How to protect a database from the Server Administrator in Sql Server

Question

We have a requirement from a client to protect the database our application uses, even from their local administrators (Auditors just gave them that requirement).

In the

Answer 1

another way i heard that a company has implemented but i haven't seen it is: there's a government body which issues kind of timestamped certificate. each db change is sent to async queue and is timestamped with this certificate and is stored off site. this way noone can delete anything without breaking the timestamp chain.

i don't know how exactly this works on a deeper level.