5 from itertools
import zip_longest
, cycle
, chain
6 from language_models
import *
8 logger
= logging
.getLogger(__name__
)
9 logger
.addHandler(logging
.FileHandler('cipher.log'))
10 logger
.setLevel(logging
.WARNING
)
11 #logger.setLevel(logging.INFO)
12 #logger.setLevel(logging.DEBUG)
15 modular_division_table
= [[0]*26 for _
in range(26)]
19 modular_division_table
[b
][c
] = a
22 def every_nth(text
, n
, fillvalue
=''):
23 """Returns n strings, each of which consists of every nth character,
24 starting with the 0th, 1st, 2nd, ... (n-1)th character
26 >>> every_nth(string.ascii_lowercase, 5)
27 ['afkpuz', 'bglqv', 'chmrw', 'dinsx', 'ejoty']
28 >>> every_nth(string.ascii_lowercase, 1)
29 ['abcdefghijklmnopqrstuvwxyz']
30 >>> every_nth(string.ascii_lowercase, 26) # doctest: +NORMALIZE_WHITESPACE
31 ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
32 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']
33 >>> every_nth(string.ascii_lowercase, 5, fillvalue='!')
34 ['afkpuz', 'bglqv!', 'chmrw!', 'dinsx!', 'ejoty!']
36 split_text
= [text
[i
:i
+n
] for i
in range(0, len(text
), n
)]
37 return [''.join(l
) for l
in zip_longest(*split_text
, fillvalue
=fillvalue
)]
39 def combine_every_nth(split_text
):
40 """Reforms a text split into every_nth strings
42 >>> combine_every_nth(every_nth(string.ascii_lowercase, 5))
43 'abcdefghijklmnopqrstuvwxyz'
44 >>> combine_every_nth(every_nth(string.ascii_lowercase, 1))
45 'abcdefghijklmnopqrstuvwxyz'
46 >>> combine_every_nth(every_nth(string.ascii_lowercase, 26))
47 'abcdefghijklmnopqrstuvwxyz'
49 return ''.join([''.join(l
)
50 for l
in zip_longest(*split_text
, fillvalue
='')])
52 def chunks(text
, n
, fillvalue
=None):
53 """Split a text into chunks of n characters
55 >>> chunks('abcdefghi', 3)
57 >>> chunks('abcdefghi', 4)
59 >>> chunks('abcdefghi', 4, fillvalue='!')
60 ['abcd', 'efgh', 'i!!!']
63 padding
= fillvalue
[0] * (n
- len(text
) % n
)
66 return [(text
+padding
)[i
:i
+n
] for i
in range(0, len(text
), n
)]
68 def transpose(items
, transposition
):
69 """Moves items around according to the given transposition
71 >>> transpose(['a', 'b', 'c', 'd'], (0,1,2,3))
73 >>> transpose(['a', 'b', 'c', 'd'], (3,1,2,0))
75 >>> transpose([10,11,12,13,14,15], (3,2,4,1,5,0))
76 [13, 12, 14, 11, 15, 10]
78 transposed
= [''] * len(transposition
)
79 for p
, t
in enumerate(transposition
):
80 transposed
[p
] = items
[t
]
83 def untranspose(items
, transposition
):
86 >>> untranspose(['a', 'b', 'c', 'd'], [0,1,2,3])
88 >>> untranspose(['d', 'b', 'c', 'a'], [3,1,2,0])
90 >>> untranspose([13, 12, 14, 11, 15, 10], [3,2,4,1,5,0])
91 [10, 11, 12, 13, 14, 15]
93 transposed
= [''] * len(transposition
)
94 for p
, t
in enumerate(transposition
):
95 transposed
[t
] = items
[p
]
98 def deduplicate(text
):
99 return list(collections
.OrderedDict
.fromkeys(text
))
102 def caesar_encipher_letter(accented_letter
, shift
):
103 """Encipher a letter, given a shift amount
105 >>> caesar_encipher_letter('a', 1)
107 >>> caesar_encipher_letter('a', 2)
