Challenge "Trifid Cipher"  

  By: admin on Oct. 28, 2013, 8:49 p.m.

Two scatterbrained professors exchange messages that have been encrypted with the Trifid cipher. Unfortunately, one of them lost the second of three layers. Will he nevertheless be able to decrypt the message he received from his colleague?

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

Re: Challenge  

  By: aurelie on Jan. 13, 2014, 12:05 p.m.

Wie soll man auf die richtige Anordnung der Buchstaben in Layer 2 kommen?

Welche Buchstaben in Layer 2 vorkommen, sollte offensichtlich sein: das Alphabet hat 26 Buchstaben, 17 sind schon in Layer 1 und 3. Die anderen 9 müssen in Layer 2.

Ich habe bei der Aufgabe zur Trifid-Chiffre 171 Buchstaben gezählt.Das bedeutet,wir haben 523 Zahlen,da jeder Buchstabe mit 3 Zahlen(Layer,Spalte,Zeile)dargestellt wird.Ich habe also die ersten 57 Buchstaben fortlaufend in einer Zeile dargestellt,darunter die nächsten 57 und in der dritten Zeile die restlichen 57 Buchstaben.Beim Entschlüsseln ist dann nur Unsinn rausgekommen.Können Sie mir einen Tipp geben,was ich verkehrt gemacht habe?

Zum weiteren Vorgehen: Probier den Chiffretext wie im Beispiel zu entschlüsseln. Über einige Buchstaben hast du bereits alle Informationen, weil sie in Layer 1 oder 3 stehen, bei den anderen ist bekannt, dass sie in Layer 2 sind (also werden sie durch 2SZ codiert, wobei S und Z für die noch zu bestimmende Spalte und Zeile stehen).

Ich hoffe, das hilft dir, ansonsten kannst du hier gerne weitere Fragen stellen, die wir gerne beantworten.


  By: ExAstris on May 20, 2018, 4:55 p.m.


I am very familiar with the Trifid cipher, but when I follow the instructions in the PDF, I don't get anything meaningful.

According to the PDF, I should write the CT in 3 rows of 57 characters, then write the triples given by the tables.
For example EMKE would yield ……122…, since only K is given (122). So I do this for the 3 rows and get mostly dots, but some very partial PT.

If I find a block like this, where G=133 and U=321 (from PDF), and replace the other letters:
`G U R F F K

133312 332311 311122

By reading the triplets vertically, I get some PT. However, it doesn't make sense (for example QQ or JP).

So, am I missing something ?



Re: Challenge  

  By: RandyWaterhouse on Aug. 2, 2019, 8:11 a.m.

Hi Eric,

a very late answer to your question (I'm new to Mystery Twister):

There are only 9! = 362880 possibilities for filling layer 2. I wrote a small Python program which checks every one of them, decrypts the ciphertext and searches for "cribs", i.e. meaningful words. Only when several simple cribs are found the text is printed to the screen.

With that I was able to recognize parts of longer and more significant words in the text. Using them again as cribs a unique solution quickly emerged.

Hope that helps?

Best, Peter

Re: Challenge "Trifid Cipher"  

  By: BOBTMSJ on May 10, 2022, 11:28 p.m.

For those to run into Eric's problem, consider the hint: "The plaintext has been encrypted line by line." Don't grab all of the CT and put it into 3 rows of 57 characters. Take it one line at a time.

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