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Challenge "Cascading Encryption — Part 3/3"  

  By: Javex on March 29, 2013, 12:54 p.m.

Use the hints from the first and second part of this challenge to decrypt this message that has been encrypted using an ENIGMA.
Read more...

 Last edited by: admin on Oct. 31, 2021, 2:55 a.m., edited 1 time in total.

Re: Challenge  

  By: Veselovský on June 22, 2014, 10:25 p.m.

I programed my own simulator for the type of enigma that was used in this challenge.
I used this simulator as a reference to check that my simulator works correctly:
http://people.physik.hu-berlin.de/~pall ... 20_en.html

Once my simulator worked exactly same as the "Universal Enigma" simulator I started to search for the challenge plaintext.
After a week without success I gave up. Then I noticed (after discussion with other user who already solved the challenge), that in CrypTool2 the same type of enigma worked differently and realized that the challenge ciphertext was probably made by CrypTool2 and that I wasted my time for a week.

I have since found out what was the source of differences between these two simulators.

Now the question is. Which simulator of this type of enigma is correct, "CrypTool2" or "Universal Enigma"?

If the correct one is "Universal Enigma" I will be angry, so I hope you tell me that the correct one is "CrypTool2" ;-)

Re: Challenge  

  By: Veselovský on June 23, 2014, 12:38 a.m.

I found that "Universal Enigma" simulator…
"The code is verified against the “Enigma Simulator” coded by Geoff Sullivan"
http://de.wikipedia.org/wiki/Geoff_Sullivan.

So now it is two simulators against one CrypTool2.
It would need real Enigma to judge.

Re: Challenge  

  By: wackerao on June 23, 2014, 12:51 p.m.

For implementing the CrypTool 2.0-Simulator we used [1] as the base reference. In general, it is very hard to find good documentation about some of the details especially for the not-so-common variants of the Enigma. If you have some insight about what specifically we are making diferently and a reference, which says this should be done differently, we would be happy to adapt our code - and also the challenge. As you said, to really be sure we would need a real enigma (of this specific model).

Also, we did not find any histotric cipher-text to test our simulator against this. I also remember, that we had dicusssions about different descriptions in different references.

This explanation of course is no solution to the problem at hand. I think, in order to prevent misunderstanding we should state two things here:
1.) Yes, the challenge was made with CrypTool 2.0.
2.) We will compare our implementation with the universal simulator you mentioned and check for the differences. After that we can decide to re-publish this challenge. However, this will take some time.

[1] D. H. Hamer, G. Sullivan, and F. Weierud, “ENIGMA VARIATIONS : AN EXTENDED FAMILY OF MACHINES,” vol. 140, no. 3, pp. 1–17, 1993.

Re: Challenge  

  By: wackerao on June 23, 2014, 4:54 p.m.

An additional note for this challenge: The enigma model used in this part of the challenge uses one rotor of a different model (see hints from part 1 and 2). Therefore, this probably cannot be set in any simulator - therefore, if implementing something for this challenge, make sure that you use the additional rotor, as it will not work with a pure / correct enigma of the model which is used here.

Re: Challenge  

  By: NiKo on June 23, 2014, 6:14 p.m.

Hello there :-),

I just had a look at the "Universal Enigma - Simulator by dp" and found out that the entry rotor differs from the one described in the used paper [1] for CT2. They, and we @ CT2, us for the ETW:

ETW => QWERTZUIOASDFGHJKPYXCVBNML

the simulator uses

ET => JWULCMNOHPQZYXIRADKEGVBTSF

which comes from the commercial version enigma D. See http://de.wikipedia.org/wiki/Enigma-Walzen

so there seems to be a "failure" in the simulator.

We also found out, that someone changed the rotors in the CT2 version of the enigma AFTER wackerao D. H. Hamer, G. Sullivan, and F. Weierud, “ENIGMA VARIATIONS : AN EXTENDED FAMILY OF MACHINES,” vol. 140, no. 3, pp. 1–17, 1993.

Re: Challenge  

  By: Veselovský on June 23, 2014, 10:05 p.m.

the entry rotor differs from the one described in the used paper

Well, they use the same rotor but differently.

universal enigma simulator uses it at input this way:
QWERTZUIOASDFGHJKPYXCVBNML -> ABCDEFGHIJKLMNOPQRSTUVWXYZ
(which is equivalent to
ABCDEFGHIJKLMNOPQRSTUVWXYZ -> JWULCMNOHPQZYXIRADKEGVBTSF as you wrote)

Cryptool2 uses it it at input this way:
ABCDEFGHIJKLMNOPQRSTUVWXYZ -> QWERTZUIOASDFGHJKPYXCVBNML

I do not know which way correspond to historical enigma, but maybe the entry rotor can be rotated 180 degrees inside enigma and still fits? If so then maybe someone who was restoring/preserving old enigma made that mistake and that is why we have two different simulators now… or maybe it is just programming mistake that does not have to do anything with enigma.

Re: Challenge  

  By: fmoraes on Nov. 21, 2014, 11:15 p.m.

An additional note for this challenge: The enigma model used in this part of the challenge uses one rotor of a different model (see hints from part 1 and 2). Therefore, this probably cannot be set in any simulator - therefore, if implementing something for this challenge, make sure that you use the additional rotor, as it will not work with a pure / correct enigma of the model which is used here.

Can the challenge be solved using CrypTool 2? I didn't see an option to use the extra model rotor in it.

Re: Challenge  

  By: Veselovský on Nov. 22, 2014, 3:14 p.m.

Can the challenge be solved using CrypTool 2? I didn't see an option to use the extra model rotor in it.

As far as I know this challenge cannot be solved with CrypTool 2 at this time.

Re: Challenge  

  By: D3d4lu5 on March 10, 2019, 4:48 p.m.

I already solved this challenge, but I could not reconstruct the entire plaintext.

Do I have to test the ring and stecker positions too?

Re: Challenge "Cascading Encryption — Part 3/3"  

  By: RogueRamblers on Nov. 27, 2023, 6:39 p.m.

If https://www.cryptomuseum.com/crypto/enigma/ is accurate, some of the enigma implementation details in Cryptool 2.1 may be incorrect.

  1. According to a page on this site, Cryptool matches the rotor (including the UKW) wirings as recovered by Bletchley Park. But the site gives different wirings that match actual recovered machines.

  2. The notches used by Cryptool for the machine used in this challenge match the 'Notch' column in the reference and other documents, not the 'Window' column (the letter shown in the window when stepping occurs). This is not consistent with other machines supported in Cryptool.

  3. Cryptool does not provide an option for moving the settable UKW start position.

BTW, I have not used Cryptool in the past because I find writing my own tools to be most of the fun in working on challenges. While using it to investigate why I had trouble solving this challenge I became very impressed by it!

 Last edited by: RogueRamblers on Nov. 28, 2023, 2:33 a.m., edited 1 time in total.

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