|
|
|
|
|
|
The M-190 is a cipher machine that is based on the Vernam
principle and belongs therefore to the mixer-class.
It mixes the signal from a clear-text paper tape with a
random number key-tape.
In the German Army the machine was often called LOMI after the Lorenz Mixer
on which the M-190 is based.
The machine belongs to the One-Time Tape
class (OTT), which is based
on the so-called One-Time Pad (OTP).
|
The picture on the right shows the machine with both the
clear-text tape and the key-tape present in the machine.
Before starting transmission, both sides of the communication link have
to ensure that the key-tape is at the same position.
Note the two large lamps (red and green) that are
prominently visible on the control panel. When the
red light was on, transmission was insecure, but when
the green light was on, the cipher system was enabled
and tranmission was safe.
|
|
|
The M-190 in the picture above is shown aside a Siemens T-100 (teletype)
terminal.
Both the clear-text tape and the key-tape are loaded into the machine and are
clearly visible. More images below. Click any of them for a close-up.
|
At the exhibition Secret Messages
held in Museum Jan Corver in the Netherlands
between October 2008 and February 2009, we had the opportunity
to connect two M-190 machines together in a small network.
The setup was used to demonstrate the practical use of OTT equipment
to the audience.
The image on the right shows former intercept-operator Louis van Erck (rear)
and Crypto Museum curator Marc Simons (front) each sitting behind
a Siemens T-100, exchanging messages at typing speed with an M-190.
|
|
|
|
Like most cipher machines of the mixer-class, the M-190 is not
(and never was) classified. It is the combination of the machine and
a NATO-issued cipher tape, that was classified as NATO SECRET.
Because of the fact that one-time pads (OTP) were used with the M-190,
it is impossible to use the machine to break old intercepts, as all
original OTP-tapes have been destroyed immediately after use.
Not many M-190 machines have survived as most of them were destroyed
in the early 2000s.
|
|
|
|
Any links shown in red are currently unavailable.
If you like this website, why not make a donation?
© Copyright 2009-2011, Paul Reuvers & Marc Simons. Last changed: Tue,27 Dec 2011.17:46:40
|
 |
|
|
