Re: Enigma Settings Sheets

Thank you to both Phil and Frode for your excellent answers, it's good to
see that there are experts still on this list!

I find it interesting that our understanding of these settings procedures
seems still largely based on what was pieced together by the attackers at
BP, but that's understandable given the lack of surviving primary sources
from the German side.  There is the material that was collected by US TICOM
immediately after the war, like Frode's Luftwaffe settings sheets, and I
presume the settings sheet provided to Phil by Tony Sale was from the BP
archives, perhaps from a wartime "pinch"?

How does one go about getting access to these primary sources?  I know
there's a digitisation project going on at BP:
http://www.bletchleypark.org.uk/edu/archives/ , I suppose I should just go
and ask them, as I have the convenience of living just an hour's drive away
:-)  Does anyone know about getting access to the TICOM stuff?  It's many
years since I last visited the US National Cryptologic Museum, do they hold
those materials?

> The Luftwaffe cipher office appears to have had some odd ideas about the
nature of randomness

Indeed.  It could be a positive feature of any security system that the
design looks secure to the uninitiated, provided that doesn't appreciably
worsen the underlying security but clearly in this case it did.  I
exchanged some email with Ralph Simpson recently, speculating that this may
be why the Transvertex HC-9 was set up not to encrypt letters to themselves
even though it was physically capable of doing so.

> In my article I noted that late in the war someone in the Luftwaffe
cipher became lazy and started constructing UKWD pairings by reusing
stecker pairings from other keys.

Thanks for that pointer, I reread that part of your article and I see you
refer to a document that is held by the US National Archives and Records
Administration, RIP 403 ... "Special British Reports on German
Cryptography" - I don't suppose that document is available online
anywhere?  I'm particularly curious about how they would create sets of 12
reflector pairs from sets of 10 plug-board pairs, if anyone can explain
further?

Re difference between M2 and M3:

>   1938                    310                M 1112 – M 1421       M 2
>   1939                    580                M 1422 – M 2001       M 2a,
M 3

I'll watch out for examples from these serial number ranges and see if
there are any visible differences.

> Both Enigma C and D had the notches fixed to the wheel body and not on
the alphabet ring

Excellent, thanks for clarifying that!

Cheers,

- Craig.