Hill Cipher- Potential Cribs for 3x3 Matrix

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SUMMARY

The discussion focuses on strategies for cracking a Hill Cipher with a 3x3 matrix. Participants emphasize the importance of selecting appropriate cribs, specifically 9-letter phrases, to facilitate the cryptanalysis process. Suggestions include using common phrases related to the context of the message, such as "hillcipher," while also considering the constraints of modulo 26 for letter encoding. The conversation highlights the need for a deeper understanding of the source and potential phrases that could have been used in the original message.

PREREQUISITES
  • Understanding of Hill Cipher encryption and decryption techniques.
  • Familiarity with cryptanalysis methods and statistical tests.
  • Knowledge of modulo arithmetic, specifically modulo 26 and modulo 27.
  • Ability to identify and formulate potential cribs based on context.
NEXT STEPS
  • Research common phrases used in cryptographic examples for Hill Cipher.
  • Learn about statistical analysis techniques in cryptanalysis.
  • Explore the implications of modulo operations in cipher encoding.
  • Study existing tools for automating Hill Cipher cracking.
USEFUL FOR

Cryptography enthusiasts, students studying cryptanalysis, and anyone interested in understanding the Hill Cipher and its vulnerabilities.

J6204
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Homework Statement



I've created code to crack a Hill Cipher (n=3).
I'm unsure which cribs to try to crack a specific code.
Would anyone mind posting ideas? The crib must be 9 letters in length.

Homework Equations

The Attempt at a Solution

 

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J6204 said:
I've created code to crack a Hill Cipher
Or have you only created code to encrypt and decrypt using the Hill Cipher, given the key? Cracking a code involves cryptanalysis, which identifies the type of cipher employed, then applies statistical tests to identify the probably key, language and message content.

A crib will require knowledge of the sender or situation. What do you know about the source? Do you have any idea of phrases that may have been enciphered in that example? A restriction to only letters, say modulo 26, would mean that numbers must be spelled out in full. If this was an academic exercise then you need to guess at the key or text likely to be chosen for the demonstration. I would start with something as obvious as; “hillcipher”; which unfortunately, has too many letters.

Does the full stop indicate the use of modulo 27?
Please post the full encicode as an ascii.txt file rather than a blur.png
or can you give us a link to this example on the web?
 
Last edited:

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