+"""A set of functions to break the ciphers give in ciphers.py.
+"""
+
import string
import collections
import norms
import logging
-from itertools import zip_longest, cycle, permutations
+import random
+import math
+from itertools import starmap
from segment import segment
from multiprocessing import Pool
-from math import log10
import matplotlib.pyplot as plt
# timeit.timeit('keyword_break(c5a)', setup='gc.enable() ; from __main__ import c5a ; from cipher import keyword_break', number=1)
# timeit.repeat('keyword_break_mp(c5a, chunksize=500)', setup='gc.enable() ; from __main__ import c5a ; from cipher import keyword_break_mp', repeat=5, number=1)
-transpositions = collections.defaultdict(list)
-for word in keywords:
- transpositions[transpositions_of(word)] += [word]
def frequencies(text):
"""Count the number of occurrences of each character in text
-
+
>>> sorted(frequencies('abcdefabc').items())
[('a', 2), ('b', 2), ('c', 2), ('d', 1), ('e', 1), ('f', 1)]
>>> sorted(frequencies('the quick brown fox jumped over the lazy ' \
'dog').items()) # doctest: +NORMALIZE_WHITESPACE
- [(' ', 8), ('a', 1), ('b', 1), ('c', 1), ('d', 2), ('e', 4), ('f', 1),
- ('g', 1), ('h', 2), ('i', 1), ('j', 1), ('k', 1), ('l', 1), ('m', 1),
- ('n', 1), ('o', 4), ('p', 1), ('q', 1), ('r', 2), ('t', 2), ('u', 2),
+ [(' ', 8), ('a', 1), ('b', 1), ('c', 1), ('d', 2), ('e', 4), ('f', 1),
+ ('g', 1), ('h', 2), ('i', 1), ('j', 1), ('k', 1), ('l', 1), ('m', 1),
+ ('n', 1), ('o', 4), ('p', 1), ('q', 1), ('r', 2), ('t', 2), ('u', 2),
('v', 1), ('w', 1), ('x', 1), ('y', 1), ('z', 1)]
>>> sorted(frequencies('The Quick BROWN fox jumped! over... the ' \
'(9lazy) DOG').items()) # doctest: +NORMALIZE_WHITESPACE
- [(' ', 8), ('!', 1), ('(', 1), (')', 1), ('.', 3), ('9', 1), ('B', 1),
- ('D', 1), ('G', 1), ('N', 1), ('O', 2), ('Q', 1), ('R', 1), ('T', 1),
- ('W', 1), ('a', 1), ('c', 1), ('d', 1), ('e', 4), ('f', 1), ('h', 2),
- ('i', 1), ('j', 1), ('k', 1), ('l', 1), ('m', 1), ('o', 2), ('p', 1),
+ [(' ', 8), ('!', 1), ('(', 1), (')', 1), ('.', 3), ('9', 1), ('B', 1),
+ ('D', 1), ('G', 1), ('N', 1), ('O', 2), ('Q', 1), ('R', 1), ('T', 1),
+ ('W', 1), ('a', 1), ('c', 1), ('d', 1), ('e', 4), ('f', 1), ('h', 2),
+ ('i', 1), ('j', 1), ('k', 1), ('l', 1), ('m', 1), ('o', 2), ('p', 1),
('r', 1), ('t', 1), ('u', 2), ('v', 1), ('x', 1), ('y', 1), ('z', 1)]
- >>> sorted(frequencies(sanitise('The Quick BROWN fox jumped! over... ' \
+ >>> sorted(frequencies(sanitise('The Quick BROWN fox jumped! over... '\
'the (9lazy) DOG')).items()) # doctest: +NORMALIZE_WHITESPACE
- [('a', 1), ('b', 1), ('c', 1), ('d', 2), ('e', 4), ('f', 1), ('g', 1),
- ('h', 2), ('i', 1), ('j', 1), ('k', 1), ('l', 1), ('m', 1), ('n', 1),
- ('o', 4), ('p', 1), ('q', 1), ('r', 2), ('t', 2), ('u', 2), ('v', 1),
+ [('a', 1), ('b', 1), ('c', 1), ('d', 2), ('e', 4), ('f', 1), ('g', 1),
+ ('h', 2), ('i', 1), ('j', 1), ('k', 1), ('l', 1), ('m', 1), ('n', 1),
+ ('o', 4), ('p', 1), ('q', 1), ('r', 2), ('t', 2), ('u', 2), ('v', 1),
('w', 1), ('x', 1), ('y', 1), ('z', 1)]
>>> frequencies('abcdefabcdef')['x']
0
def caesar_break(message, fitness=Pletters):
"""Breaks a Caesar cipher using frequency analysis
-
+
>>> caesar_break('ibxcsyorsaqcheyklxivoexlevmrimwxsfiqevvmihrsasrxliwyrh' \
'ecjsppsamrkwleppfmergefifvmhixscsymjcsyqeoixlm') # doctest: +ELLIPSIS
(4, -130.849989015...)
