Module szyfrow.column_transposition
+Enciphering and deciphering using the Column transposition cipher. +Also attempts to break messages that use a column transpositon cipher.
+A grid is layed out, with one column for each distinct letter in the keyword. +The grid is filled by the plaintext, one letter per cell, either in rows or +columns. The columns are rearranged so the keyword's letters are in alphabetical +order, then the ciphertext is read from the rearranged grid, either in rows +or columns.
+The Scytale cipher is a column cipher with an identity transposition, where the +message is written in rows and read in columns.
+Messages that do not fill the grid are padded with fillvalue. Note that
+pad() allows a callable, so that the message can be
+padded by random letters, for instance by calling
+random_english_letter().
+
++Expand source code +
+"""Enciphering and deciphering using the [Column transposition cipher](https://en.wikipedia.org/wiki/Bifid_cipher).
+Also attempts to break messages that use a column transpositon cipher.
+
+A grid is layed out, with one column for each distinct letter in the keyword.
+The grid is filled by the plaintext, one letter per cell, either in rows or
+columns. The columns are rearranged so the keyword's letters are in alphabetical
+order, then the ciphertext is read from the rearranged grid, either in rows
+or columns.
+
+The Scytale cipher is a column cipher with an identity transposition, where the
+message is written in rows and read in columns.
+
+Messages that do not fill the grid are padded with fillvalue. Note that
+`szyfrow.support.utilities.pad` allows a callable, so that the message can be
+padded by random letters, for instance by calling
+`szyfrow.support.language_models.random_english_letter`.
+"""
+
+import math
+import multiprocessing
+from itertools import chain
+from szyfrow.support.utilities import *
+from szyfrow.support.language_models import *
+
+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.
+
+ Note that `fillcolumnwise` and `emptycolumnwise` refer to how the message
+ is enciphered. To decipher a message, the operations are performed as an
+ inverse-empty, then inverse-transposition, then inverse-fill.
+
+ >>> 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. `rows` is the
+ circumference of the rod. The message is fitted inot columns so that
+ all rows are used.
+
+ Message is padded with spaces to allow all rows to be the same length.
+
+ For ease of implementation, the cipher is performed on the transpose
+ of the grid
+
+ >>> 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(message, translist=None,
+ fitness=Pbigrams, chunksize=500):
+ """Breaks a column transposition cipher using a dictionary and
+ n-gram frequency analysis
+
+ If `translist` is not specified, use
+ [`szyfrow.support.langauge_models.transpositions`](support/language_models.html#szyfrow.support.language_models.transpositions).
+
+ >>> len(keywords)
+ 20
+
+ >>> column_transposition_break(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(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...)
+ """
+ if translist is None:
+ translist = transpositions
+
+ 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])
+
+def column_transposition_break_worker(message, transposition,
+ fillcolumnwise, emptycolumnwise, fitness):
+ plaintext = column_transposition_decipher(message, transposition,
+ fillcolumnwise=fillcolumnwise, emptycolumnwise=emptycolumnwise)
+ fit = fitness(sanitise(plaintext))
+ return (transposition, fillcolumnwise, emptycolumnwise), fit
+
+
+def scytale_break(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(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(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 multiprocessing.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]
+
+if __name__ == "__main__":
+ import doctestFunctions
+-
+
+def cat(iterable, /) +
+-
++
Concatenate any number of strings.
+The string whose method is called is inserted in between each given string. +The result is returned as a new string.
+Example: '.'.join(['ab', 'pq', 'rs']) -> 'ab.pq.rs'
+ +def column_transposition_break(message, translist=None, fitness=<function Pbigrams>, chunksize=500) +
+-
++
Breaks a column transposition cipher using a dictionary and +n-gram frequency analysis
+If
+translistis not specified, use +szyfrow.support.langauge_models.transpositions.
+>>> len(keywords) +20 +>>> column_transposition_break(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(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...) ++++Expand source code +
+
+def column_transposition_break(message, translist=None, + fitness=Pbigrams, chunksize=500): + """Breaks a column transposition cipher using a dictionary and + n-gram frequency analysis + + If `translist` is not specified, use + [`szyfrow.support.langauge_models.transpositions`](support/language_models.html#szyfrow.support.language_models.transpositions). + + >>> len(keywords) + 20 + + >>> column_transposition_break(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(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...) + """ + if translist is None: + translist = transpositions + + 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])
+ +def column_transposition_break_worker(message, transposition, fillcolumnwise, emptycolumnwise, fitness) +
+-
+
+++
+Expand source code +
+
+def column_transposition_break_worker(message, transposition, + fillcolumnwise, emptycolumnwise, fitness): + plaintext = column_transposition_decipher(message, transposition, + fillcolumnwise=fillcolumnwise, emptycolumnwise=emptycolumnwise) + fit = fitness(sanitise(plaintext)) + return (transposition, fillcolumnwise, emptycolumnwise), fit
+ +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.
+Note that
+fillcolumnwiseandemptycolumnwiserefer to how the message +is enciphered. To decipher a message, the operations are performed as an +inverse-empty, then inverse-transposition, then inverse-fill.>>> 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' ++++Expand source code +
+
+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. + + Note that `fillcolumnwise` and `emptycolumnwise` refer to how the message + is enciphered. To decipher a message, the operations are performed as an + inverse-empty, then inverse-transposition, then inverse-fill. + + >>> 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 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*' ++++Expand source code +
+
+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 lcat(iterable, /) +
+-
++
Concatenate any number of strings.
+The string whose method is called is inserted in between each given string. +The result is returned as a new string.
+Example: '.'.join(['ab', 'pq', 'rs']) -> 'ab.pq.rs'
+ +def scytale_break(message, max_key_length=20, fitness=<function Pbigrams>, chunksize=500) +
+-
++
Breaks a scytale cipher using a range of lengths and +n-gram frequency analysis
+>>> scytale_break(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(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...) ++++Expand source code +
+
+def scytale_break(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(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(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 multiprocessing.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]
+ +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 ' ++++Expand source code +
+
+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 scytale_encipher(message, rows, fillvalue=' ') +
+-
++
Enciphers using the scytale transposition cipher.
+rowsis the +circumference of the rod. The message is fitted inot columns so that +all rows are used.Message is padded with spaces to allow all rows to be the same length.
+For ease of implementation, the cipher is performed on the transpose +of the grid
+>>> 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 ' ++++Expand source code +
+
+def scytale_encipher(message, rows, fillvalue=' '): + """Enciphers using the scytale transposition cipher. `rows` is the + circumference of the rod. The message is fitted inot columns so that + all rows are used. + + Message is padded with spaces to allow all rows to be the same length. + + For ease of implementation, the cipher is performed on the transpose + of the grid + + >>> 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 wcat(iterable, /) +
+-
++
Concatenate any number of strings.
+The string whose method is called is inserted in between each given string. +The result is returned as a new string.
+Example: '.'.join(['ab', 'pq', 'rs']) -> 'ab.pq.rs'
+