Quote:
It is entirely possible that the NSA technology at issue here is some kind of high-volume, automated voice recognition and pattern matching system. Now, I don't at all believe that all international calls are or could be monitored with such a system, or anything like that. Rather, the NSA could very easily narrow down the amount of phone traffic that they'd have to a relatively small fraction of international calls with some smart filtering. First, they'd only monitor calls where one end of the connection is in a country of interest. Then, they'd only need the ability to do a roving random sample of a few seconds from each call in that already greatly narrowed pool of calls. As Zimmermann describes above, you monitor a few seconds of some fraction of the calls looking for "hits," and then you move on to another fraction. If a particular call generates a hit, then you zero in on it for further real-time analysis and possible human interception. All the calls can be recorded, cached, and further examined later for items that may have been overlooked in the real-time analysis.
