2021/2021-challenge5.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.column_transposition import *
  21 from szyfrow.railfence import *
  22 from szyfrow.support.text_prettify import *
  23
  24 import numpy as np
  25 import pandas as pd
  26 import matplotlib.pyplot as plt
  27
  28 import collections
  29 %matplotlib inline
  30 ```
  31
  32 ```python Collapsed="false"
  33 challenge_number = 5
  34 plaintext_a_filename = f'plaintext.{challenge_number}a.txt'
  35 plaintext_b_filename = f'plaintext.{challenge_number}b.txt'
  36 ciphertext_a_filename = f'ciphertext.{challenge_number}a.txt'
  37 ciphertext_b_filename = f'ciphertext.{challenge_number}b.txt'
  38 ```
  39
  40 ```python Collapsed="false"
  41 ca = open(ciphertext_a_filename).read()
  42 cb = open(ciphertext_b_filename).read()
  43
  44 sca = sanitise(ca)
  45 rsca = cat(reversed(sca))
  46 scb = sanitise(cb)
  47 ```
  48
  49 ```python
  50 sca_counts = collections.Counter(sca)
  51 sca_counts
  52 ```
  53
  54 ```python
  55 pd.Series(sca_counts).sort_index().plot.bar()
  56 ```
  57
  58 ```python
  59 key_a, score_a = railfence_break(sca, fitness=Ptrigrams)
  60 print(key_a, '\n')
  61 pa = railfence_decipher(sca, key_a)
  62 print(pa)
  63 ```
  64
  65 ```python
  66 (word_a, fill_a, empty_a), score_a = column_transposition_break(rsca, fitness=Ptrigrams)
  67 print(word_a, fill_a, empty_a, '\n')
  68 pa = column_transposition_decipher(rsca, word_a, fillcolumnwise=fill_a, emptycolumnwise=empty_a)
  69 print(pa)
  70 ```
  71
  72 ```python
  73 (word_a, wrap_a), score_a = keyword_break(sca, fitness=Pletters)
  74 print(word_a, wrap_a, '\n')
  75 pa = keyword_decipher(sca, word_a, wrap_a)
  76 print(pa)
  77 ```
  78
  79 ```python
  80 word_a, score_a = monoalphabetic_sa_break(sca)
  81 print(word_a, '\n')
  82 pa = keyword_decipher(sca, word_a)
  83 print(pa)
  84 ```
  85
  86 ```python
  87 word_a, score_a = vigenere_frequency_break(sca, fitness=Ptrigrams)
  88 print(word_a, '\n')
  89 pa = vigenere_decipher(sca, word_a)
  90 print(pa)
  91 ```
  92
  93 ```python
  94 pa = railfence_decipher(sca, key_a)
  95 print(prettify(pa))
  96 ```
  97
  98 ```python Collapsed="false"
  99 open(plaintext_a_filename, 'w').write(prettify(pa))
 100 ```
 101
 102 ```python
 103 morse_chars = 'a b c d e f g h i j k l m n o p q r s t u v w x y z 0 1 2 3 4 5 6 7 8 9'.split()
 104 # morse_chars
 105 ```
 106
 107 ```python
 108 morse_codes = '.- / -... / -.-. / -.. / . / ..-. / --. / .... / .. / .--- / -.- / .-.. / -- / -. / --- / .--. / --.- / .-. / ... / - / ..- / ...- / .-- / -..- / -.-- / --.. / ----- / .---- / ..--- / ...-- / ....- / ..... / -.... / --... / ---.. / ----.'.split(' / ')
 109 ```
 110
 111 ```python
 112 char_to_morse = {l: c for l, c in zip(morse_chars, morse_codes)}
 113 morse_to_char = {c: l for l, c in zip(morse_chars, morse_codes)}
 114 [char_to_morse[l] for l in 'abc']
 115 ```
 116
 117 ```python
 118 morse_table = ''.maketrans('AD', '.-')
 119 cb_dd = cb.translate(morse_table)
 120 cb_words = cb_dd.split(' / ')
 121 cb_letters = cat(cat(morse_to_char[l] for l in w.split()) for w in cb_words)
 122 cb_letters
 123 ```
 124
 125 ```python
 126 word_b, score_b = vigenere_frequency_break(cb_letters, fitness=Ptrigrams)
 127 print(word_b, '\n')
 128 pb = vigenere_decipher(cb_letters, word_b)
 129 print(pb)
 130 ```
 131
 132 ```python
 133 pb = vigenere_decipher(cb_letters, word_b)
 134 print(prettify(pb))
 135 ```
 136
 137 ```python Collapsed="false"
 138 open(plaintext_b_filename, 'w').write(prettify(pb))
 139 ```
 140
 141 ```python Collapsed="false"
 142
 143 ```