Mark Klein, who says he was an AT&T technician for more than 20 years, says that the company aids the National Security Agency in "conducting what amounts to vacuum-cleaner surveillance of all the data crossing the Internet -- whether that be people's e-mail, Web surfing, or any other data," according to a statement Klein released. AT&T has given the NSA extraordinary access to its central switching offices, the nerve centers of its digital networks, Klein contends.
At the NSA's behest, Klein says, the telecom giant constructed a "secret room," off-limits to most of its technicians, that siphoned information from the company's residential Internet service. The secret system also captured information from "peering links," which connect AT&T's infrastructure to other telecommunications networks, potentially giving the NSA access to information traversing "the whole country, as well as the rest of the world."
If true, Klein's allegations provide some of the most detailed and tantalizing peeks at how the NSA eavesdrops inside the United States. (Under the Bush administration's "terrorist surveillance program," the NSA seeks, without court approval, to intercept communications that it believes involve terrorists abroad and their associates in the United States.)
With technical specificity, Klein describes how AT&T constructed, at a San Francisco office, a system of "splitter" cables to divert streams from the main network into the secret room, which he says was built after an NSA agent visited the company. Klein's statement lays out a technically plausible scenario and comports with what individuals familiar with the NSA's domestic operations say the agency is doing -- conducting automated analyses of very large streams of telecom traffic in the hopes of finding telltale signs of terrorist activity.
Klein's claims also add another wrinkle to the evolving NSA story. He says that documents instructing AT&T employees how to connect the peering links to the secret room stated that a sophisticated monitoring device was installed there.
Built by Narus, a company based in Mountain View, Calif., the device, which Klein called a "semantic traffic analyzer," collects large amounts of data that can help reveal a message's origin, destination, and meaning. According to Narus's Web site, government agencies use its products to conduct "lawful intercepts" of electronic communications.
The Narus Web site says that this technology can detect an Internet "traffic anomaly." According to sources knowledgeable about the surveillance program, the NSA looks for unusual or suspicious traffic patterns, such as calls or e-mails emanating from locations known to harbor terrorists and their accomplices, to determine which communications to read or listen to.
Narus sells products to large telecom carriers, including AT&T, according to Steve Bannerman, a company spokesman. Those companies, which have well-established relationships with federal departments and agencies, are valuable conduits for Narus's products. According to government procurement records, AT&T racked up an impressive $304 million in sales to the federal government in fiscal year 2004, with more than 60 percent of that revenue coming from the Defense Department, which oversees the NSA.
An AT&T spokesman declined to discuss Klein's allegations or any work the company might do for the NSA. Klein's written statements were submitted by the Electronic Frontier Foundation, a privacy-rights group, to a federal court as part of the group's lawsuit against AT&T.
That litigation may prompt other telecom carriers and Internet service providers to wonder if they're targets for lawsuits. Telecom executives have told journalists that they have complied with the NSA's requests for access to their networks. One former government official, who is knowledgeable about the NSA's surveillance program, said that AT&T is probably on safe legal ground, particularly if it is acting pursuant to a presidential order.
"For AT&T, [the lawsuit] means nothing," the former official said. AT&T "understands why its operations are important to national security and has always felt that way."