+++ /dev/null
-from utilities import *
-from language_models import *
-import multiprocessing
-from itertools import chain
-
-from logger import logger
-
-def transpositions_of(keyword):
- """Finds the transpostions given by a keyword. For instance, the keyword
- 'clever' rearranges to 'celrv', so the first column (0) stays first, the
- second column (1) moves to third, the third column (2) moves to second,
- and so on.
-
- If passed a tuple, assume it's already a transposition and just return it.
-
- >>> transpositions_of('clever')
- (0, 2, 1, 4, 3)
- >>> transpositions_of('fred')
- (3, 2, 0, 1)
- >>> transpositions_of((3, 2, 0, 1))
- (3, 2, 0, 1)
- """
- if isinstance(keyword, tuple):
- return keyword
- else:
- key = deduplicate(keyword)
- transpositions = tuple(key.index(l) for l in sorted(key))
- return transpositions
-
-
-transpositions = collections.defaultdict(list)
-for word in keywords:
- transpositions[transpositions_of(word)] += [word]
-
-
-def pad(message_len, group_len, fillvalue):
- padding_length = group_len - message_len % group_len
- if padding_length == group_len: padding_length = 0
- padding = ''
- for i in range(padding_length):
- if callable(fillvalue):
- padding += fillvalue()
- else:
- padding += fillvalue
- return padding
-
-def column_transposition_encipher(message, keyword, fillvalue=' ',
- fillcolumnwise=False,
- emptycolumnwise=False):
- """Enciphers using the column transposition cipher.
- Message is padded to allow all rows to be the same length.
-
- >>> column_transposition_encipher('hellothere', 'abcdef', fillcolumnwise=True)
- 'hlohr eltee '
- >>> column_transposition_encipher('hellothere', 'abcdef', fillcolumnwise=True, emptycolumnwise=True)
- 'hellothere '
- >>> column_transposition_encipher('hellothere', 'abcdef')
- 'hellothere '
- >>> column_transposition_encipher('hellothere', 'abcde')
- 'hellothere'
- >>> column_transposition_encipher('hellothere', 'abcde', fillcolumnwise=True, emptycolumnwise=True)
- 'hellothere'
- >>> column_transposition_encipher('hellothere', 'abcde', fillcolumnwise=True, emptycolumnwise=False)
- 'hlohreltee'
- >>> column_transposition_encipher('hellothere', 'abcde', fillcolumnwise=False, emptycolumnwise=True)
- 'htehlelroe'
- >>> column_transposition_encipher('hellothere', 'abcde', fillcolumnwise=False, emptycolumnwise=False)
- 'hellothere'
- >>> column_transposition_encipher('hellothere', 'clever', fillcolumnwise=True, emptycolumnwise=True)
- 'heotllrehe'
- >>> column_transposition_encipher('hellothere', 'clever', fillcolumnwise=True, emptycolumnwise=False)
- 'holrhetlee'
- >>> column_transposition_encipher('hellothere', 'clever', fillcolumnwise=False, emptycolumnwise=True)
- 'htleehoelr'
- >>> column_transposition_encipher('hellothere', 'clever', fillcolumnwise=False, emptycolumnwise=False)
- 'hleolteher'
- >>> column_transposition_encipher('hellothere', 'cleverly')
- 'hleolthre e '
- >>> column_transposition_encipher('hellothere', 'cleverly', fillvalue='!')
- 'hleolthre!e!'
- >>> column_transposition_encipher('hellothere', 'cleverly', fillvalue=lambda: '*')
- 'hleolthre*e*'
- """
- transpositions = transpositions_of(keyword)
- message += pad(len(message), len(transpositions), fillvalue)
- if fillcolumnwise:
- rows = every_nth(message, len(message) // len(transpositions))
- else:
- rows = chunks(message, len(transpositions))
- transposed = [transpose(r, transpositions) for r in rows]
- if emptycolumnwise:
- return combine_every_nth(transposed)
- else:
- return cat(chain(*transposed))
-
-def column_transposition_decipher(message, keyword, fillvalue=' ',
- fillcolumnwise=False,
- emptycolumnwise=False):
- """Deciphers using the column transposition cipher.
- Message is padded to allow all rows to be the same length.
