🚀 go-pugleaf

In article <1993Jan2.174522.12032@qiclab.scn.rain.com> Leonard.Erickson@f51.n105.z1.fidonet.org writes:
>And according to several histories of cyprtology I've seen, one of the
>reasons the US & Britian *quit* using frequency inversion scramblers
>for calls between Churchill and Roosevelt was that the techs working
>on the system reported that with practice it became possible to understand
>the inverted speech! 

Another is that Bell Labs developed a truly remarkable (given the
technology of the day) secure speech system that really was secure. It
used voice coders (vocoders) and one-time-pads generated by recording
the electrical noise from mercury-vapor rectifier tubes on phonograph
records.  After two pressings were made, the masters were destroyed.
One copy was kept in the US and the other was shipped to London under
the careful watch of a Marine guard. After being used once to protect
a Roosevelt-Churchill conversation, each pair of discs was destroyed.

I believe that the German intelligence experts said after the war that
this was the only Allied secure speech system they were never able to
crack.

Phil