import collections
import norms
import logging
-from itertools import zip_longest, cycle, permutations
+from itertools import zip_longest, cycle, permutations, starmap
from segment import segment
from multiprocessing import Pool
from math import log10
wrap_alphabet, fit, sanitise(plaintext)[:50]))
return (keyword, wrap_alphabet), fit
-def scytale_break(message, fitness=Pbigrams):
- """Breaks a Scytale cipher
-
- >>> scytale_break('tfeulchtrtteehwahsdehneoifeayfsondmwpltmaoalhikotoere' \
- 'dcweatehiplwxsnhooacgorrcrcraotohsgullasenylrendaianeplscdriioto' \
- 'aek') # doctest: +ELLIPSIS
- (6, -281.276219108...)
- """
- best_key = 0
- best_fit = float("-inf")
- for key in range(1, 20):
- if len(message) % key == 0:
- plaintext = scytale_decipher(message, key)
- fit = fitness(sanitise(plaintext))
- logger.debug('Scytale break attempt using key {0} gives fit of '
- '{1} and decrypt starting: {2}'.format(key,
- fit, sanitise(plaintext)[:50]))
- if fit > best_fit:
- best_fit = fit
- best_key = key
- logger.info('Scytale break best fit with key {0} gives fit of {1} and '
- 'decrypt starting: {2}'.format(best_key, best_fit,
- sanitise(scytale_decipher(message, best_key))[:50]))
- return best_key, best_fit
-
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...)
"""
- # >>> 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), 0.0628106372...)
- # >>> 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']}, \
- # target_counts=normalised_english_trigram_counts) # doctest: +ELLIPSIS
- # (((2, 0, 5, 3, 1, 4, 6), False), 0.0592259560...)
- # """
with Pool() as pool:
- helper_args = [(message, trans, columnwise, fitness)
+ helper_args = [(message, trans, fillcolumnwise, emptycolumnwise,
+ fitness)
for trans in translist.keys()
- for columnwise in [True, False]]
+ 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,
return max(breaks, key=lambda k: k[1])
column_transposition_break = column_transposition_break_mp
-def column_transposition_break_worker(message, transposition, columnwise,
- fitness):
- plaintext = column_transposition_decipher(message, transposition, columnwise=columnwise)
+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, columnwise), fit
-
-
-def transposition_break_exhaustive(message, fitness=Pbigrams):
- best_transposition = ''
- best_pw = float('-inf')
- for keylength in range(1, 21):
- if len(message) % keylength == 0:
- for transposition in permutations(range(keylength)):
- for columnwise in [True, False]:
- plaintext = column_transposition_decipher(message,
- transposition, columnwise=columnwise)
- fit=fitness(plaintext)
- logger.debug('Column transposition break attempt using key {0} {1} '
- 'gives fit of {2} and decrypt starting: {3}'.format(
- transposition, columnwise, pw,
- sanitise(plaintext)[:50]))
- if fit > best_fit:
- best_transposition = transposition
- best_columnwise = columnwise
- best_fit = fit
- return (best_transposition, best_columnwise), best_pw
+ return (transposition, fillcolumnwise, emptycolumnwise), fit
-def vigenere_keyword_break(message, wordlist=keywords, fitness=Pletters):
- """Breaks a vigenere cipher using a dictionary and
- frequency analysis
-
- >>> vigenere_keyword_break(vigenere_encipher(sanitise('this is a test ' \
- 'message for the vigenere decipherment'), 'cat'), \
- wordlist=['cat', 'elephant', 'kangaroo']) # doctest: +ELLIPSIS
- ('cat', -52.947271216...)
+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...)
