I'm gonna dive into those later, thank you. The way I see it, sensitive information should be offline. But you often need to access it in an automated manner.

I'm gonna dive into those later, thank you. The way I see it, sensitive information should be offline. But you often need to access it in an automated manner. So set up a secure interface. Secure means that the protocol is minimalistic and you are monitoring unusual access patterns. E.g. serial interface with the sensitive data computer, where you only ask for X and it provides you X. Almost never you need to fetch all data at once. So you can set up some hourly limits or whatever. You can use microcontroller to validate data transmission. You can set up a hardware button if necessary. The beauty of it, is that the sensitive box could be running windows 3.11. The attack surface as minimal as it can be. When you have it on a computer that's connected to the Internet, in my eyes you already lost the game. I'm quite convinced it looks the same in the eyes of some 3 letter agencies, and it sure gets an average script kiddie excited.