Qubes OS is a new Operating System, like Tails, that is dedicated to
computer security. Qubes’ design is based off an important law of software:
all programs contain bugs. Short of never connecting your computer to the
internet, the best way to stay secure is to minimize the damage caused
when you do eventually get hacked and “sandbox” the most vulnerable
programs away from the rest of your computer.
Qubes uses virtual machines to let you manage separate “security domains”.
A virtual machine (VM) is basically a tiny operating system running inside
of your real operating system. If your VM gets hacked, the attacker is able
to access the files and read keystrokes in that VM, but not in other VMs or
on your host computer. In Qubes all software (besides the desktop environment)
is running inside of VMs, and you can easily and efficiently make as many as
you need for whatever purposes you need. It's also designed in such a way
that if one VM gets infected with malware, the malware won't be there the
next time you reboot that VM. Qubes takes an appraoch called security by
compartmentalization. This approach allows you to keep the different things
you do on your computer securely separated from each other in isolated VMs
so that one VM getting compromised won’t affect the others. In this way,
Qubes allows you to do everything on the same physical computer without
having to worry about a single successful cyber attack taking down your
entire computer in one fell swoop.