the computer reads the encrypted message from this paper tape (5 bit ASCII)
this machine did the decryption once the other machine had output the decryption parameters
they have a whole collection of tubes (pre-transistors) to replace the ones that break on their machines
impressive they had so many of those machines, still working
and this too (Asmtrad CPC464+memory upgrade+floppy)
didn't have this one at home, but worked with them at SGI
those I never had, but I wish I did. Archimedes was awesome and way ahead of its time with Arm RISC CPUs