[3285] in cryptography@c2.net mail archive
"M1 Analog" to Enigma at the National Crypto Museum
daemon@ATHENA.MIT.EDU (Steve Bellovin)
Mon Sep 14 19:34:43 1998
From: Steve Bellovin <smb@research.att.com>
To: cryptography@c2.net
Date: Mon, 14 Sep 1998 19:23:33 -0400
I stopped in today at the National Cryptological Museum outside NSA.
There were some minor perturbations to the exhibits since I was there
last; the interesting thing, though, was a device I hadn't heard of
before: the "M1 Analog" to the Enigma. It was supposedly used for
decrypting messages after the key had been recovered. Its design
makes me suspect that there was more to it than that, however.
Instead of 26 letter keys, it had toggle switches for each letter.
Flipping a switch thus illuminated a light for a long period without
fatiguing the operator; it also didn't advance the rotors, most likely
(the device was in a glass case, so I couldn't play with it). There
were 5 rotors visible; the right-most three had the expected letters.
The other two were unmarked, as best I could tell. One, presumably, was
the reflector; I have no idea what the other was. Beneath each rotor
was a key that presumably caused it to step; this included the leftmost
two rotors.
>From the design, I assume that the M1 was also used to correct garbles,
and to try alternate characters and lengths in received messages. The
presence of two reflector rotors would tend to confirm this. Does anyone
know any more about this device?
