Optical Tempest? I have my doubts...

Major Variola (ret) mv at cdc.gov
Thu Jul 17 12:46:43 PDT 2003


At 03:15 PM 7/17/03 -0400, Tyler Durden wrote:
>I dunno...I'm thinking that optical tempest is probably bullshit 99% of
the
>time, but what do I know?

There was an article on optical tempest based on reading modem-LEDs,
which are sometimes modulated with the data stream.  For Mhz rates it
works.

>But I still don't believe that specular reflection of smallish type
from a
>monitor will have anything that is recoverable. Of course, this is
going to
>be dependent on the quality of the wall material, but for most
not-so-even
>plaster/drywall painted surfaces, I just can't believe the appopriate
>spacial frequencies of the image are not scattered after that kind of
>reflection.

The idea of reading the *matte* reflection of the CRT beam is possible.
But its not *spatial* frequency, its using intensity vs. time.
At any one instant you have a single 1-D measurement.
This exploits the fact, as stated, that the phosphor is brightest under
the
(scanning) beam.  There is no spatial info present.  You simply need
a sensitive (contrast is low) and fast (raster rate) optical
measurement.

>The conspiracy theorist is telling me there's some reason they floated
the
>optical tempest story, though I can't quite figure out what that reason

>is...

Its the Windowshade division of the Anti-Illuminati


----
Irony:
Jewish Zealots were famous for offing (Jewish) Roman collaborators.
100 generations later, Arabic Zealots whack (Arabic) ZionistCrusader
collaborators.
"Pro-American Mayor, Son Killed in Iraq"

----
Of course Iraq isn't another Vietnam.  They don't know how to make good
pho hoa.





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