When NSA whistle-blower Edward Snowden first emailed Glenn Greenwald, he insisted on using email encryption software called PGP for all communications. But this month, we learned that Snowden used another technology to keep his communications out of the NSA’s prying eyes. It’s called Tails. And naturally, nobody knows exactly who created it.

Tails is a kind of computer-in-a-box. You install it on a DVD or USB drive, boot up the computer from the drive and, voila, you’re pretty close to anonymous on the internet. At its heart, Tails is a version of the Linux operating system optimized for anonymity. It comes with several privacy and encryption tools, most notably Tor, an application that anonymizes a user’s internet traffic by routing it through a network of computers run by volunteers around the world.

Read more at Wired.