Imagine, for a moment, that you have a process (as in procedure, not as in "running program").
This process involves downloading an archive file, decrypting it, unpacking it, converting the files inside from one format to another, and printing them. After printing, the resulting prints must be proofread and checked for errors, and if errors are found, the file must be reprinted (possibly reprocessed then reprinted - depends on the kind of error).
Added difficulty #1: As soon as you download the file the remote server deletes it. You cannot affect this behaviour. The file you downloaded in the first step is the only copy you get.
Added difficulty #2: Commercially available software only. No writing a custom app that does all this in one step.
The problem: At no point may any of the files in this process be saved unencrypted to disk, ever. Saving them encrypted is heavily frowned upon but could potentially be acceptable.
I'm looking for solutions.
Obvious solution #1: RAM drive. Have the OS treat a hunk of RAM as really fast disk, save the files and do all the processing there.
Obvious solution #2: Encrypted folder. Each user (oh, did I mention multiple users?) has a passphrase to open it, nothing is stored outside it.
Obvious solution #3: Virtual machine. All storage and processing is done on a VM, which trashes itself without writing "to disk" when closed.
Any other ideas? Anything you'd prioritise trying?