Yes, Whonix ™ can be used on USB.
- Select a suitable host operating system,
- install it on USB,
- install a supported virtualizer,
- finally install Whonix ™.
If you are interested in installation of Whonix ™ on USB, see Whonix ™ on USB.
This section on top was edited by Patrick. Original post below. (Removed numbering.)
How to install:
Run Virtualbox and create a new Virtual Machine of linux\Debian type. Do not create any virtualdisks. In the properties of the Machine in the USB section add the USB you want to use for installation and attach also the Debian installation iso image in the Storage section.
Run the machine and installation will start. Install Debian to the USB the same way you install it to HDD. At the end of installation you will be asked if you want to write GRUB to the MBR. Agree to write it to the MBR. After that you will be asked to reboot. You may reboot and then shutdown the newly installed Debian.
Now you may boot your computer from that USB because Debian allows it unlike most other OSes. To do it you should put USB as the primary boot device in BIOS or press a special button at PC start to get to the boot devices selection menu.
After Debian is fully loaded, now you may install Virtualbox to it and import Whonix images into it.
Done. But keep in mind that you will need at least 32 GB USB-stick to implement this guide.
With whonix on USB, you do not leave any traces on your HDDs. Also you may throw the USB out of the window or sink it in the toilet or destroy it in a microwave oven if you have enough time. It will make you feel more secure. The price is slower speed.