Qubes OS

Privacy Pros: FOSS, no ads or trackers. Provides security through isolation by sandboxing programs and parts of the OS in separate virtual machines. Uses Whonix to integrate with the TOR network to provide anonymity.

Privacy Cons: None

Qubes OS is a security-focused desktop operating system that aims to provide security through isolation. Isolation is provided through the use of virtualization technology. This allows the segmentation of applications into secure virtual machines called qubes. Virtualization services in Qubes OS are provided by the Xen hypervisor.

The runtimes of individual qubes are generally based on a unique system of underlying operating system templates. Templates provide a single, immutable root file system which can be shared by multiple qubes. This approach has two major benefits. First, updates to a given template are automatically “inherited” by all qubes based on it. Second, shared templates can dramatically reduce storage requirements compared to separate VMs with a full operating install per secure domain.

The base installation of Qubes OS provides a number of officially supported templates based on the Fedora and Debian Linux distributions. Alternative community-supported templates include Whonix, Ubuntu, Arch Linux, CentOS, or Gentoo. Users may also create their own templates.

Operating Systems like Qubes OS are referred to in academia as Converged Multi-Level Secure (MLS) Systems. Other proposals of similar systems have surfaced and SecureView and VMware vSphere are commercial competitors.