AIP-22: dated correction to the transition principle (from stage 5 one post-quantum validator key can serve a non-validating node a branch up to the next anchor, which a quorum certificate ends)

aips/AIP-22.md

@@ -97,6 +97,8 @@ Measured constants used throughout, with source:
 
 **The transition principle.** ECDSA is not removed from the wire in one step. It is first demoted from a validity criterion to a compatibility envelope (section 4), then removed from the header (section 5). At no activation height does a node accept a block on ECDSA alone that it would have refused before; every step only tightens what a syncing node requires.
 
+**Correction added 2026-10-26 (to the last sentence of the paragraph above, and to "Every step here tightens what a syncing node requires" under Rationale).** It holds against an adversary with classical keys, who from stage 5 can produce no header a node admits, and does not hold against one leaked or misused post-quantum validator key: below stage 5 a node that does not take part in consensus admitted a header between anchors only on the ECDSA committed seals of a quorum, and from stage 5 it admits it on the Falcon-512 seal of its proposer alone (section 5), so one such key can serve that node a branch up to the block before the next anchor, which ends it for a node that requires the seals of a quorum in its certificate.
+
 ### 2. Per-block proof: the options, with cost, and the choice
 
 Costs are the post-quantum overhead per block, over the ECDSA baseline that remains until section 5, as in the sizing study. "All N" attaches every heard seal (K is a floor: measured 8 to 9 of 9 attached at N = 9, cap 9 today per the findings register of 2026-09-11); "Q only" caps the proposer at the quorum.