U.S. Intelligence Chief Defends Attempts to Break Tor Anonymity Network

The National Security Agency may have attempted to penetrate and compromise a widely used network designed to protect the anonymity of its users, but it was only because terrorists and criminals use it, too.

That’s the explanation from Director of National Intelligence James Clapper about the recently disclosed attacks by the NSA and its companion agency in the U.K. against The Onion Router, or Tor, a network that uses a constantly changing list of specially configured servers to relay and anonymize the Internet traffic of its users.

In a statement posted to the DNI’s blog, Clapper acknowledged NSA’s “interest in tools used to facilitate anonymous online communication.” However, media coverage of the work fails to point out that “the Intelligence Community’s interest in online anonymity services and other online communication and networking tools is based on the undeniable fact that these are the tools our adversaries use to communicate and coordinate attacks against the United States and our allies.”

And that’s the traffic that the NSA is hoping to capture and analyze. Clapper argues in the post that intelligence agencies are interested only in “… communication related to valid foreign intelligence and counterintelligence purposes.”

New attention has come to Tor and its users in part because of the arrest Wednesday by the FBI of the alleged operator of Silk Road, an online marketplace for the sale and distribution of illicit drugs that existed in the so-called Dark Web, reachable only by a Tor-enabled browser.

In a slide presentation leaked by Edward Snowden, the NSA discussed its struggles to defeat the anonymity that Tor provides. As of the time of the presentation, which is dated June of 2012, it hadn’t had much luck. “We will never be able to de-anonymize all Tor users all of the time,” the presentation says. Using what it calls “manual analysis,” it had had some success in “de-anonymizing” a small fraction of people using Tor. The deck also shows that the NSA sought to collaborate with the Government Communications Headquarters, the United Kingdom’s signals intelligence agency, on its efforts.

It was all legal and appropriate, Clapper argues, because, “Within our lawful mission to collect foreign intelligence to protect the United States, we use every intelligence tool available to understand the intent of our foreign adversaries so that we can disrupt their plans and prevent them from bringing harm to innocent Americans. … Our adversaries have the ability to hide their messages and discussions among those of innocent people around the world. They use the very same social networking sites, encryption tools and other security features that protect our daily online activities.”

The ironic part is that Tor was invented at the U.S. Naval Academy as a project meant to help activists overseas evade surveillance by officials of repressive regimes. A good amount of its funding has come from the NSA’s parent agency, the U.S. Department of Defense.