2020/2020-challenge2.md

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  11     display_name: Python 3
  12     language: python
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  14 ---
  15
  16 ```python Collapsed="false"
  17 from szyfrow.affine import *
  18 from szyfrow.keyword_cipher import *
  19 ```
  20
  21 ```python Collapsed="false"
  22 challenge_number = 2
  23 plaintext_a_filename = f'plaintext.{challenge_number}a.txt'
  24 plaintext_b_filename = f'plaintext.{challenge_number}b.txt'
  25 ciphertext_a_filename = f'ciphertext.{challenge_number}a.txt'
  26 ciphertext_b_filename = f'ciphertext.{challenge_number}b.txt'
  27 ```
  28
  29 ```python Collapsed="false"
  30 ca = open(ciphertext_a_filename).read()
  31 cb = open(ciphertext_b_filename).read()
  32 scb = sanitise(cb)
  33 ```
  34
  35 ```python Collapsed="false"
  36 (m_a, a_a, o_a), score_a = affine_break(ca)
  37 print(m_a, a_a, o_a, '\n')
  38 pa = affine_decipher(ca, m_a, a_a, o_a)
  39 print(pa)
  40 ```
  41
  42 ```python Collapsed="false"
  43 open(plaintext_a_filename, 'w').write(pa)
  44 ```
  45
  46 ```python Collapsed="false"
  47 (word_b, wrap_b), score_b = keyword_break_mp(scb, fitness=Ptrigrams)
  48 print(word_b, wrap_b, '\n')
  49 pb = keyword_decipher(cb, word_b, wrap_b)
  50 print(pb)
  51 ```
  52
  53 ```python Collapsed="false"
  54 word_b, score_b = simulated_annealing_break(scb)
  55 print(word_b, '\n')
  56 pb = keyword_decipher(cb, word_b)
  57 print(pb)
  58 ```
  59
  60 ```python Collapsed="false"
  61 keyword_decipher(cb, 'abwehr', KeywordWrapAlphabet.from_last)
  62 ```
  63
  64 ```python Collapsed="false"
  65 open(plaintext_b_filename, 'w').write(pb)
  66 ```
  67
  68 ```python Collapsed="false"
  69
  70 ```