109 >>> caesar_encipher_letter('b', 2)
111 >>> caesar_encipher_letter('x', 2)
113 >>> caesar_encipher_letter('y', 2)
115 >>> caesar_encipher_letter('z', 2)
117 >>> caesar_encipher_letter('z', -1)
119 >>> caesar_encipher_letter('a', -1)
121 >>> caesar_encipher_letter('A', 1)
123 >>> caesar_encipher_letter('é', 1)
126 letter
= unaccent(accented_letter
)
127 if letter
in string
.ascii_letters
:
128 if letter
in string
.ascii_uppercase
:
129 alphabet_start
= ord('A')
131 alphabet_start
= ord('a')
132 return chr(((ord(letter
) - alphabet_start
+ shift
) % 26) +
137 def caesar_decipher_letter(letter
, shift
):
138 """Decipher a letter, given a shift amount
140 >>> caesar_decipher_letter('b', 1)
142 >>> caesar_decipher_letter('b', 2)
145 return caesar_encipher_letter(letter
, -shift
)
147 def caesar_encipher(message
, shift
):
148 """Encipher a message with the Caesar cipher of given shift
150 >>> caesar_encipher('abc', 1)
152 >>> caesar_encipher('abc', 2)
154 >>> caesar_encipher('abcxyz', 2)
156 >>> caesar_encipher('ab cx yz', 2)
158 >>> caesar_encipher('Héllo World!', 2)
161 enciphered
= [caesar_encipher_letter(l
, shift
) for l
in message
]
162 return ''.join(enciphered
)
164 def caesar_decipher(message
, shift
):
165 """Decipher a message with the Caesar cipher of given shift
167 >>> caesar_decipher('bcd', 1)
169 >>> caesar_decipher('cde', 2)
171 >>> caesar_decipher('cd ez ab', 2)
173 >>> caesar_decipher('Jgnnq Yqtnf!', 2)
176 return caesar_encipher(message
, -shift
)
178 def affine_encipher_letter(accented_letter
, multiplier
=1, adder
=0, one_based
=True):
179 """Encipher a letter, given a multiplier and adder
181 >>> ''.join([affine_encipher_letter(l, 3, 5, True) \
182 for l in string.ascii_uppercase])
183 'HKNQTWZCFILORUXADGJMPSVYBE'
184 >>> ''.join([affine_encipher_letter(l, 3, 5, False) \
185 for l in string.ascii_uppercase])
186 'FILORUXADGJMPSVYBEHKNQTWZC'
188 letter
= unaccent(accented_letter
)
189 if letter
in string
.ascii_letters
:
190 if letter
in string
.ascii_uppercase
:
191 alphabet_start
= ord('A')
193 alphabet_start
= ord('a')
194 letter_number
= ord(letter
) - alphabet_start
195 if one_based
: letter_number
+= 1
196 cipher_number
= (letter_number
* multiplier
+ adder
) % 26
197 if one_based
: cipher_number
-= 1
198 return chr(cipher_number
% 26 + alphabet_start
)
202 def affine_decipher_letter(letter
, multiplier
=1, adder
=0, one_based
=True):
203 """Encipher a letter, given a multiplier and adder
205 >>> ''.join([affine_decipher_letter(l, 3, 5, True) \
206 for l in 'HKNQTWZCFILORUXADGJMPSVYBE'])
207 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
208 >>> ''.join([affine_decipher_letter(l, 3, 5, False) \
209 for l in 'FILORUXADGJMPSVYBEHKNQTWZC'])
210 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
212 if letter
in string
.ascii_letters
:
213 if letter
in string
.ascii_uppercase
:
214 alphabet_start
= ord('A')
216 alphabet_start
= ord('a')
217 cipher_number
= ord(letter
) - alphabet_start
218 if one_based
: cipher_number
