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- Newsgroups: sci.crypt
- Path: sparky!uunet!paladin.american.edu!gatech!swrinde!network.ucsd.edu!qualcom.qualcomm.com!servo.qualcomm.com!karn
- From: karn@servo.qualcomm.com (Phil Karn)
- Subject: Re: Motorola 'Secure-Clear' Cordless Telephones
- Message-ID: <1993Jan2.234049.27767@qualcomm.com>
- Sender: news@qualcomm.com
- Nntp-Posting-Host: servo.qualcomm.com
- Organization: Qualcomm, Inc
- References: <C05JAM.MJL@ais.org> <1993Jan2.174522.12032@qiclab.scn.rain.com>
- Distribution: na
- Date: Sat, 2 Jan 1993 23:40:49 GMT
- Lines: 21
-
- 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
-
