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Challenge "Zodiac Cipher"

Challenge "Zodiac Cipher"  

  By: admin on Aug. 2, 2010, 4:12 p.m.

In the late 1960s the so called Zodiac killer used a homophonic substitution encryption to encrypt letters to the police and the press. This challenge is inspired by the solved Zodiac-408 problem and the unsolved Zodiac-340 problem.Hint: Provide the codeword in capital letters.
Read more...

 Last edited by: admin on Oct. 31, 2021, 2:54 a.m., edited 1 time in total.

Re: Challenge "Zodiac cipher"  

  By: ThE_-_BliZZarD on Oct. 18, 2010, 2:04 p.m.

Well, I wrote a small program (in Delphi, in case someone cares) to analyse the file and do replacements for me. It's nothing fancy (replace works like in a Text Editor [HTML_REMOVED] ) but the frequency test may help, but it cant be this good as I still don't know the solution [HTML_REMOVED]
Edit: I solved it using my program, so it IS good [HTML_REMOVED]

HowTo: Open the ZIP file, extract the Zodiac.exe and run. Click "open input file" and open the txt file containing the cyphertext. Use the "replace" box to replace selected numbers with a letter, use "reset" to reset the cyphertext and after entering a replacement value click "Apply replacement". Using the small Boxon the bottom you csan change between Letter Frequency (frequency of every single number) and Twin Pair Frequenzy (frequenzy of specific pairs).

Download:
[attachment=0]Zodiac.zip[/attachment]
Uploaded.to
Netload.in

  • Current version: 0.125
  • Current CRC32: 7D2279CF
  • Current SHA-1: 751481D8E36C077E6501B5A3B108A1DDEF6BC343

Log:

  • 0.113 Initial release
  • 0.125 Bugfixes/Feature-Add (Output the password)

Feature requests and/or bug reports are appreciated :)

P.S.: I compressed the executable using UPX because of the size, but it is still too big to upload in this forum (max 256kb) Not anymore, attached the file!

 Last edited by: ThE_-_BliZZarD on Oct. 19, 2010, 10:49 p.m., edited 1 time in total.

Re: Challenge "Zodiac cipher"  

  By: Cream on Oct. 19, 2010, 4:07 p.m.

Hmmmm,

i am missing the starting point.
It says pen and paper.
Does this mean i now have to sit down and trial and error what's possible ?
Or is there a good method i can work with to reach the goal ?
And the last question:
The first line holds values from 1 to 17.
Is this just a count or how is this meant ?!?
As alphabet has 24 letters and this has 65 or so, some letters must be used in several numbers, that's ok.

i would like to hear a bit on the solution. i don't need some .exe file to do my work, even if i think it's nice, that u did it.
Otherwise i would like to look on your source code, not on the finished program.

Re: Challenge "Zodiac cipher"  

  By: ThE_-_BliZZarD on Oct. 19, 2010, 5:19 p.m.

The line from 1 to 17 continues up to 34 or something. This cipher works by assigning a number to every character until you run out of free numbers. This way multiple numbers may stand for one character. The first line(s) dont necessarily contain different characters, like this:
ABABABABABABAB transforms to 1 2 3 4 5 6 7 8 9 10 11 12 13 14A has multiple numbers and so does B.

Regarding my program: It does not "do the work" for you. It merely acts as pen and paper while you try out different Replacements. The Frequency Tests are nothing more than what CrypTool provides.
It is written in Delphi 2010 and there is some pretty version specific stuff in it, so it will not compile in older versions. And, like I said: It does NOT solve the cipher, it is just an electronic Pen&Paper program :) You'll see what I mean when you open it.

Re: Challenge "Zodiac cipher"  

  By: nobody on Oct. 20, 2010, 10:04 p.m.

Does this mean i now have to sit down and trial and error what's possible ?

Or you take more weight to the tip and start some background reserch … Ok, google is more like a random oracle than a paper, but very helpful =)

Re: Challenge "Zodiac cipher"  

  By: HermannSW on Oct. 24, 2010, 1:31 a.m.

I did this little JavaScript page as a replacement for pen and paper:
http://stamm-wilbrandt.de/mystery/mtc3- ... odiac.html

But this is just the replacement for pen and paper, not the solution …

Hermann.

(Tested to work for FF and IE – does not work with Opera, Chrome and Safari)
[img]http://stamm-wilbrandt.de/mystery/mtc3-stamp-03-zodiac.gif[/img]

Re: Challenge "Zodiac cipher"  

  By: joe_counter on Oct. 24, 2010, 8:26 p.m.

The line from 1 to 17 continues up to 34 or something. This cipher works by assigning a number to every character until you run out of free numbers. This way multiple numbers may stand for one character. The first line(s) dont necessarily contain different characters, like this:
ABABABABABABAB transforms to 1 2 3 4 5 6 7 8 9 10 11 12 13 14A has multiple numbers and so does B.

Regarding my program: It does not "do the work" for you. It merely acts as pen and paper while you try out different Replacements. The Frequency Tests are nothing more than what CrypTool provides.
It is written in Delphi 2010 and there is some pretty version specific stuff in it, so it will not compile in older versions. And, like I said: It does NOT solve the cipher, it is just an electronic Pen&Paper program :) You'll see what I mean when you open it.

Is this true, or does the 340 char text also resolve to a clear plaintext?
Meaning: Does this give two plaintexts, the decrypted 340 char plaintext and the 65 char password plaintext in english?

BTW: Nice connection to Zodiac (340)… [HTML_REMOVED]

I'm somehow lost.. [HTML_REMOVED]

Joe.

Re: Challenge  

  By: VLemos on Aug. 28, 2016, 8:53 p.m.

Okay, following the idea that each character is assigned to a different number until it runs out of possible numbers, I don't understand why it goes from 1-36 and then randomizes. Should't it be 1-65 and then start the loop again? Or do the letters that already have x numbers just repeat the numbers that are already assigned to them?

I'm lost here [HTML_REMOVED]

Re: Challenge  

  By: Konubixe on March 23, 2021, 9:53 p.m.

Last post from 2016? Ouwouw…

Got stuck at the input of the solution.

Have clear text and key. Can cipher clear text with key to ciphered text from challenge. So I thought solution is ok. Where is my mistake?

Re: Challenge  

  By: tryone144 on March 26, 2021, 1:12 p.m.

Hi Konubixe,

if you want to, please send me a PM with your solution and I will have a look at what could be wrong.

Greetings, Bernd


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