Tails is security-focused Debian-based Linux Distribution aimed at preserving privacy and anonymity. The system is designed to be booted as a live DVD or live USB and will leave no digital footprint on the machine unless explicitly told to do so.
A free, open-source, operating system designed to be highly reliable, flexible, and secure. It is based on a tiny microkernel running in kernel mode with the rest of the operating system running as a number of isolated, protected, processes in user mode.