"Yoy G0" <yoyg0@hod.aarg.net> wrote in message

Put the machine in a large safe. The larger the better
to prevent anyone from substituting a replica safe.
No outside connections of any kind allowed.
The best arrangement would likely be a laptop.

Should you decide to put just a floppy disk into the machine,
then that would be the equivalent of an outside connection
and it could, at least in theory, compromise the system.

Now you just have to worry about securely charging the battery.

Note that you'll have to destroy at least the hard drive
should you decide to remove the laptop from the safe.
I'd suggest destroying the whole machine just in case
anything extra was installed before it went into the safe.

In the end, this would only be as secure as the safe it was in.
Still not 100% security, but fairly close.

100% protection can be pretty difficult to work with.