowing for a migration to safer alternatives. The sender expresses skepticism about the rapid adoption of P2QR, citing the lack of significant cost incentives compared to traditional address types and the potential delay in recognizing quantum threats until it might be too late for effective mitigation.

Lastly, while the elimination of on-chain EC public key exposure is emphasized as paramount, the sender notes that other forms of exposure, such as through extended public keys used in hardware wallets and auditing, pose less risk but are nonetheless challenging to completely secure. The overall sentiment suggests a cautious approach to the adoption of P2QR, advocating for a balance between advanced security measures and practical implementation costs, ensuring that transitions can occur smoothly without undue financial burden prior to the arrival of quantum computing threats.