Genuine messages

The first message

Introduction

In the brochure accompanying the promotion of his first encryption machine using only a single rotor: “Commercial Portable Code”, Hebern gives examples of pairs (clear / cryptogram) with the encryption key (the first letter of each cryptogram [V , D, O, B]).

The messages

 Grand Fleet of Transports, lives as a Load
VOMOQJ WJWJW CG VFMBJDTFZK, TNNYE GN S NMBI

 Submarines of the Ocean, Have Copies of Codes
DVZKHSFJBWN TR ZTZ XQYRZ, BSEK HQROFU FZ UUABJ

 Disaster Appalling Waits Fates Changing Look
OGAKORSYA GMBFTFDHY  HNBG ADKQY XTOIBGKA JTRE

 Dangerous Policy, Using Code Made From Books
BVJHYFZFWG GCMDAM, AXGLFO XAUV OBIJ KTTF TFULN

Messages and basic key

These messages are very valuable for the historian: they make it possible to deduce the basic key to the first version of the Hebern 1 rotor machine.

The rotor advances before encryption.
Rotor Advancement: CounterClockwise (trigonometric).
The letters on the rim of rotor are in Clockwise direction.
Note: the patent drawings show the letters of the rotor in the trigonometric direction (see note).
We work in encryption (or decryption?) mode.
Note: because the Rotor is symmetric, there is no difference between encryption and decryption.
Rotor : PI = FTQJVAXMWDSNHLRUCOKBPEIGZY
Lampboard = Keyboard = Identity

Note: the direction of advancement (trigonometric) seems strange to me. Indeed, all the examples given by Dawson are decipherable only in clockwise mode. On the other hand, the Hebern 5-rotors machine works in this direction (clockwise). Finally, the letters around the edge of the rotor (which is in the trigonometric direction), suggest rotation of the rotor in a clockwise direction. It's a little mystery.

There are errors in the cryptograms

Using the previous key and my simulator, I noticed that there are errors in the original text:

	GRANDFOEETOFTRANSPORTSLIVESASALOAD
	SUBMARINESOFTHEOCEANHAVECOPIESOLCODES
        DISASTERAPPALLING?MITSFATESCHANGINGLOOK 
(we have added a letter to the cryptogram, it appears like a 
 a "?" in plain text. I thing there are a "II" in place of "H"
 in the cryptogram which can be deciphered by "WA")
	DANGEROUSPOLICYUSEINGCODEMADEFROOBOOKS

C:\H1_TOOLS>  echo OMOQJ WJWJW CG VFMBJDTFZK, TNNYE GN S NMBI | ^
    python hebern1_tui.py -R =FTQJVAXMWDSNHLRUCOKBPEIGZY -t -T -E V
GRANDFOEETOFTRANSPORTSLIVESASALOAD

The second message

Introduction

On Nick Gessler's site (see Web links below), we can see an encrypted message with the corresponding plaintext produced on a Hebern 1-rotor machine. Wiring is provided but does not allow (directly) to verify the encryption.

The information given

On Nick Gessler's website, you can see a rotor numbered #5. This number (5) replaces the letter Z around the edge of the rotor.

This information is very interesting: if this rotor is numbered, we can think that the machine was delivered with a set of rotors. At a minimum, if only one rotor has been supplied, the owner of the machine can purchase others.

This rotor belongs to a Hebern 1-rotor machine equipped with a light panel. Nick's site gives photos of the machine and the rotor.

- Nick gives the wiring of the rotor:

    UNKYFEXVZOCTPBJMSWQLAHRGDI

- As well as the following encrypted message:

    ZBJMJ-VISXM-FDYVC-IUOFR-VRGOS-F

- Nick specifies that the corresponding plain text consists of the letter A repeated 26 times. The key used being A.

Note: The test cryptogram above is identical on two machines: Nick Gessler's and Mark Sim's. We deduce that the two machines used the same rotor.

My rotor wiring rebuild

I managed to reconstruct the real wiring and then I managed to verify that the deciphering corresponds to a sequence of A. In fact, the wiring given by Nick is offset from the real wiring.

Here is the real wiring:

    FTQJVAXMWDSNHLRUCOKBPEIGZY

Here is the decryption carried out with my simulator:

H1_TOOLS> echo ZBJMJ-VISXM-FDYVC-IUOFR-VRGOS-F | ^
    python hebern1_tui.py -R =FTQJVAXMWDSNHLRUCOKBPEIGZY ^
    -t -E A
AAAAAAAAAAAAAAAAAAAAAAAAA

Note: The rotor (FTQ...) is the first rotor used in Dawson's book (p17). It is reciprocal (decryption is equivalent to encryption). We can see that the Keyboard and Lampboard permutations are equal to the Identity permutation. We also can see that the Nick's machine uses the trigonometric mode for rotor advancement.

- Here are the Dawson rotor offsets:

      5, 18, 14, 6, 17, 21, 17, 5, 14, 20, 8, 2, 21, 
      24, 3, 5, 12, 23, 18, 8, 21, 9, 12, 9, 1 , 25

- Here is the start of the offsets given by Nick:

   D->Y:  -5
   C->K: -18
   B->N: -14
   A->U:  -6
   Z->I: -17

As we can see, the wiring given by Nick is correct...but shifted!

Conclusion

In both messages, the direction of advancement of the rotors is in the trigonometric direction unlike the 5-rotors machine.

We can notice that in the machines used in the two messages the Keyboard and Lampboard permutations correspond to the identity permutation. This is another difference with the 5-rotors machine.

On the other hand, the letters on the rim of the rotor were clockwise for the first message, and counterclockwise for the second message.

Note: On the National Cryptologic Museum website, I was able to see rotors with their edges in the two directions mentioned above.

Finally, both messages were encrypted with the same rotor (FTQ...). Thus, we only know the wiring of three 1-rotor machines, and it is the same for all three!

References

Machine Cryptography and Modern Cryptanalysis, by Cipher A. Deavours & Luis Kruh, From Artech House Telecom Library, 1985.
Cryptanalysis of the single rotor cipher machine, by Donald A. Dawson, Aegean Park Press, 1996.

Web Links

Nick Gessler - The Hebern Code Machine. (link).
National Cryptologic Museum. Browse the collection (link).
Note: You can search by keyword. If we use the word "Hebern", we get several photos.