[GreenKeys] Cryptography

[Duncan M. Brown]

Yes, teleprinters have been used in cryptology. One method (used during
WWII, I belive) was a tape transmitter with two readers. One read the clear
text and the other read the "key". The signals of the two tapes were
exclusive OR-ed together and sent out.  At the other end, the encrypted
signal was punched into a tape and then exclusive OR-ed with the key again
to produce the clear text.

Somewhere I saw a listing of Teletype Corp. model numbers and everything
above "50" was listed as "classified."

At the AWA museum, I just found what appears to be a Teletype Corp. "Type
61 Coding Unit"  (no mfr label or model nameplate, just a paper tag).  It
looks like M14/15 vintage and has a M14 tape reader on the front with a
"cipher ON/OFF" switch on it.  The unit is about a foot cube.  There are at
least a dozen relays under the chassis.  But there is a place where a
module about 4" on a side has been removed (lots of cut wires), which was
probably the actual encryption part.  Does anyone know anything about a
Teletype Type 61?

--Duncan, K2OEQ
http://www.antiquewireless.org/



> [Original Message]
> From: Fred Tegge <n9ftfred at hotmail.com>
> To: <greenkeys at mailman.qth.net>
> Date: 30-Nov-06 20:47:47
> Subject: [GreenKeys] Cryptography
>
> Does anyone have any idea if teletypes were used for cryptography in the 
> 1940's and 1950's, if so how??
>
>
>
> Fred Tegge
>
>
>
> 920-205-6685
>
>
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