> For my Tarsnap online backup service I compile and cryptographically sign the packages on a system which has never been connected to the Internet. Before I tu

> For my Tarsnap online backup service I compile and cryptographically sign the packages on a system which has never been connected to the Internet. Before I turned it on for the first time, I opened up the case and pulled out the wifi card; and I copy files on and off the system on a USB stick. How can you be sure the system you copied those files from is not compromised, the micro-controller on the USB stick has not been compromised, and now it's not going to take control of the build system and replace the compiler chain with a modified one which will make all your software vulnerable?