read

open suspend override fun read(): String

Retrieves the encryption key from TBS via GET /v1/backup/encrypt-key.

This is used during recovery and eject flows. It sends both the Authorization header (client API key) and the X-Firebase-Token header (Firebase ID token).

On a 401 response, the token is refreshed and the request is retried once.

Return

The encryption key as a string.

Throws

If the token is unavailable or the TBS request fails.