The scale at which the National Security Agency surveilled and swept through millions of phone and internet records could be larger than before thought by groups like the ACLU. Research by two Stanford graduate students estimated that scale could be larger.
The Foreign Intelligence Security Court’s allows the NSA to collect phone numbers within three degrees of separation (three hops) from a specific target’s phone number. Slate describes a “hop” as being “the communications of the person it’s targeting, plus the communications of that person’s contacts.” Based on the “three hops” rule, it has been estimated that one phone with 40 contacts can yield 2.5 million individual phone records. Slides released via Edward Snowden indicate that the NSA might have up to 117,000 active targets.
The students that performed the study, Jonathan Mayer and Patrick Mutchler, think that number could be even greater, though. They assert that the NSA’s network may be more expansive than the simple “three hops” measure. Instead, Mayer and Mutchler believe that phone numbers are connected to more than what’s in someone’s contact list.
Using T-Mobile as an example, whose customers are connected a central voicemail number, they estimated that by two hops, 17.5 percent of T-Mobile subscribers were connected by the voicemail number.
“That’s potentially tens of millions of Americans connected by just two phone hops, solely because of how their carrier happens to configure voicemail,” they said.
Voicemail numbers are just one way the NSA gathers phone records, they assert. In addition to voicemail, Mayer and Mutchler say that through “spam robocalls and calling services like Skype, many of us are connected by just a small set of phone numbers.”