It is a complete operating system designed to be used from a DVD, USB stick, or SD card independently of the computer’s original operating system. It is Free Software and based on Debian GNU/Linux. Tails comes with several built-in applications pre-configured with security in mind: web browser, instant messaging client, email client, office suite, image and sound editor, etc.
Is a live operating system, that you can start on almost any computer from a DVD, USB stick, or SD card.
It aims at preserving your privacy and anonymity, and helps you to:
use the Internet anonymously and circumvent censorship;
all connections to the Internet are forced to go through the Tor network;
leave no trace on the computer you are using unless you ask it explicitly;
use state-of-the-art cryptographic tools to encrypt your files, emails and instant messaging.