+= 1
220 modular_division_table
[multiplier
]
221 [(cipher_number
- adder
) % 26] )
222 if one_based
: plaintext_number
-= 1
223 return chr(plaintext_number
% 26 + alphabet_start
)
227 def affine_encipher(message
, multiplier
=1, adder
=0, one_based
=True):
228 """Encipher a message
230 >>> affine_encipher('hours passed during which jerico tried every ' \
231 'trick he could think of', 15, 22, True)
232 'lmyfu bkuusd dyfaxw claol psfaom jfasd snsfg jfaoe ls omytd jlaxe mh'
234 enciphered
= [affine_encipher_letter(l
, multiplier
, adder
, one_based
)
236 return ''.join(enciphered
)
238 def affine_decipher(message
, multiplier
=1, adder
=0, one_based
=True):
239 """Decipher a message
241 >>> affine_decipher('lmyfu bkuusd dyfaxw claol psfaom jfasd snsfg ' \
242 'jfaoe ls omytd jlaxe mh', 15, 22, True)
243 'hours passed during which jerico tried every trick he could think of'
245 enciphered
= [affine_decipher_letter(l
, multiplier
, adder
, one_based
)
247 return ''.join(enciphered
)
250 def keyword_cipher_alphabet_of(keyword
, wrap_alphabet
=0):
251 """Find the cipher alphabet given a keyword.
252 wrap_alphabet controls how the rest of the alphabet is added
255 1 : from the last letter in the sanitised keyword
256 2 : from the largest letter in the sanitised keyword
258 >>> keyword_cipher_alphabet_of('bayes')
259 'bayescdfghijklmnopqrtuvwxz'
260 >>> keyword_cipher_alphabet_of('bayes', 0)
261 'bayescdfghijklmnopqrtuvwxz'
262 >>> keyword_cipher_alphabet_of('bayes', 1)
263 'bayestuvwxzcdfghijklmnopqr'
264 >>> keyword_cipher_alphabet_of('bayes', 2)
265 'bayeszcdfghijklmnopqrtuvwx'
267 if wrap_alphabet
== 0:
268 cipher_alphabet
= ''.join(deduplicate(sanitise(keyword
) +
269 string
.ascii_lowercase
))
271 if wrap_alphabet
== 1:
272 last_keyword_letter
= deduplicate(sanitise(keyword
))[-1]
274 last_keyword_letter
= sorted(sanitise(keyword
))[-1]
275 last_keyword_position
= string
.ascii_lowercase
.find(
276 last_keyword_letter
) + 1
277 cipher_alphabet
= ''.join(
278 deduplicate(sanitise(keyword
) +
279 string
.ascii_lowercase
[last_keyword_position
:] +
280 string
.ascii_lowercase
))
281 return cipher_alphabet
284 def keyword_encipher(message
, keyword
, wrap_alphabet
=0):
285 """Enciphers a message with a keyword substitution cipher.
286 wrap_alphabet controls how the rest of the alphabet is added
289 1 : from the last letter in the sanitised keyword
290 2 : from the largest letter in the sanitised keyword
292 >>> keyword_encipher('test message', 'bayes')
294 >>> keyword_encipher('test message', 'bayes', 0)
296 >>> keyword_encipher('test message', 'bayes', 1)
298 >>> keyword_encipher('test message', 'bayes', 2)
301 cipher_alphabet
= keyword_cipher_alphabet_of(keyword
, wrap_alphabet
)
302 cipher_translation
= ''.maketrans(string
.ascii_lowercase
, cipher_alphabet
)
303 return unaccent(message
).lower().translate(cipher_translation
)
305 def keyword_decipher(message
, keyword
, wrap_alphabet
=0):
306 """Deciphers a message with a keyword substitution cipher.
