Anyone can rebuild the history. No one can rebuild having predicted it.

Every publish day, the full score state is frozen and sealed with a SHA-256 digest over a canonical serialization. The digest below is the certificate: hash the point-in-time files and compare. Corrections never edit a sealed record; they enter a dated human-resolution lane, and every database update to a grade is captured by an append-only audit trigger. Records sealed before the public launch are backfill and are labelled as such.