I use a Pi as an air-gapped system for stuff that I really want to be secure. Master keypair was generated on the Pi (which has a hardware RNG in the SoC), and

I use a Pi as an air-gapped system for stuff that I really want to be secure. Master keypair was generated on the Pi (which has a hardware RNG in the SoC), and the only way I get data on/off it is to sneakernet it. The small size of the device makes physical security much easier as well.