I will be on vacations and where I go, there will be a computer in my room. I don't know what type of computer, how old, what specs, nothing. But probably it will have Windows installed and probably I will only be able to login as restricted user.
Both are things I don't like.
So I thought I could bring my own portable Ubuntu on a bootable 8GB USB stick with me. But you see that 8GB is not really much and USB is also not the fastest thing on the world, especially if the computer might only have 2.0 ports.
Therefore I would love if I could outsource swap and probably even some data or system parts to the HDD of this computer, but I don't want to modify the existing system in any way, so repartitioning is not an option.
I think creating a virtual file system image file inside the existing file system and mounting that one would be best. It should be encrypted though.
And no, a simple live USB is not enough, it has at least to be persistent. However, the HDD using feature should be there too.
So how could I best set this up, a system installed on a USB stick that can create and mount an encrypted virtual disk on an existing file system without irreversibly modifying it? Detailed step-by-step guides appreciated, wherever the installation differs from a normal desktop installation.