Monday, December 19, 2005

Small world networks and the NSA

Let's say you get ahold of a foreign phone number that belongs to someone that's a terrorist or a known associate of a terrorist. Of course the NSA is going to tap that phone and that wiretap will not require a warrant. But what other information can you get from that one number? You get a list of all of the numbers that are dialed out of the phone and the numbers that dial into the phone.

What if some of those numbers are in the US? The NSA is not allowed to monitor the contents of those communications without a warrant. But the NSA can monitor if those US phones call overseas. The contents of the call require a warrant, but the act of calling does not.

So why not get a warrant for each time you want to see where a US number dials an overseas number? Scope. This would be an automated system that acts in a very quick fashion. Each call to a foreign number would then peg that number as another watch number, then the process would start again. Such a system would quickly overwhelm the FISC with requests and most of the requests would, rightfully, be denied.

So what purpose does all of this to and from traffic monitoring serve? That's where the former TIA program comes in. While a huge list of cross-referenced numbers may not mean much for you or me, we are really having computers find patterns. Using the theories behind small world networks you can cull and correlate that information and begin to develop a better picture of how terrorist networks interact. The earlier post about LiveJournal is a simpler example of the scale the NSA would operate on.


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