> Iran learned this the hard way - their centrifuges were isolated from the internet, but someone managed to get access to the memory sticks used to transfer d

> Iran learned this the hard way - their centrifuges were isolated from the internet, but someone managed to get access to the memory sticks used to transfer data in and out It's not a sufficient answer in itself, but it's a good response. It's a lot harder to compromise a physical system than to compromise a network. Furthermore, it's a lot harder to compromise a physical system and go undetected than to compromise a network. Both are possible, but given an offline system with good physical security and an online system with good physical security, you're still better off with the offline version.