+++ /dev/null
-from utilities import *
-from language_models import *
-import multiprocessing
-
-from keyword_cipher import KeywordWrapAlphabet
-
-from logger import logger
-
-def polybius_grid(keyword, column_order, row_order, letters_to_merge=None,
- wrap_alphabet=KeywordWrapAlphabet.from_a):
- """Grid for a Polybius cipher, using a keyword to rearrange the
- alphabet.
-
-
- >>> polybius_grid('a', 'abcde', 'abcde')['x'] == ('e', 'c')
- True
- >>> polybius_grid('elephant', 'abcde', 'abcde')['e'] == ('a', 'a')
- True
- >>> polybius_grid('elephant', 'abcde', 'abcde')['b'] == ('b', 'c')
- True
- """
- alphabet = keyword_cipher_alphabet_of(keyword, wrap_alphabet=wrap_alphabet)
- if letters_to_merge is None:
- letters_to_merge = {'j': 'i'}
- grid = {l: k
- for k, l in zip([(c, r) for c in column_order for r in row_order],
- [l for l in alphabet if l not in letters_to_merge])}
- for l in letters_to_merge:
- grid[l] = grid[letters_to_merge[l]]
- return grid
-
-def polybius_reverse_grid(keyword, column_order, row_order, letters_to_merge=None,
- wrap_alphabet=KeywordWrapAlphabet.from_a):
- """Grid for decrypting using a Polybius cipher, using a keyword to
- rearrange the alphabet.
-
- >>> polybius_reverse_grid('a', 'abcde', 'abcde')['e', 'c'] == 'x'
- True
- >>> polybius_reverse_grid('elephant', 'abcde', 'abcde')['a', 'a'] == 'e'
- True
- >>> polybius_reverse_grid('elephant', 'abcde', 'abcde')['b', 'c'] == 'b'
- True
- """
- alphabet = keyword_cipher_alphabet_of(keyword, wrap_alphabet=wrap_alphabet)
- if letters_to_merge is None:
- letters_to_merge = {'j': 'i'}
- grid = {k: l
- for k, l in zip([(c, r) for c in column_order for r in row_order],
- [l for l in alphabet if l not in letters_to_merge])}
- return grid
-
-
-def polybius_flatten(pair, column_first):
- """Convert a series of pairs into a single list of characters"""
- if column_first:
- return str(pair[1]) + str(pair[0])
- else:
- return str(pair[0]) + str(pair[1])
-
-def polybius_encipher(message, keyword, column_order, row_order,
- column_first=False,
- letters_to_merge=None, wrap_alphabet=KeywordWrapAlphabet.from_a):
- """Encipher a message with Polybius cipher, using a keyword to rearrange
- the alphabet
-
-
- >>> polybius_encipher('this is a test message for the ' \
- 'polybius decipherment', 'elephant', \
- [1, 2, 3, 4, 5], [1, 2, 3, 4, 5], \
- wrap_alphabet=KeywordWrapAlphabet.from_last)
- '2214445544551522115522511155551543114252542214111352123234442355411135441314115451112122'
- >>> polybius_encipher('this is a test message for the ' \
- 'polybius decipherment', 'elephant', 'abcde', 'abcde', \
- column_first=False)
- 'bbadccddccddaebbaaddbbceaaddddaecbaacadadcbbadaaacdaabedbcccdeddbeaabdccacadaadcceaababb'
- >>> polybius_encipher('this is a test message for the ' \
- 'polybius decipherment', 'elephant', 'abcde', 'abcde', \
- column_first=True)
- 'bbdaccddccddeabbaaddbbecaaddddeabcaaacadcdbbdaaacaadbadecbccedddebaadbcccadaaacdecaaabbb'
- """
- grid = polybius_grid(keyword, column_order, row_order, letters_to_merge, wrap_alphabet)
- return cat(polybius_flatten(grid[l], column_first)
- for l in message
- if l in grid)
-
-
-def polybius_decipher(message, keyword, column_order, row_order,
- column_first=False,
- letters_to_merge=None, wrap_alphabet=KeywordWrapAlphabet.from_a):
- """Decipher a message with a Polybius cipher, using a keyword to rearrange
- the alphabet
-
- >>> polybius_decipher('bbdaccddccddeabbaaddbbecaaddddeabcaaacadcdbbdaaaca'\
- 'adbadecbccedddebaadbcccadaaacdecaaabbb', 'elephant', 'abcde', 'abcde', \
- column_first=False)
- 'toisisvtestxessvbephktoefhnugiysweqifoekxelt'
-
- >>> polybius_decipher('bbdaccddccddeabbaaddbbecaaddddeabcaaacadcdbbdaaaca'\
- 'adbadecbccedddebaadbcccadaaacdecaaabbb', 'elephant', 'abcde', 'abcde', \
