?

Log in

No account? Create an account

March 18th, 2003

Hollywood Computer Science (Fiction)

My brother-in-law rented the latest Bourne Identity movie.  Its NSA/CIA scenes had some fantastical computing power; the kind of that popped up in [the other movie he rented] and all the other movies I've seen by Hollywood, so I did a little number crunching to see how much power the NSA, CIA, and military evidently have according to the gullible.

So there's about half-a-dozen survelliance cameras in a train station that the uber-evil CIA agents can just "tap into" back at their command center.  Uhuh.  Let's assume one of these cameras encodes MPEG-2.  Why?  Well the goons in these movies typically zoom onto the ID badges, license plates, and other stuff that generally become big blobs at lower quality codecs.  Something like MPEG-4 pixelates too much; try zooming into text from a flash movie off YouTube.  So we have our first problem: quality versus bandwidth.  

Let's assume the mp4v (video) stream is magically funnelled directly to the command center.  That sucks up 15Mbps -- for one camera.  As a comparison, people typically buy 3 or 5Mbps pipes from ISP's but, of course, the CIA isn't just any residential consumer.  The command center must have purchased a phat pipe from AT&T, Level3, or Verizon (NTT).  Those are the telco carriers that I've seen on the Internet backbone that can push data at DS3 rates or higher.  The more cameras ... say 6 streams ..., the fewer circuits that the carrier could dedicate for upto 90Mbps.  Has the CIA purchased an OC3 just for this command center?  Maybe, but keep in mind that the cameras on the other end need to be funneled through this circuit too.  Did the London Transit Authority buy a phat pipe for their train station?  Hah.  Probably not on the off-chance that the CIA wants to snoop on their closed-circuit survelliance cameras.  Yea, it's called "closed circuit" for a literal reason.  

This is all a simplistic criticism.  In actuality the CIA would probably never tap into each camera directly but hack into the train station's local video server(s).  This is more complicated but would circumvent the typical way that high bitrate survelliance cameras are connected (via coax cable; a broadcast medium -- difficult to route over the Internet without some local hardware also being hacked, like a router at least).  Even this hack happened all rather quickly in the movie.  The CIA must have merely reconnected to an already hacked network.  Regardless of the impracticality of the on-the-fly hacking or networks that have been already hacked en masse by the CIA, we still can't circumvent the upload bandwidth that the train station's routers and switches must allocate for the video streams to the command center.  

As an aside, neither the encoding of the video stream (by the command center if the data is lifted directly from the camera's network) nor the decoding of the video stream (when the command center's sytems display the images) are considered in my criticism, and both must be done by some dedicated CIA hardware because the streams are being processed in realtime.  We're talking about banks of digital video cards in clusters of servers (aka. processors) to be able to scale above a few streams with realtime zooming.  The CIA's command center could act like a cable TV provider by funnelling all these streams -- with a catch: instead of merely tapping into broadcast connections, also tack on connections to endpoints like the train station that can be snooped on-the-fly.  I'm not saying it's impossble, but I think there are limitations imposed by the kind of data that the film is depicting can be trivially sniffed from the Internet.  That's coming from someone who thinks that it's fairly trivial to snoop on VoIP conversations.  But a 64kbps voice stream is a significantly different playing field than MPEG-4 video.  Something like the G.711 audio codec isn't CD quality; it doesn't have the quality needed by CSI agents to extrapolate noises ... still, the CIA could snoop over 20 calls via phone at CD quality or one survelliance camera at TV quality.    Yea. They're probably listening in on your phone conversations yet have no idea what you wore to the mall.  :)