If you haven't heard of it, Tor is free software that anyone can install on their computer, which gives them almost total online anonymity and privacy.
When using the Internet, Tor users are randomly directed through a worldwide network of thousands of servers, which makes it very difficult for a third party, such as the National Security Agency (NSA), to learn your location and browsing habits. Tor works with web browsers, instant messaging and other types of software.
Tor is used by hundreds of thousands of people, such as journalists, lawyers and human rights activists in repressive countries.
According to secret NSA documents published by The Guardian in October of 2013, the NSA called Tor "the King of high secure, low latency Internet anonymity" with "no contenders for the throne in waiting."
The NSA is so concerned about Tor that it labels people who simply go to the Tor website TorProject.org as potential "extremists," reports the German website Tagesschau.
The German report is based on an analysis of the source code used in XKeyscore, the NSA’s main electronic surveillance program, notes RT.com.
XKeyscore also monitors web searches for other encryption software such as Tails.