🚀 go-pugleaf

In article <1989Oct19.154929.19256@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes:
>In article <790@ariel.unm.edu> ee5391aa@hydra.unm.edu.UUCP (Duke McMullan n5gax) writes:
>>Expensive and easy to defeat -- probably...
>
>Most any non-digital scrambler, no matter how tricky, is probably going to
>fall under this heading.  There is lots and *lots* of redundancy in the
>human voice, and it's very hard to hide it completely.

I read a book on HF radio frequency assignments that said the Department
of Energy used a scrambler system for the trucks that transport nuclear
materials.  The system divided the audio spectrum into a number of
frequency bands and shuffled them around before feeding the audio into
the transmitter.  The interesting part of the system was the use of some
sort of key generator to change the mapping at a rapid rate.  I don't
know how difficult it would be to reconstruct the original signal by
attempting to match up parts of successive samples.  The nice thing
about this system was that it worked with conventional radio equipment. 

-- 
John A. Limpert			I'm the NRA!
Internet: johnl@n3dmc.UU.NET	UUCP: uunet!n3dmc!johnl