He was an unlikely hero. For more than 22 years, Klein worked for AT&T. He started with the company as a Communications Technician in New York, where he remained from November 1981 until March 1991. He later continued in that capacity in California until 1998. From January 1998 to October 2003, Klein worked as a Computer Network Associate in San Francisco. Starting in October 2003, he returned to the role of Communications Technician, after which he retired in May 2004.
In 2006, after reading reports that the NSA was hoovering up American internet traffic, he realised he had firsthand knowledge—and evidence—of how it was happening.
In January 2003, he toured the AT&T central office on Folsom Street in San Francisco—three floors of an SBC building. There, he saw a new room being built adjacent to the 4ESS switch room, where the public’s phone calls are routed. He discovered that the person whom the NSA interviewed for a secret job was the person working to install equipment in this room. The regular technician workforce was not allowed in the room.
In San Francisco, the “secret room” is Room 641A at 611 Folsom Street, the site of a large SBC phone building, three floors of which are occupied by AT&T. High-speed fibre optic circuits come in on the 8th floor and run down to the 7th floor where they connect to routers for AT&T’s WorldNet service, part of the latter’s vital “Common Backbone.”
To snoop on these circuits, a unique cabinet was installed and cabled to the “secret room” on the 6th floor to monitor the information going through the circuits. (The cabinet's location code is 070177.04, which denotes the 7th floor, aisle 177, and bay 04.) The “secret room” itself was roughly 24-by-48 feet, containing perhaps a dozen cabinets, including equipment such as Sun servers, two Juniper routers, plus an industrial-size air conditioner.
While doing his job, Klein learned that fibre optic cables from the secret room were tapping into the WorldNet circuits by splitting off a portion of the light signal.
“I saw this in a design document, entitled “Study Group 3, LGX/Splitter Wiring, San Francisco” dated Dec. 10, 2002. I also saw design documents dated Jan. 13, 2004 and Jan. 24, 2003, which instructed technicians on connecting some of the already in-service circuits to the “splitter” cabinet, which diverts some of the light signal to the secret room. The circuits listed were the Peering Links, which connect Worldnet with other networks and hence the whole country, as well as the rest of the world,” he said.
Rather than keeping his head down, he walked into the offices of the Electronic Frontier Foundation (EFF) and asked, “Do you folks care about privacy?”
Klein had more than just stories—he had over a hundred pages of AT&T’s internal schematics and documentation proving the mass spying operation. At that point he was retired and did not care about losing his job.
Despite threats from AT&T, Klein refused to back down. His evidence became the foundation for two major lawsuits against the NSA’s warrantless surveillance, Hepting v. AT&T and Jewel v. NSA.
He even marched into Washington to demand accountability, earning recognition from Senator Chris Dodd as a true American hero.
Klein’s fight was ultimately stonewalled by a Congress and judicial system too timid to take on the government. Even after Edward Snowden’s 2013 leaks confirmed and expanded on Klein’s revelations, the mass spying apparatus remains largely intact.
On the EFF’s blog in a tribute to Klein the freedom of speech group said that his “bravery lit a fire under the fight for digital privacy.”
“ His legacy is a reminder that standing up to Big Brother takes guts—and that the battle for privacy is far from over. Section 702, the legal fig leaf covering the NSA’s ongoing data dragnet, is set to expire in 2026, and organisations like EFF are still fighting to put an end to mass surveillance once and for all,” the EFF said.