More secret National Security Agency documents leaked by Edward Snowden to The Guardian suggest that the U.S. agency's British counterpart intercepts petabytes worth of communication data daily from fiber-optic cables.
The operation codenamed "Tempora" by Britain's Government Communications Headquarters (GCHQ) has been going on for at least 18 months and involves the use of "intercept probes" attached directly to transatlantic fiber-optic cables landing on British shores from telephone exchanges and Internet servers in North America.
Commercial companies, described in the documents only as "intercept partners," were secretly used to attach the intercepts on behalf of the GCHQ. The companies, whose identities have been concealed in the documents, were apparently obliged by law to cooperate with the GCHQ and in some cases paid for their effort.
The intercepts have allowed GCHQ to scoop up and filter huge volumes of data, including email content, records of phone calls, Facebook entries and Internet browsing histories. "For the 2 billion users of the world wide web, Tempora represents a window on to their everyday lives, sucking up every form of communication from the fiber-optic cables that ring the world," the Guardian noted.
As of May a year ago, 300 analysts from the GCHQ and 250 from the NSA had been assigned to sift through and analyze the data for terrorist threats and signs of other criminal activity.
Each set of analysts, however, was operating under different rules, with those at the NSA appearing to have more stringent guidelines about how they use the data.
Details of the GCHQ operation are likely to fuel new fears about the nature and scope of the data surveillance activities by the NSA. The concerns first surfaced when Snowden leaked two documents describing a couple of surveillance programs to the Guardian and the Washington Post. Since then, there have been several other disclosures pertaining to surveillance activities by the NSA and the FBI and the authority under which it is being done.
The Obama Administration and U.S. intelligence agencies have insisted that everything is being done under proper authority and oversight. They have downplayed concerns about U.S. persons being illegally spied on and have maintained that the surveillance activities are crucial to national security.
Even so, the sheer scale of the efforts, at least as described by the documents that the Guardian claims to have obtained from Snowden, is sure to heighten calls for more transparency into the data collection programs.
According to the Guardian, the GHCQ has been expanding its data interception capabilities steadily over the past five years. As of last year, the agency was capable of handling 600 million telephone "events" a day and was able to process data from at least 46 of the more than 200, 10Gbps fiber-optic cables on which it placed intercepts.
The agency applies a series of filters to the data it intercepts to reduce the volumes. For instance, the first filter throws out all high-volume, low-value traffic such as peer-to-peer downloads, reducing traffic volumes by up to 30% right away, the paper noted.
Numerous other filters pull out information that is of specific interest to the NSA or GCHQ. The NSA uses a total of 31,000 specific search terms, including specific phone numbers, email addresses and other identifiers to keep an eye on communications being carried out by persons or entities of interest. The GCHQ uses about 40,000 such terms to filter the information it intercepts.
The technology allows GCHQ to store certain information of interest for up to three days and phone call metadata for up to 30 days. Such data interception and filtering has apparently allowed the agency to identify potential terrorist threats, child exploitation networks and cyber threats.
This article, British intelligence tapping fiber-optic cables for massive amounts of data, was originally published at Computerworld.com.
Jaikumar Vijayan covers data security and privacy issues, financial services security and e-voting for Computerworld. Follow Jaikumar on Twitter at @jaivijayan or subscribe to Jaikumar's RSS feed. His e-mail address is firstname.lastname@example.org.
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This story, "British intelligence tapping fiber-optic cables for massive amounts of data" was originally published by Computerworld.