For perfect security, the biggest problem is that you can't buy any hardware and can't use any third-party software because it could be malicious (and can't hir

For perfect security, the biggest problem is that you can't buy any hardware and can't use any third-party software because it could be malicious (and can't hire/delegate anything). To serve anything via HTTPS you pretty much need a general purpose computer, which is going to be very challenging to build by hand from scratch starting from raw materials.