Mar 242013

Inspired by the Enigma World Code Group page, I have created a collection of key tables for the M-209 cipher machine for use by collectors and cryptography enthusiasts. This publicly-available collection of key tables, much like the code sheets on the Enigma World Code Group site, provides a set of ready-to-use M-209 keying material for M-209 aficionados to use. Obviously, openly published key tables don’t provide any real security, but they can be used by hobbyists to exchange M-209 cryptograms without needing to generate and distribute keying materials first. These key tables can be used for educational and entertainment purposes. The WW2 era technical manuals for the M-209 describe a method of indicating to message recipients which key table to use and which initial key wheel settings to use, by inclusion of some specially-formated 5-letter groups at the beginning and end of each message. This technique was used by US forces during WW2, as shown by captured, translated, and eventually declassified German accounts of their cryptanalysis of M-209 traffic. This method assigns a two-letter identification code, or “key list indicator”, to each key table. I created this key table collection by using my own M-209 simulator to generate 676 new key tables, assigning them key list indicators AA through ZZ. Most of them are freshly generated, except for tables MB and FM which match key tables that I distribute as samples with my simulator. The entire collection is hosted on GitHub:

You can download the whole collection as a zip file or compressed tar file:

Here is a direct link to the FM key table, which has traditionally been used in MRCG field events:


I am presently working on a series of posts which explain in detail how to operate an M-209 cipher machine. At this time, I have published the first part, and I’m working on part 2. Enjoy!

Update, 2013-04-03:

The files in the zip and tar archives above are all plain text files. They have UNIX/Mac style line endings (LF only), so Windows users will need to either open them with a program that can understand UNIX style text files, or convert them to DOS style line endings (CR+LF). The Notepad program that comes with Windows does not handle UNIX style text files well. My own M-209 simulator happily digests them. You may rename the files with “.txt” extensions if you wish, but note that my M-209 simulator expects the files to have “.m209key” extensions when using the -a automatic mode.

Update, 2013-04-30:

I’ve just launched the M-209 Cipher Machine Group, which is an informal club for M-209 enthusiasts who wish to exchange M-209 cipher messages. Please note that I’ve generated entirely new key lists for that group with a daily key change schedule, and those key lists should not be confused with the collection of key tables on this page. Even where the key list indicators match, this collection does not contain any of the same key tables as the ones generated for the M-209 Cipher Machine Group. I hope this doesn’t cause any confusion.

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