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 wcat(segment(cat(w[0] for w in pbs)))
 114 ```
 115
 116 ```python Collapsed="false"
 117 wcat(segment(cat(w[1] for w in pbs if len(w) > 1)))
 118 ```
 119
 120 ```python Collapsed="false"
 121 wcat(segment(cat(w[-1] for w in reversed(pbs))))
 122 ```
 123
 124 ```python Collapsed="false"
 125 max([len(w) for w in pbs])
 126 ```
 127
 128 ```python Collapsed="false"
 129 [len(s.strip().split()) for s in pb.split('stop')]
 130 ```
 131
 132 ```python Collapsed="false"
 133 tt = ''.maketrans('rdf', 'RDF')
 134 pbcap = wcat(pb.split()).translate(tt)
 135 spbcap = wcat(spb.split()).translate(tt)
 136 pbcap
 137 ```
 138
 139 ```python Collapsed="false"
 140 pbcap2 = cat(('\n' + c) if c.isupper() else c for c in pbcap)
 141 print(pbcap2)
 142 ```
 143
 144 ```python Collapsed="false"
 145 wcat(chunks(spb, 5))
 146 ```
 147
 148 ```python Collapsed="false"
 149 cat(w[-1] for w in chunks(spb, 5))
 150 ```
 151
 152 ```python Collapsed="false"
 153 locR = [i for i, c in enumerate(spb) if c == 'r']
 154 locD = [i for i, c in enumerate(spb) if c == 'd']
 155 locF = [i for i, c in enumerate(spb) if c == 'f']
 156 len(locR), len(locD), len(locF)
 157 ```
 158
 159 ```python Collapsed="false"
 160 triples = []
 161 for r in locR:
 162     for d in locD:
 163         for f in locF:
 164             if d > r:
 165                 if d - r == f - d:
 166                     triples += [(r, d, f, d - r)]
 167 triples
 168 ```
 169
 170 ```python Collapsed="false"
 171 t = cat(c if c.isupper() else '.' for c in pbscap)
 172 col = 305 % 32
 173 tcs = chunks(spb, 32)
 174 stcs = [wcat([c[:col], c[col], c[col+1:]]) for c in tcs]
 175 print(lcat(stcs))
 176 ```
 177
 178 ```python Collapsed="false"
 179 results = []
 180 for l in range(1, 40):
 181     for i in range(l):
 182         cs = chunks(spb, l, fillvalue=' ')
 183         t = cat(c[i] for c in cs)
 184         f = Ptrigrams(t)
 185         results += [{'l': l, 'i': i, 't': t, 'f': f * l}]
 186 len(results)
 187 ```
 188
 189 ```python Collapsed="false"
 190 list(sorted(results, key=lambda r: r['f']))[-4:]
 191 ```
 192
 193 ```python Collapsed="false"
 194 rdfresults = [r for r in results if 'rdf' in r['t']]
 195 len(rdfresults)
 196 ```
 197
 198 ```python Collapsed="false"
 199 rdfresults
 200 ```
 201
 202 ```python Collapsed="false"
 203
 204 ```