Bitcoin Quantum Defence Advances, With Caveats

As I've previously noted, a quantum attacker who cracks your private key still can't reconstruct the seed phrase it was derived from. Proving you know that parent key — without revealing it — is something only the real owner can do.

However Satoshi's 1.1 million BTC were created the old way — raw keys, no master seed, no derivation path. The new tool has nothing to grip. Those coins remain the clearest quantum target on the network, and nothing about this announcement changes that.

So we are clear the proposal would be something like:

→ provide a migration window for Bitcoin owners to voluntarily move funds to quantum resistant addresses

→ freeze funds that miss the window

→ provide a "recovery tool" that enables those funds to be un-frozen by proving you have the parent key (seed phrase), without exposing your parent key. The owner constructs and broadcasts the "unfreeze" transaction with the proof attached; the network validates it, and the funds find a home in a new quantum resistant address.

→ a quantum hacker may hack the private keys (derived from public keys) of non-quantum resistant addresses in the future but because those funds are frozen and they cannot derive the seed phrase that vector of attack is redundant.

The caveats:

→ the prototype is unaudited and incomplete.

→ it is also in the stage of having proved it is feasible.

→ perhaps the biggest caveat, pre-BIP32 coins like Satoshi's, freeze-plus-recovery collapses back to freeze-only. Those coins are effectively burned.

Project Eleven's prototype covers recovery. However its relevance depends on a separate freeze proposal, BIP-361 happening. The freeze is the key sticking point as many see any freeze of coins (recovery or not) as confiscation and fundamentally unacceptable for Bitcoin.

We are still a long way away from a solution.