The 15-JULY-2013 Bruce Schneier CRYTO-GRAM email report is fascinating.
For those who don't know who Bruce Schneier is:
Following is a copy'n'paste of just the "NSA is storing voice content" portion of this month's l-o-n-gnewsletter:
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Evidence that the NSA Is Storing Voice Content, Not Just Metadata
There's been some interesting speculation that the NSA is storing everyone's phone calls, and not just metadata. The first link, below, is definitely worth reading.
I expressed skepticism about this just a month ago. My assumption had always been that everyone's compressed voice calls are just too much data to move around and store. Now, I don't know. There's a bit of a conspiracy-theory air to all of this speculation, but underestimating what the NSA will do is a mistake. General Alexander has told members of Congress that they *can* record the contents of phone calls. And they have the technical capability.
I believe that, to the extent that the NSA is analyzing and storing conversations, they're doing speech-to-text as close to the source as possible and working with that. Even if you have to store the audio for conversations in foreign languages, or for snippets of conversations the conversion software is unsure of, it's a lot fewer bits to move around and deal with.
And, by the way, I hate the term "metadata." What's wrong with "traffic analysis," which is what we've always called that sort of thing?
My previous skepticism:
More:
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