2020-early/2020-a-challenge3.md

   1 ---
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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 from cipher.keyword_cipher import *
  27
  28 from support.text_prettify import *
  29 from support.utilities import *
  30 from support.plot_frequency_histogram import *
  31 ```
  32
  33 ```python
  34 challenge_number = 3
  35 plaintext_a_filename = f'{challenge_number}a.plaintext'
  36 plaintext_b_filename = f'{challenge_number}b.plaintext'
  37 ciphertext_a_filename = f'{challenge_number}a.ciphertext'
  38 ciphertext_b_filename = f'{challenge_number}b.ciphertext'
  39 ```
  40
  41 ```python
  42 ca = open(ciphertext_a_filename).read()
  43 cb = open(ciphertext_b_filename).read()
  44
  45 sca = sanitise(ca)
  46 pca = letters(ca)
  47 pta = depunctuate(ca)
  48
  49 scb = sanitise(cb)
  50 pcb = letters(cb)
  51 ptb = depunctuate(cb)
  52 ```
  53
  54 ```python
  55 (kworda, kwrapa), score = keyword_break_mp(sca, fitness=Ptrigrams)
  56 kworda, kwrapa
  57 ```
  58
  59 ```python
  60 pa = keyword_decipher(ca, kworda, kwrapa)
  61 print(pa)
  62 ```
  63
  64 ```python
  65 open(plaintext_a_filename, 'w').write(pa)
  66 ```
  67
  68 ```python
  69 (kwordb, kwrapb), score = keyword_break_mp(scb, fitness=Ptrigrams)
  70 kwordb, kwrapb
  71 ```
  72
  73 ```python
  74 pb = keyword_decipher(cb, kwordb, kwrapb)
  75 print(pb)
  76 ```
  77
  78 ```python
  79 open(plaintext_b_filename, 'w').write(pb)
  80 ```
  81
  82 ```python
  83
  84 ```