"""
- best_keyword = ''
- best_fit = float("-inf")
- for keyword in wordlist:
- plaintext = vigenere_decipher(message, keyword)
- fit = fitness(plaintext)
- logger.debug('Vigenere break attempt using key {0} '
- 'gives fit of {1} and decrypt starting: {2}'.format(
- keyword, fit,
- sanitise(plaintext)[:50]))
- if fit > best_fit:
- best_fit = fit
- best_keyword = keyword
- logger.info('Vigenere break best fit with key {0} gives fit '
- 'of {1} and decrypt starting: {2}'.format(best_keyword,
- best_fit, sanitise(
- vigenere_decipher(message, best_keyword))[:50]))
- return best_keyword, best_fit
+ 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
+
def vigenere_keyword_break_mp(message, wordlist=keywords, fitness=Pletters,
chunksize=500):
# (limitation of Pool.starmap)
breaks = pool.starmap(vigenere_keyword_break_worker, helper_args, chunksize)
return max(breaks, key=lambda k: k[1])
+vigenere_keyword_break = vigenere_keyword_break_mp
def vigenere_keyword_break_worker(message, keyword, fitness):
plaintext = vigenere_decipher(message, keyword)
-def vigenere_frequency_break(message, fitness=Pletters):
+def vigenere_frequency_break(message, max_key_length=20, fitness=Pletters):
"""Breaks a Vigenere cipher with frequency analysis
>>> vigenere_frequency_break(vigenere_encipher(sanitise("It is time to " \
"sure"), 'florence')) # doctest: +ELLIPSIS
('florence', -307.5473096791...)
"""
- best_fit = float("-inf")
- best_key = ''
- sanitised_message = sanitise(message)
- for trial_length in range(1, 20):
- splits = every_nth(sanitised_message, trial_length)
+ def worker(message, key_length, fitness):
+ splits = every_nth(sanitised_message, key_length)
key = ''.join([chr(caesar_break(s)[0] + ord('a')) for s in splits])
- plaintext = vigenere_decipher(sanitised_message, key)
+ plaintext = vigenere_decipher(message, key)
fit = fitness(plaintext)
- logger.debug('Vigenere key length of {0} ({1}) gives fit of {2}'.
- format(trial_length, key, fit))
- if fit > best_fit:
- best_fit = fit
- best_key = key
- logger.info('Vigenere break best fit with key {0} gives fit '
- 'of {1} and decrypt starting: {2}'.format(best_key,
- best_fit, sanitise(
- vigenere_decipher(message, best_key))[:50]))
- return best_key, best_fit
-
-def beaufort_frequency_break(message, fitness=Pletters):
+ return key, fit
+ sanitised_message = sanitise(message)
+ results = starmap(worker, [(sanitised_message, i, fitness)
+ for i in range(1, max_key_length+1)])
+ return max(results, key=lambda k: k[1])
+
+
+def beaufort_frequency_break(message, max_key_length=20, fitness=Pletters):
"""Breaks a Beaufort cipher with frequency analysis
>>> beaufort_frequency_break(beaufort_encipher(sanitise("It is time to " \
"that he is sure"), 'florence')) # doctest: +ELLIPSIS
('florence', -307.5473096791...)
"""
- best_fit = float("-inf")
- best_key = ''
- sanitised_message = sanitise(message)
- for trial_length in range(1, 20):
- splits = every_nth(sanitised_message, trial_length)
+ def worker(message, key_length, fitness):
+ splits = every_nth(sanitised_message, key_length)
key = ''.join([chr(-caesar_break(s)[0] % 26 + ord('a')) for s in splits])
- plaintext = beaufort_decipher(sanitised_message, key)
+ plaintext = beaufort_decipher(message, key)
fit = fitness(plaintext)
- logger.debug('Beaufort key length of {0} ({1}) gives fit of {2}'.
- format(trial_length, key, fit))
- if fit > best_fit:
- best_fit = fit
- best_key = key
- logger.info('Beaufort break best fit with key {0} gives fit '
- 'of {1} and decrypt starting: {2}'.format(best_key,
- best_fit, sanitise(
- beaufort_decipher(message, best_key))[:50]))
- return best_key, best_fit
-
+ return key, fit
+ sanitised_message = sanitise(message)
+ results = starmap(worker, [(sanitised_message, i, fitness)
+ for i in range(1, max_key_length+1)])
+ return max(results, key=lambda k: k[1])
def plot_frequency_histogram(freqs, sort_key=None):
projects / cipher-training.git / commitdiff
