NSA tried to develop attacks against people using Tor online anonymity tool

Top secret documents, disclosed by whistleblower Edward Snowden reveal that the US National Security Agency had made repeated attempts to develop attacks against people using Tor, a popular tool designed to protect online anonymity, which comes as an ironic twist as the software was primarily funded and promoted by the US government itself.

According to the documents, the agency's current successes against Tor, relied on identifying users and then attacking vulnerable software on their computers.

A technique developed by the agency targeted the Firefox web browser used with Tor, to gain full control over targets' computers, which included access to files, all keystrokes and all online activity.

However, according to the documents, the fundamental security of the Tor service remained intact.

A top-secret presentation, titled 'Tor Stinks', stated: "We will never be able to de-anonymize all Tor users all the time." It continued: "With manual analysis we can de-anonymize a very small fraction of Tor users," and said the agency had had "no success de-anonymizing a user in response" to a specific request.

Another top-secret presentation called Tor "the king of high-secure, low-latency internet anonymity".

The Onion Router (Tor), an open-source public project bounces its users' internet traffic through several other computers, which it called "relays" or "nodes", to keep it anonymous and avoid online censorship tools.

Tor was first developed by the US Naval Research Laboratory, more than a decade ago as a tool to allow anonymous communications and web browsing.

Later it was quickly embraced by privacy advocates, including the Electronic Frontier Foundation and continues to receive substantial federal funding. The maintenance of Tor is now coordinated by non-profit group, the Tor Project.

Political activists worldwide are trained by the state department on the use of Tor to protect communications from the intelligence services of repressive governments.

The anonymity service also has gained popularity with criminals - especially dealers of illicit drugs, military-grade weapons and child pornography - and terrorists looking to evaded tracking by intelligence services.

According to documents provided by Snowden, an NSA technique code-named egotisticalgiraffe was able to unmask 24 Tor users in a single weekend.

The operation also allowed the NSA to identify a key propagandist for al-Qaeda in the Arabian Peninsula, as the group's offshoot in Yemen is known, after he posted information and instructions on the group's web site.