As we use Raft storage, workflow is:

1. prepare snapshot
2. encrypt in AES (*)
3. send it to server-side encrypted (*)

(*) Raft storage contains only data encrypted by Vault. As most metadata are already public in rOPS repository, there is no leak of metadata neither.
The only thing is if we do transit operations, as we plan for Eglide Vault, we would store a restorable snapshot containing this transit material. That cascade effect requires more precautions.

We also need a minimal policy to trigger the snapshot and a matching approle.