- column_first=True)
- 'thisisatestmessageforthepolybiusdecipherment'
- """
- grid = polybius_reverse_grid(keyword, column_order, row_order, letters_to_merge, wrap_alphabet)
- column_index_type = type(column_order[0])
- row_index_type = type(row_order[0])
- if column_first:
- pairs = [(column_index_type(p[1]), row_index_type(p[0])) for p in chunks(message, 2)]
- else:
- pairs = [(row_index_type(p[0]), column_index_type(p[1])) for p in chunks(message, 2)]
- return cat(grid[p] for p in pairs if p in grid)
-
-
-def polybius_break_mp(message, column_labels, row_labels,
- letters_to_merge=None,
- wordlist=keywords, fitness=Pletters,
- number_of_solutions=1, chunksize=500):
- """Breaks a Polybius substitution cipher using a dictionary and
- frequency analysis
-
- >>> polybius_break_mp(polybius_encipher('this is a test message for the ' \
- 'polybius decipherment', 'elephant', 'abcde', 'abcde'), \
- 'abcde', 'abcde', \
- wordlist=['cat', 'elephant', 'kangaroo']) # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
- (('elephant', <KeywordWrapAlphabet.from_a: 1>, 'abcde', 'abcde', False), \
- -54.53880...)
- >>> polybius_break_mp(polybius_encipher('this is a test message for the ' \
- 'polybius decipherment', 'elephant', 'abcde', 'abcde', column_first=True), \
- 'abcde', 'abcde', \
- wordlist=['cat', 'elephant', 'kangaroo']) # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
- (('elephant', <KeywordWrapAlphabet.from_a: 1>, 'abcde', 'abcde', True), \
- -54.53880...)
- >>> polybius_break_mp(polybius_encipher('this is a test message for the ' \
- 'polybius decipherment', 'elephant', 'abcde', 'abcde', column_first=False), \
- 'abcde', 'abcde', \
- wordlist=['cat', 'elephant', 'kangaroo']) # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
- (('elephant', <KeywordWrapAlphabet.from_a: 1>, 'abcde', 'abcde', False), \
- -54.53880...)
- >>> polybius_break_mp(polybius_encipher('this is a test message for the ' \
- 'polybius decipherment', 'elephant', 'abcde', 'pqrst', column_first=True), \
- 'abcde', 'pqrst', \
- wordlist=['cat', 'elephant', 'kangaroo']) # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
- (('elephant', <KeywordWrapAlphabet.from_a: 1>, 'abcde', 'pqrst', True), \
- -54.53880...)
- """
- if letters_to_merge is None:
- letters_to_merge = {'j': 'i'}
- with multiprocessing.Pool() as pool:
- helper_args = [(message, word, wrap,
- column_labels, row_labels, column_first,
- letters_to_merge,
- fitness)
- for word in wordlist
- for wrap in KeywordWrapAlphabet
- for column_first in [False, True]]
- # Gotcha: the helper function here needs to be defined at the top level
- # (limitation of Pool.starmap)
- breaks = pool.starmap(polybius_break_worker, helper_args, chunksize)
- if number_of_solutions == 1:
- return max(breaks, key=lambda k: k[1])
- else:
- return sorted(breaks, key=lambda k: k[1], reverse=True)[:number_of_solutions]
-
-def polybius_break_worker(message, keyword, wrap_alphabet,
- column_order, row_order, column_first,
- letters_to_merge,
- fitness):
- plaintext = polybius_decipher(message, keyword,
- column_order, row_order,
- column_first=column_first,
- letters_to_merge=letters_to_merge,
- wrap_alphabet=wrap_alphabet)
- if plaintext:
- fit = fitness(plaintext)
- else:
- fit = float('-inf')
- logger.debug('Polybius break attempt using key {0} (wrap={1}, merging {2}), '
- 'columns as {3}, rows as {4} (column_first={5}) '
- 'gives fit of {6} and decrypt starting: '
- '{7}'.format(keyword, wrap_alphabet, letters_to_merge,
- column_order, row_order, column_first,
- fit, sanitise(plaintext)[:50]))
- return (keyword, wrap_alphabet, column_order, row_order, column_first), fit
-
-if __name__ == "__main__":
- import doctest
\ No newline at end of file
projects / cipher-tools.git / blobdiff