307 wrap_alphabet controls how the rest of the alphabet is added
310 1 : from the last letter in the sanitised keyword
311 2 : from the largest letter in the sanitised keyword
313 >>> keyword_decipher('rsqr ksqqbds', 'bayes')
315 >>> keyword_decipher('rsqr ksqqbds', 'bayes', 0)
317 >>> keyword_decipher('lskl dskkbus', 'bayes', 1)
319 >>> keyword_decipher('qspq jsppbcs', 'bayes', 2)
322 cipher_alphabet
= keyword_cipher_alphabet_of(keyword
, wrap_alphabet
)
323 cipher_translation
= ''.maketrans(cipher_alphabet
, string
.ascii_lowercase
)
324 return message
.lower().translate(cipher_translation
)
327 def vigenere_encipher(message
, keyword
):
330 >>> vigenere_encipher('hello', 'abc')
333 shifts
= [ord(l
) - ord('a') for l
in sanitise(keyword
)]
334 pairs
= zip(message
, cycle(shifts
))
335 return ''.join([caesar_encipher_letter(l
, k
) for l
, k
in pairs
])
337 def vigenere_decipher(message
, keyword
):
340 >>> vigenere_decipher('hfnlp', 'abc')
343 shifts
= [ord(l
) - ord('a') for l
in sanitise(keyword
)]
344 pairs
= zip(message
, cycle(shifts
))
345 return ''.join([caesar_decipher_letter(l
, k
) for l
, k
in pairs
])
347 beaufort_encipher
=vigenere_decipher
348 beaufort_decipher
=vigenere_encipher
351 def transpositions_of(keyword
):
352 """Finds the transpostions given by a keyword. For instance, the keyword
353 'clever' rearranges to 'celrv', so the first column (0) stays first, the
354 second column (1) moves to third, the third column (2) moves to second,
357 If passed a tuple, assume it's already a transposition and just return it.
359 >>> transpositions_of('clever')
361 >>> transpositions_of('fred')
363 >>> transpositions_of((3, 2, 0, 1))
366 if isinstance(keyword
, tuple):
369 key
= deduplicate(keyword
)
370 transpositions
= tuple(key
.index(l
) for l
in sorted(key
))
371 return transpositions
373 def pad(message_len
, group_len
, fillvalue
):
374 padding_length
= group_len
- message_len
% group_len
375 if padding_length
== group_len
: padding_length
= 0
377 for i
in range(padding_length
):
378 if callable(fillvalue
):
379 padding
+= fillvalue()
384 def column_transposition_encipher(message
, keyword
, fillvalue
=' ',
385 fillcolumnwise
=False,
386 emptycolumnwise
=False):
387 """Enciphers using the column transposition cipher.
388 Message is padded to allow all rows to be the same length.
390 >>> column_transposition_encipher('hellothere', 'abcdef', fillcolumnwise=True)
392 >>> column_transposition_encipher('hellothere', 'abcdef', fillcolumnwise=True, emptycolumnwise=True)
394 >>> column_transposition_encipher('hellothere', 'abcdef')
396 >>> column_transposition_encipher('hellothere', 'abcde')
398 >>> column_transposition_encipher('hellothere', 'abcde', fillcolumnwise=True, emptycolumnwise=True)
400 >>> column_transposition_encipher('hellothere', 'abcde', fillcolumnwise=True, emptycolumnwise=False)
402 >>> column_transposition_encipher('hellothere', 'abcde', fillcolumnwise=False, emptycolumnwise=True)
404 >>> column_transposition_encipher('hellothere', 'abcde', fillcolumnwise=False, emptycolumnwise=False)
406 >>> column_transposition_encipher('hellothere', 'clever', fillcolumnwise=True, emptycolumnwise=True)
408 >>> column_transposition_encipher('hellothere', 'clever', fillcolumnwise=True, emptycolumnwise=False)
410 >>> column_transposition_encipher('hellothere', 'clever', fillcolumnwise=False, emptycolumnwise=True)
412 >>> column_transposition_encipher('hellothere', 'clever', fillcolumnwise=False, emptycolumnwise=False)
414 >>> column_transposition_encipher('hellothere', 'cleverly')
416 >>> column_transposition_encipher('hellothere', 'cleverly', fillvalue='!')
