[CW] ENIGMA

[D.J.J. Ring, Jr.]

>From R/O Dave, I believe he lives in Ireland now.  But he has some
words about ENIGMA.

73
DR

---------- Forwarded message ---------
From: g4jht <g4jht at eircom.net>
Date: Mon, May 6, 2019 at 11:01 AM
Subject: Regarding Enigma.
To: D.J.J. Ring, Jr. <n1ea at arrl.net>


Hi Dave, hope you enjoying England and the Wx when it improves - very
cold here.  Read you item on your trip to PB (Bletchley Park), and Enigma.

Unfortunately sound like you have been fed a certain amount of garbled
or misinformation.

Now while I do not claim to be an expert on Enigma - to my mind only the
teams that worked on Enigma both at BP, PC BURO - Paris,  and in the
CMEIB Cairo, during WWII  warrant that title.

I have been studying the various types of Enigma every since I first got
a copy of Walchman's book The Hut Six Story in 1983/84.

I can tell you for instance there never was an Enigma with 5 rotors.

I will leave you to Google Enigma, and read the Wikipedia description of
how the internals of an Enigma machine scrambled the input text.

What the Poles intercepted via the railway parcels office in Warsaw was
a modified version of a commercially available early Enigma. What I
term  Nazi Mk1 Enigma.
At that time it simply had a different set of rotors just three inside.

It was only in the late 1930s that the steckerbratt (plug board) was
added. This provided an additional level of scrambling to be added to
produce Nazi Mk 2 Enigma  .

The next change was to increase the number of rotors in the set provided
with the machine to 5, but at any one time only 3 rotors were actually
mounted in the machine. This machine is generally referred to as a
"Three-rotor Enigma" or Enigma G.

The German Navy, first added 3 more rotors to the set to permit
selecting any 3 from 8  (1940), so still a 3-rotor machine.
On 1 February 1942, the German Navy, introduced a new enigma machine
with 4 rotors inside for use by U-boats; the  Nazi Mk 4 Enigma  or  M4
Enigma   This was introduced for U-boat traffic , and proved much more
difficult to break. And it is this 4 rotor machine and the key setting
books that were "pinched" by the RN boarding party from the sinking
U-boat with members of boarding party awarded VC after they failed to
get out in time.
the M4 Enigma required 100 times more effort to break, and took until
December 1942 until it was being done regularly. This ultimately lead to
the defeat of the U-boat.

Dave all above is from memory - I am almost 80 y.o so my memory is not
as good a it was.  When you get back you have few leads to follow up.
Welchman's book The Hut 6 Story has a good description of Enigma
internals and the breaking process step by step.

enjoy your time in the UK.

best 73s, Dave. :-)