Whonix is an open source Linux operating system built around the popular Tor anonymity network software and based on the well known Debian GNU/Linux distribution. It allows users to install a secure, general purpose and anonymous Linux-based operating system that runs entirely in the VirtualBox virtualization software. It is distributed as gateway and workstation editions.
It's distributed as OVA files
The developers doesn’t provide regular ISO images for their Linux distribution. Instead, only OVA (Open Virtualization Format) files are available for download, which can be imported into the VirtualBox application. To import the OVA file, you will need to go to the File menu and select the Import Appliance option. Next, you will be able to browse to the location where you saved the OVA file and import it (the import process will take a long time, because the application needs to create a new disk image).
Provides various attractive features
It is important to know that before you import the OVA file, VirtualBox will ask you to change various settings. Do not change anything on this step, just click the Import button. After importing, you can fire up the Whonix virtual machine as you normally start your other VMs. The system provides various attractive features, such as anonymous IRC, anonymous publishing, and anonymous email through TorBirdy and Mozilla Thunderbird. It allows users to add a proxy behind Tor, torify almost any application, and circumvent censorship.
Supports only the 32-bit architecture
Whonix also supports DNSSEC (Domain Name System Security Extensions) over Tor, encrypted DNS, full IP/DNS protocol leak protection, and transparent proxy. Additionally, user will be able to tunnel Freenet, I2P, JonDonym, Proxy, Retroshare, SSH, UDP and VPN through Tor, as well as to enforce Tor. It supports only the 32-bit (486/686) architecture. The Workstation edition uses the KDE desktop environment and include open source applications like the Iceweasel web browser, XChat IRC, Tor Browser, and many more.