2020/2020-challenge5.md

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  11     display_name: Python 3
  12     language: python
  13     name: python3
  14 ---
  15
  16 ```python Collapsed="false"
  17 from szyfrow.keyword_cipher import *
  18 from szyfrow.column_transposition import *
  19 from szyfrow.support.text_prettify import *
  20 ```
  21
  22 ```python Collapsed="false"
  23 challenge_number = 5
  24 plaintext_a_filename = f'plaintext.{challenge_number}a.txt'
  25 plaintext_b_filename = f'plaintext.{challenge_number}b.txt'
  26 ciphertext_a_filename = f'ciphertext.{challenge_number}a.txt'
  27 ciphertext_b_filename = f'ciphertext.{challenge_number}b.txt'
  28 ```
  29
  30 ```python Collapsed="false"
  31 ca = open(ciphertext_a_filename).read()
  32 sca = sanitise(ca)
  33 cb = open(ciphertext_b_filename).read()
  34 scb = sanitise(cb)
  35 ```
  36
  37 ```python Collapsed="false"
  38 (word_a, wrap_a), score_a = keyword_break_mp(sca, fitness=Ptrigrams)
  39 print(word_a, wrap_a, '\n')
  40 pa = keyword_decipher(ca, word_a, wrap_a)
  41 print(pa)
  42 ```
  43
  44 ```python Collapsed="false"
  45 keyword_decipher(ca, 'akela', wrap_a)
  46 ```
  47
  48 ```python Collapsed="false"
  49 word_a, score_a = simulated_annealing_break(sca, fitness=Ptrigrams,
  50         plain_alphabet=string.ascii_lowercase, cipher_alphabet=keyword_cipher_alphabet_of('akkad', wrap_alphabet=KeywordWrapAlphabet.from_largest))
  51 print(word_a, '\n')
  52 pa = keyword_decipher(ca, word_a)
  53 print(pa)
  54 ```
  55
  56 ```python Collapsed="false"
  57 pa = prettify(keyword_decipher(sca, 'akela', wrap_alphabet=KeywordWrapAlphabet.from_a))
  58 print(pa)
  59 ```
  60
  61 ```python Collapsed="false"
  62 open(plaintext_a_filename, 'w').write(pa)
  63 ```
  64
  65 ```python Collapsed="false"
  66 (word_b, wrap_b), score_b = keyword_break_mp(scb, fitness=Ptrigrams)
  67 print(word_b, wrap_b, '\n')
  68 pb = keyword_decipher(cb, word_b, wrap_b)
  69 print(pb)
  70 ```
  71
  72 ```python Collapsed="false"
  73 pb = prettify(keyword_decipher(scb, word_b, wrap_b))
  74 print(pb)
  75 ```
  76
  77 ```python Collapsed="false"
  78 open(plaintext_b_filename, 'w').write(pb)
  79 ```
  80
  81 ```python Collapsed="false"
  82 pb = """dear uncle wilhelm as you promised we thoroughly enjoyed our visit to your cousin in lincoln and
  83 found it most informative stop the beautiful cathedral almost justified our visit on its own and our
  84 hosts shared with us some interesting drawings of the towers you mentioned stop they graciously
  85 allowed me to copy the sketches and explained much about how the towers are built and why stop as
  86 usual i will send you my notes and sketches via our dear friend jessica who has promised to ensure
  87 their safe delivery stop really i must congratulate our hosts in the local scout groups for the
  88 marvellous way in which they have organised our travel though some of the scouts have been rather
  89 more solicitous than we had expected asking rather a lot of questions about our plans stop generally
  90 i hope they were satisfied with the answers that we gave but we feel that we are at risk of
  91 overstaying our welcome so we will return to london on tuesday stop even though we have enjoyed our
  92 time together there has been some debate among the group about where we should visit next stop there
