FROST solves a different problem. It keeps a hot key safe by splitting it across participants.

Cold Root solves the opposite problem. The root key never touches any online device at all.

You create the key you actually use by doing it offline:

- Use the cold root to deterministically derive a new epoch key.

- Export only the epoch key and a signed lineage proof.

- The root never leaves cold storage.

The client only ever sees the hot epoch key. All continuity comes from the signature the root made offline.