2020-early/2020-a-challenge2.md

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  11     display_name: Python 3
  12     language: python
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  14 ---
  15
  16 ```python
  17 import os,sys,inspect
  18 currentdir = os.path.dirname(os.path.abspath(inspect.getfile(inspect.currentframe())))
  19 parentdir = os.path.dirname(currentdir)
  20 sys.path.insert(0,parentdir)
  21 ```
  22
  23 ```python
  24 from cipher.caesar import *
  25 from cipher.affine import *
  26
  27 from support.text_prettify import *
  28 from support.utilities import *
  29 from support.plot_frequency_histogram import *
  30 ```
  31
  32 ```python
  33 challenge_number = 2
  34 plaintext_a_filename = f'{challenge_number}a.plaintext'
  35 plaintext_b_filename = f'{challenge_number}b.plaintext'
  36 ciphertext_a_filename = f'{challenge_number}a.ciphertext'
  37 ciphertext_b_filename = f'{challenge_number}b.ciphertext'
  38 ```
  39
  40 ```python
  41 ca = open(ciphertext_a_filename).read()
  42 cb = open(ciphertext_b_filename).read()
  43
  44 sca = sanitise(ca)
  45 pca = letters(ca)
  46 pta = depunctuate(ca)
  47
  48 scb = sanitise(cb)
  49 pcb = letters(cb)
  50 ptb = depunctuate(cb)
  51 ```
  52
  53 ```python
  54 (ma, ca, za), score_a = affine_break(sca)
  55 print((ma, ca, za), '\n')
  56 pa = repunctuate(affine_decipher(sca, ma, ca, za), pta)
  57 print(pa)
  58 ```
  59
  60 ```python
  61 open(plaintext_a_filename, 'w').write(pa)
  62 ```
  63
  64 ```python
  65 (mb, cb, zb), score_a = affine_break(scb)
  66 print((mb, cb, zb), '\n')
  67 pb = repunctuate(affine_decipher(scb, mb, cb, zb), ptb)
  68 print(pb)
  69 ```
  70
  71 ```python
  72 open(plaintext_b_filename, 'w').write(pb)
  73 ```
  74
  75 ```python
  76
  77 ```