-
- >>> column_transposition_decipher('hellothere', 'abcde', fillcolumnwise=True, emptycolumnwise=True)
- 'hellothere'
- >>> column_transposition_decipher('hlohreltee', 'abcde', fillcolumnwise=True, emptycolumnwise=False)
- 'hellothere'
- >>> column_transposition_decipher('htehlelroe', 'abcde', fillcolumnwise=False, emptycolumnwise=True)
- 'hellothere'
- >>> column_transposition_decipher('hellothere', 'abcde', fillcolumnwise=False, emptycolumnwise=False)
- 'hellothere'
- >>> column_transposition_decipher('heotllrehe', 'clever', fillcolumnwise=True, emptycolumnwise=True)
- 'hellothere'
- >>> column_transposition_decipher('holrhetlee', 'clever', fillcolumnwise=True, emptycolumnwise=False)
- 'hellothere'
- >>> column_transposition_decipher('htleehoelr', 'clever', fillcolumnwise=False, emptycolumnwise=True)
- 'hellothere'
- >>> column_transposition_decipher('hleolteher', 'clever', fillcolumnwise=False, emptycolumnwise=False)
- 'hellothere'
- """
- transpositions = transpositions_of(keyword)
- message += pad(len(message), len(transpositions), fillvalue)
- if emptycolumnwise:
- rows = every_nth(message, len(message) // len(transpositions))
- else:
- rows = chunks(message, len(transpositions))
- untransposed = [untranspose(r, transpositions) for r in rows]
- if fillcolumnwise:
- return combine_every_nth(untransposed)
- else:
- return cat(chain(*untransposed))
-
-def scytale_encipher(message, rows, fillvalue=' '):
- """Enciphers using the scytale transposition cipher.
- Message is padded with spaces to allow all rows to be the same length.
-
- >>> scytale_encipher('thequickbrownfox', 3)
- 'tcnhkfeboqrxuo iw '
- >>> scytale_encipher('thequickbrownfox', 4)
- 'tubnhirfecooqkwx'
- >>> scytale_encipher('thequickbrownfox', 5)
- 'tubn hirf ecoo qkwx '
- >>> scytale_encipher('thequickbrownfox', 6)
- 'tqcrnxhukof eibwo '
- >>> scytale_encipher('thequickbrownfox', 7)
- 'tqcrnx hukof eibwo '
- """
- # transpositions = [i for i in range(math.ceil(len(message) / rows))]
- # return column_transposition_encipher(message, transpositions,
- # fillvalue=fillvalue, fillcolumnwise=False, emptycolumnwise=True)
- transpositions = [i for i in range(rows)]
- return column_transposition_encipher(message, transpositions,
- fillvalue=fillvalue, fillcolumnwise=True, emptycolumnwise=False)
-
-def scytale_decipher(message, rows):
- """Deciphers using the scytale transposition cipher.
- Assumes the message is padded so that all rows are the same length.
-
- >>> scytale_decipher('tcnhkfeboqrxuo iw ', 3)
- 'thequickbrownfox '
- >>> scytale_decipher('tubnhirfecooqkwx', 4)
- 'thequickbrownfox'
- >>> scytale_decipher('tubn hirf ecoo qkwx ', 5)
- 'thequickbrownfox '
- >>> scytale_decipher('tqcrnxhukof eibwo ', 6)
- 'thequickbrownfox '
- >>> scytale_decipher('tqcrnx hukof eibwo ', 7)
- 'thequickbrownfox '
- """
- # transpositions = [i for i in range(math.ceil(len(message) / rows))]
- # return column_transposition_decipher(message, transpositions,
- # fillcolumnwise=False, emptycolumnwise=True)
- transpositions = [i for i in range(rows)]
- return column_transposition_decipher(message, transpositions,
- fillcolumnwise=True, emptycolumnwise=False)
-
-
-def column_transposition_break_mp(message, translist=transpositions,
- fitness=Pbigrams, chunksize=500):
- """Breaks a column transposition cipher using a dictionary and
- n-gram frequency analysis
-
- >>> column_transposition_break_mp(column_transposition_encipher(sanitise( \
- "It is a truth universally acknowledged, that a single man in \
- possession of a good fortune, must be in want of a wife. However \
- little known the feelings or views of such a man may be on his \
- first entering a neighbourhood, this truth is so well fixed in \
- the minds of the surrounding families, that he is considered the \
- rightful property of some one or other of their daughters."), \
- 'encipher'), \
- translist={(2, 0, 5, 3, 1, 4, 6): ['encipher'], \
- (5, 0, 6, 1, 3, 4, 2): ['fourteen'], \
- (6, 1, 0, 4, 5, 3, 2): ['keyword']}) # doctest: +ELLIPSIS
- (((2, 0, 5, 3, 1, 4, 6), False, False), -709.4646722...)