418 >>> column_transposition_encipher('hellothere', 'cleverly', fillvalue=lambda: '*')
421 transpositions
= transpositions_of(keyword
)
422 message
+= pad(len(message
), len(transpositions
), fillvalue
)
424 rows
= every_nth(message
, len(message
) // len(transpositions
))
426 rows
= chunks(message
, len(transpositions
))
427 transposed
= [transpose(r
, transpositions
) for r
in rows
]
429 return combine_every_nth(transposed
)
431 return ''.join(chain(*transposed
))
433 def column_transposition_decipher(message
, keyword
, fillvalue
=' ',
434 fillcolumnwise
=False,
435 emptycolumnwise
=False):
436 """Deciphers using the column transposition cipher.
437 Message is padded to allow all rows to be the same length.
439 >>> column_transposition_decipher('hellothere', 'abcde', fillcolumnwise=True, emptycolumnwise=True)
441 >>> column_transposition_decipher('hlohreltee', 'abcde', fillcolumnwise=True, emptycolumnwise=False)
443 >>> column_transposition_decipher('htehlelroe', 'abcde', fillcolumnwise=False, emptycolumnwise=True)
445 >>> column_transposition_decipher('hellothere', 'abcde', fillcolumnwise=False, emptycolumnwise=False)
447 >>> column_transposition_decipher('heotllrehe', 'clever', fillcolumnwise=True, emptycolumnwise=True)
449 >>> column_transposition_decipher('holrhetlee', 'clever', fillcolumnwise=True, emptycolumnwise=False)
451 >>> column_transposition_decipher('htleehoelr', 'clever', fillcolumnwise=False, emptycolumnwise=True)
453 >>> column_transposition_decipher('hleolteher', 'clever', fillcolumnwise=False, emptycolumnwise=False)
456 transpositions
= transpositions_of(keyword
)
457 message
+= pad(len(message
), len(transpositions
), '*')
459 rows
= every_nth(message
, len(message
) // len(transpositions
))
461 rows
= chunks(message
, len(transpositions
))
462 untransposed
= [untranspose(r
, transpositions
) for r
in rows
]
464 return combine_every_nth(untransposed
)
466 return ''.join(chain(*untransposed
))
468 def scytale_encipher(message
, rows
, fillvalue
=' '):
469 """Enciphers using the scytale transposition cipher.
470 Message is padded with spaces to allow all rows to be the same length.
472 >>> scytale_encipher('thequickbrownfox', 3)
474 >>> scytale_encipher('thequickbrownfox', 4)
476 >>> scytale_encipher('thequickbrownfox', 5)
478 >>> scytale_encipher('thequickbrownfox', 6)
480 >>> scytale_encipher('thequickbrownfox', 7)
483 transpositions
= [i
for i
in range(math
.ceil(len(message
) / rows
))]
484 return column_transposition_encipher(message
, transpositions
,
485 fillcolumnwise
=False, emptycolumnwise
=True)
487 def scytale_decipher(message
, rows
):
488 """Deciphers using the scytale transposition cipher.
489 Assumes the message is padded so that all rows are the same length.
491 >>> scytale_decipher('tcnhkfeboqrxuo iw ', 3)
493 >>> scytale_decipher('tubnhirfecooqkwx', 4)
495 >>> scytale_decipher('tubnhirfecooqkwx', 5)
497 >>> scytale_decipher('tqcrnxhukof eibwo ', 6)
499 >>> scytale_decipher('tqcrnxhukof eibwo ', 7)
502 transpositions
= [i
for i
in range(math
.ceil(len(message
) / rows
))]
503 return column_transposition_decipher(message
, transpositions
,
504 fillcolumnwise
=False, emptycolumnwise
=True)
507 if __name__
== "__main__":