  93 are so many interesting sites to visit along the majestic thames estuary so we have decided to split
  94 into two groups stop ralf will lead one party on a tour of the kent coast while i am very much
  95 looking forward to exploring the essex marshes stop do let me know if you have a better idea but i
  96 have been told that canewdons fifteenth century church affords an elevation with a wide view of
  97 the surrounding lands in this otherwise rather flat landscape and is the site of another fascinating
  98 tower which i will be certain to sketch for you stop finally if you have any further requests for
  99 specific information then perhaps you could leave a message for me at the post office there stop karl
 100 message ends"""
 101 ```
 102
 103 ```python Collapsed="false"
 104 spb = sanitise(pb)
 105 ```
 106
 107 ```python Collapsed="false"
 108 pbs = pb.split()
 109 [pbs[i+1] for i, w in enumerate(pbs) if w == 'stop']
 110 ```
 111
 112 ```python Collapsed="false"
 113 pbs = pb.split()
 114 cat(pbs[i+1][0] for i, w in enumerate(pbs) if w == 'stop')
 115 ```
 116
 117 ```python Collapsed="false"
 118 wcat(segment(cat(w[0] for w in pbs)))
 119 ```
 120
 121 ```python Collapsed="false"
 122 wcat(segment(cat(w[1] for w in pbs if len(w) > 1)))
 123 ```
 124
 125 ```python Collapsed="false"
 126 wcat(segment(cat(w[-1] for w in reversed(pbs))))
 127 ```
 128
 129 ```python Collapsed="false"
 130 max([len(w) for w in pbs])
 131 ```
 132
 133 ```python Collapsed="false"
 134 [len(s.strip().split()) for s in pb.split('stop')]
 135 ```
 136
 137 ```python Collapsed="false"
 138 tt = ''.maketrans('rdf', 'RDF')
 139 pbcap = wcat(pb.split()).translate(tt)
 140 spbcap = wcat(spb.split()).translate(tt)
 141 pbcap
 142 ```
 143
 144 ```python Collapsed="false"
 145 pbcap2 = cat(('\n' + c) if c.isupper() else c for c in pbcap)
 146 print(pbcap2)
 147 ```
 148
 149 ```python Collapsed="false"
 150 wcat(chunks(spb, 5))
 151 ```
 152
 153 ```python Collapsed="false"
 154 cat(w[-1] for w in chunks(spb, 5))
 155 ```
 156
 157 ```python Collapsed="false"
 158 locR = [i for i, c in enumerate(spb) if c == 'r']
 159 locD = [i for i, c in enumerate(spb) if c == 'd']
 160 locF = [i for i, c in enumerate(spb) if c == 'f']
 161 len(locR), len(locD), len(locF)
 162 ```
 163
 164 ```python Collapsed="false"
 165 triples = []
 166 for r in locR:
 167     for d in locD:
 168         for f in locF:
 169             if d > r:
 170                 if d - r == f - d:
 171                     triples += [(r, d, f, d - r)]
 172 triples
 173 ```
 174
 175 ```python Collapsed="false"
 176 t = cat(c if c.isupper() else '.' for c in pbscap)
 177 col = 305 % 32
 178 tcs = chunks(spb, 32)
 179 stcs = [wcat([c[:col], c[col], c[col+1:]]) for c in tcs]
 180 print(lcat(stcs))
 181 ```
 182
 183 ```python Collapsed="false"
 184 results = []
 185 for l in range(1, 40):
 186     for i in range(l):
 187         cs = chunks(spb, l, fillvalue=' ')
 188         t = cat(c[i] for c in cs)
 189         f = Ptrigrams(t)
 190         results += [{'l': l, 'i': i, 't': t, 'f': f * l}]
 191 len(results)
 192 ```
 193
 194 ```python Collapsed="false"
 195 list(sorted(results, key=lambda r: r['f']))[-4:]
 196 ```
 197
 198 ```python Collapsed="false"
 199 rdfresults = [r for r in results if 'rdf' in r['t']]
 200 len(rdfresults)
 201 ```
 202
 203 ```python Collapsed="false"
 204 rdfresults
 205 ```
 206
 207 ```python Collapsed="false"
 208
 209 ```