- >>> column_transposition_break_mp(column_transposition_encipher(sanitise( \
- "It is a truth universally acknowledged, that a single man in \
- possession of a good fortune, must be in want of a wife. However \
- little known the feelings or views of such a man may be on his \
- first entering a neighbourhood, this truth is so well fixed in \
- the minds of the surrounding families, that he is considered the \
- rightful property of some one or other of their daughters."), \
- 'encipher'), \
- translist={(2, 0, 5, 3, 1, 4, 6): ['encipher'], \
- (5, 0, 6, 1, 3, 4, 2): ['fourteen'], \
- (6, 1, 0, 4, 5, 3, 2): ['keyword']}, \
- fitness=Ptrigrams) # doctest: +ELLIPSIS
- (((2, 0, 5, 3, 1, 4, 6), False, False), -997.0129085...)
- """
- with multiprocessing.Pool() as pool:
- helper_args = [(message, trans, fillcolumnwise, emptycolumnwise,
- fitness)
- for trans in translist
- for fillcolumnwise in [True, False]
- for emptycolumnwise in [True, False]]
- # Gotcha: the helper function here needs to be defined at the top level
- # (limitation of Pool.starmap)
- breaks = pool.starmap(column_transposition_break_worker,
- helper_args, chunksize)
- return max(breaks, key=lambda k: k[1])
-column_transposition_break = column_transposition_break_mp
-
-def column_transposition_break_worker(message, transposition,
- fillcolumnwise, emptycolumnwise, fitness):
- plaintext = column_transposition_decipher(message, transposition,
- fillcolumnwise=fillcolumnwise, emptycolumnwise=emptycolumnwise)
- fit = fitness(sanitise(plaintext))
- logger.debug('Column transposition break attempt using key {0} '
- 'gives fit of {1} and decrypt starting: {2}'.format(
- transposition, fit,
- sanitise(plaintext)[:50]))
- return (transposition, fillcolumnwise, emptycolumnwise), fit
-
-
-def scytale_break_mp(message, max_key_length=20,
- fitness=Pbigrams, chunksize=500):
- """Breaks a scytale cipher using a range of lengths and
- n-gram frequency analysis
-
- >>> scytale_break_mp(scytale_encipher(sanitise( \
- "It is a truth universally acknowledged, that a single man in \
- possession of a good fortune, must be in want of a wife. However \
- little known the feelings or views of such a man may be on his \
- first entering a neighbourhood, this truth is so well fixed in \
- the minds of the surrounding families, that he is considered the \
- rightful property of some one or other of their daughters."), \
- 5)) # doctest: +ELLIPSIS
- (5, -709.4646722...)
- >>> scytale_break_mp(scytale_encipher(sanitise( \
- "It is a truth universally acknowledged, that a single man in \
- possession of a good fortune, must be in want of a wife. However \
- little known the feelings or views of such a man may be on his \
- first entering a neighbourhood, this truth is so well fixed in \
- the minds of the surrounding families, that he is considered the \
- rightful property of some one or other of their daughters."), \
- 5), \
- fitness=Ptrigrams) # doctest: +ELLIPSIS
- (5, -997.0129085...)
- """
- with Pool() as pool:
- helper_args = [(message, trans, False, True, fitness)
- for trans in
- [[col for col in range(math.ceil(len(message)/rows))]
- for rows in range(1,max_key_length+1)]]
- # Gotcha: the helper function here needs to be defined at the top level
- # (limitation of Pool.starmap)
- breaks = pool.starmap(column_transposition_break_worker,
- helper_args, chunksize)
- best = max(breaks, key=lambda k: k[1])
- return math.trunc(len(message) / len(best[0][0])), best[1]
-scytale_break = scytale_break_mp
-
-if __name__ == "__main__":
- import doctest
\ No newline at end of file
projects / cipher-tools.git / blobdiff