2021/2021-challenge3.md

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  14 ---
  15
  16 ```python Collapsed="false"
  17 from szyfrow.caesar import *
  18 from szyfrow.affine import *
  19 from szyfrow.keyword_cipher import *
  20 from szyfrow.support.text_prettify import *
  21 ```
  22
  23 ```python Collapsed="false"
  24 challenge_number = 3
  25 plaintext_a_filename = f'plaintext.{challenge_number}a.txt'
  26 plaintext_b_filename = f'plaintext.{challenge_number}b.txt'
  27 ciphertext_a_filename = f'ciphertext.{challenge_number}a.txt'
  28 ciphertext_b_filename = f'ciphertext.{challenge_number}b.txt'
  29 ```
  30
  31 ```python Collapsed="false"
  32 ca = open(ciphertext_a_filename).read()
  33 cb = open(ciphertext_b_filename).read()
  34
  35 scb = sanitise(cb)
  36 ```
  37
  38 ```python
  39 (word_a, wrap_a), score_a = keyword_break(ca)
  40 print(word_a, wrap_a, '\n')
  41 pa = keyword_decipher(ca, word_a, wrap_a)
  42 print(pa)
  43 ```
  44
  45 ```python Collapsed="false"
  46 open(plaintext_a_filename, 'w').write(pa)
  47 ```
  48
  49 ```python
  50 (word_b, wrap_b), score_a = keyword_break(scb, fitness=Ptrigrams)
  51 print(word_b, wrap_b, '\n')
  52 pb = keyword_decipher(scb, word_b, wrap_b)
  53 print(prettify(pb))
  54 ```
  55
  56 ```python Collapsed="false"
  57 open(plaintext_b_filename, 'w').write(prettify(pb))
  58 ```
  59
  60 ```python Collapsed="false"
  61
  62 ```