LeoWandersleb on Nostr: Q-Day rescue for P2TR or otherwise exposed pubkeys from HD-wallets: Attacker has your ...

Q-Day rescue for P2TR or otherwise exposed pubkeys from HD-wallets:

Attacker has your private key (via QC), but they lack the BIP32 lineage. Child keys are derived by hashing a Parent xPub. Proposal: Soft-fork to require revealing that Parent xPub to spend. This proves you generated the key via the seed. QC attacks the curve, not the hash derivation.

Of course, revealing Parent xPub + Broken Child Key mathematically leaks the Parent Private Key. You must sweep the entire account at that point.