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*  Name      :  Afeedh Shaji     
*  Reg. No.  :  B170282CS            
*  Course    :  CS4021D (NTC)      
*  Assgn#    :  1               
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                    Read Me


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*  Problem description
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Implement the following algorithms using SageMath tool

   - Affine cipher
   - Hill cipher
   - Shift cipher
   - Substitution cipher
   - Transposition cipher
   - Vigenere cipher

This should be followed by cryptanalysis of all the above
classical cyphers algorithm from 1 - 6.

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*  Circumstances of programs
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    This program works and runs as intended.

    Implemented the cipher techniques followed by the breaking
    of the ciphers or cryptanalysis including Ciphertext only attack,
    Chosen plaintext attack, Chosen ciphertext attack, Known plaintext
    attack. 

    The program was tested on :
    Python 3.8.5
    SageMath version 9.0


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*  How to build and run the program
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1. Install the dependancies:
        pip install -r requirements.txt

2. Each cipher is written as a script inside a folder with the
   name of the package resembling the cipher technique.

3. Run the sage script runner command inside the
   appropriate cipher folder:
   
        sage <sage_script.sage>

        E.g. sage affine_cipher.sage


Note : There are some redundant code inside each folder (for inst
. ngram_score.py). It is because I haven't found any way to import
as modules in sage and I'm too lazy too find it now >.<