Both seem to use a “signed rotation” approach. Algorand keeps your public key stable while adding metadata that your spend key has changed and links the two. Atproto similarly uses the recovery key to sign a rotation op which can regenerate your signing key, additionally readjusting the tree to preattack state (by setting prev of the rotation to the last precompromise state).

https://news.ycombinator.com/item?id=33747383