Building an Enigma code book

[MuscleBob.Buffpants]

I am in the process of developing a .NET application that will generate the wheel, ring and stecken positions for a four rotor Enigma. The design will produce semi-random numbers - that is, each version will produce the same combination of letters and numbers for the day selected - if you select September 14, 1941 and so does someone else, the postions of rings, wheels and stecken will be the same.

Basically it is a software code book

I am just doing it for a programming exercise to keep my brain working, but if anyone out there is interested then I will look at getting the final version hosted somewhere.

I don't know if this should be in the mod section, but it's not really a mod so please feel free to move it Moderators ;)

[Vader 1]

This site might help you witht the code book

http://www.geocities.com/atlantikcampaign/ac_8.html

I play in this league and regularly recieve patrol info via an Engima message. It always shows the "Data Date" at top of message inorder to set machine to same setting as message.
?? pm Raptor or Bdu

Vader( now Korth in Atlantik campaign)

[clive bradbury]

I do like the sound of this - please make it available - I will host it on my site if you need somewhere.

[terrapin]

I am in the process of developing a .NET application that will generate the wheel, ring and stecken positions for a four rotor Enigma. The design will produce semi-random numbers - that is, each version will produce the same combination of letters and numbers for the day selected - if you select September 14, 1941 and so does someone else, the postions of rings, wheels and stecken will be the same.

Basically it is a software code book

I am just doing it for a programming exercise to keep my brain working, but if anyone out there is interested then I will look at getting the final version hosted somewhere.

I don't know if this should be in the mod section, but it's not really a mod so please feel free to move it Moderators ;)

contact me if you want that one hosted on our site :)

[enigma-e]

Awful sorry to disappoint you, guys, but there is already an Enigma Forms Generator (http://www.xat.nl/enigma-e/support/efg.htm) online, including a code book and a message form generator.

Oh, and BTW: The code books on "Atlantik!" were also generated with this tool, although the site owner has clipped the cover leaf to make it look like his own work.

[MuscleBob.Buffpants]

Took a look at the form generator and it is fine for that application, but it means sending documents around for people to use.

This is more a software form in one small app that doesn't require printing and/or searching pages of info to find the data you want.

I am going to proceed anyway and leave it for anyone who wants to use it.

Cheers

[clive bradbury]

Hi Enigma. I like the form generator, but please help me in my ignorance - what are the 'kenngruppen' settings in the codebook for?

[enigma-e]

@clive:
The Kenngruppen are the rotor settings visible through the slots on the surface of the Enigma.

While the general Enigma settings (rotor settings, internal rotor settings, Stecker settings) are changed only once a day (at 0:00 hrs) and stay unchanged for the remainder of the day, the outer settings of the Walzen (rotors) are changed at specified intervals.

There are always four Kenngruppen to each day. The first one is used from 0:00 to 06:00 hrs, the second from 06:00 to 12:00 and so forth.

This is yet another weakness of the German Enigma concept. Important messages had to be repeated several times by the BdU, cause some subs might be underwater by the time the message was sent.

So, the plaintext had to be encoded again, this time with a different set of Kenngruppen. Since no letter typed on an Enigma will ever be encoded into itself, and the two messages having the same wording, each letter at its respective place could be excluded to be at that place in the plaintext. This gave the decoders at Bletchley yet another "crib" as to what the message meant. It might even give Bletchley a clue as to a whole day's settings, if the text was reencoded with a new days's settings.

@Muscle: It doesn't mean to send documents around at all. The code book could be deposited as a .pdf file on a web site for all authorized to see. But allright, you just go and re-invent the wheel.

[clive bradbury]

Thanks, enigma. I guessed they were the wheel settings, but I didn't realise they had four sets per day, which is what confused me.

Mind you, I'm easliy confused...