[Pete Yost for the Boston Globe][1]:
> For the first time, NSA Deputy Director John C. Inglis disclosed that the agency sometimes conducts what is known as three-hop analysis. That means the government can look at the phone data of a suspected terrorist, plus the data of all of the contacts, then all of those people’s contacts, and all of those people’s contacts.
> If the average person calls 40 unique people, three-hop analysis could allow the government to mine the records of 2.5 million Americans when investigating one suspected terrorist.
I was [looking for these numbers][2] a while back, and I finally found the article I was thinking of.
[Here’s Sean Gallagher for Ars Technica][3]:
> The Internet has blown the level of interconnectedness though the proverbial roof—we now have e-mail, social media, and instant message interactions with people we’ll never meet in real life and in places we’ll never go. A 2007[ study][4] by Carnegie Mellon University machine learning researcher Jure Leskovec and Microsoft Research’s Eric Horvitz found that the average number of hops between any two arbitrary Microsoft Messenger users, based on interaction, was 6.6. And a [study of Twitter feeds published in 2011][5] found the average degree of separation between random Twitter users to be only 3.43.
Three hops is essentially *everyone* when your “suspected terrorist” pool parameters are essentially anyone who Googles the wrong thing from a non-US computer. Two hops is a lot of people, three hops is basically anyone — that’s how a “Foreign Intelligence Surveillance Court” authorizes *domestic* spying. If FISC rules that it *is* constitutional to spy on these enemies, **and** to follow those that they are spying on through three hops of communication, then FISC (which authorizes foreign spying) has essentially authorized domestic spying.
And this is the problem with only one side presenting information to the court — we can’t be sure that FISC judges were presented the right math. Maybe they thought it effected hundreds of thousands of Americans, not hundreds of million Americans. Maybe, or maybe they don’t care, shouldn’t we be allowed to know one way or the other?
[1]: http://www.bostonglobe.com/news/nation/2013/07/17/nsa-spying-under-fire-you-got-problem/Ev73I1XwPYtvD2WFZ6idGK/story.html
[2]: http://brooksreview.net/2013/07/three-hops/
[3]: Sean%20Gallagher
[4]: http://arxiv.org/pdf/0803.0939v1.pdf
[5]: http://www.aaai.org/ocs/index.php/SOCS/SOCS11/paper/viewFile/4031/4352