plaintext = caesar_decipher(sanitised_message, shift)
fit = fitness(plaintext)
logger.debug('Caesar break attempt using key {0} gives fit of {1} '
- 'and decrypt starting: {2}'.format(shift, fit, plaintext[:50]))
+ 'and decrypt starting: {2}'.format(shift, fit,
+ plaintext[:50]))
if fit > best_fit:
best_fit = fit
best_shift = shift
def affine_break(message, fitness=Pletters):
"""Breaks an affine cipher using frequency analysis
-
+
>>> affine_break('lmyfu bkuusd dyfaxw claol psfaom jfasd snsfg jfaoe ls ' \
'omytd jlaxe mh jm bfmibj umis hfsul axubafkjamx. ls kffkxwsd jls ' \
'ofgbjmwfkiu olfmxmtmwaokttg jlsx ls kffkxwsd jlsi zg tsxwjl. jlsx ' \
for one_based in [True, False]:
for multiplier in [x for x in range(1, 26, 2) if x != 13]:
for adder in range(26):
- plaintext = affine_decipher(sanitised_message,
+ plaintext = affine_decipher(sanitised_message,
multiplier, adder, one_based)
fit = fitness(plaintext)
logger.debug('Affine break attempt using key {0}x+{1} ({2}) '
'gives fit of {3} and decrypt starting: {4}'.
- format(multiplier, adder, one_based, fit,
+ format(multiplier, adder, one_based, fit,
plaintext[:50]))
if fit > best_fit:
best_fit = fit
best_multiplier = multiplier
best_adder = adder
best_one_based = one_based
- logger.info('Affine break best fit with key {0}x+{1} ({2}) gives fit of {3} '
- 'and decrypt starting: {4}'.format(
- best_multiplier, best_adder, best_one_based, best_fit,
- affine_decipher(sanitised_message, best_multiplier,
- best_adder, best_one_based)[:50]))
+ logger.info('Affine break best fit with key {0}x+{1} ({2}) gives fit of '
+ '{3} and decrypt starting: {4}'.format(
+ best_multiplier, best_adder, best_one_based, best_fit,
+ affine_decipher(sanitised_message, best_multiplier,
+ best_adder, best_one_based)[:50]))
return (best_multiplier, best_adder, best_one_based), best_fit
-def keyword_break(message, wordlist=keywords, fitness=Pletters):
- """Breaks a keyword substitution cipher using a dictionary and
- frequency analysis
-
- >>> keyword_break(keyword_encipher('this is a test message for the ' \
- 'keyword decipherment', 'elephant', Keyword_wrap_alphabet.from_last), \
- wordlist=['cat', 'elephant', 'kangaroo']) # doctest: +ELLIPSIS
- (('elephant', <Keyword_wrap_alphabet.from_last: 2>), -52.834575011...)
- """
- best_keyword = ''
- best_wrap_alphabet = True
- best_fit = float("-inf")
- for wrap_alphabet in Keyword_wrap_alphabet:
- for keyword in wordlist:
- plaintext = keyword_decipher(message, keyword, wrap_alphabet)
- fit = fitness(plaintext)
- logger.debug('Keyword break attempt using key {0} (wrap={1}) '
- 'gives fit of {2} and decrypt starting: {3}'.format(
- keyword, wrap_alphabet, fit,
- sanitise(plaintext)[:50]))
- if fit > best_fit:
- best_fit = fit
- best_keyword = keyword
- best_wrap_alphabet = wrap_alphabet
- logger.info('Keyword break best fit with key {0} (wrap={1}) gives fit of '
- '{2} and decrypt starting: {3}'.format(best_keyword,
- best_wrap_alphabet, best_fit, sanitise(
- keyword_decipher(message, best_keyword,
- best_wrap_alphabet))[:50]))
- return (best_keyword, best_wrap_alphabet), best_fit
-
-def keyword_break_mp(message, wordlist=keywords, fitness=Pletters, chunksize=500):
- """Breaks a keyword substitution cipher using a dictionary and
- frequency analysis
-
- >>> keyword_break_mp(keyword_encipher('this is a test message for the ' \
- 'keyword decipherment', 'elephant', Keyword_wrap_alphabet.from_last), \
- wordlist=['cat', 'elephant', 'kangaroo']) # doctest: +ELLIPSIS
- (('elephant', <Keyword_wrap_alphabet.from_last: 2>), -52.834575011...)
- """
- with Pool() as pool:
- helper_args = [(message, word, wrap, fitness)
- for word in wordlist
- for wrap in Keyword_wrap_alphabet]
- # Gotcha: the helper function here needs to be defined at the top level
- # (limitation of Pool.starmap)
- breaks = pool.starmap(keyword_break_worker, helper_args, chunksize)
- return max(breaks, key=lambda k: k[1])
-
-def keyword_break_worker(message, keyword, wrap_alphabet, fitness):
- plaintext = keyword_decipher(message, keyword, wrap_alphabet)
- fit = fitness(plaintext)
- logger.debug('Keyword break attempt using key {0} (wrap={1}) gives fit of '
- '{2} and decrypt starting: {3}'.format(keyword,
- 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...)
- """
- with Pool() as pool:
- helper_args = [(message, trans, fillcolumnwise, emptycolumnwise,
- fitness)
- for trans in translist.keys()
- 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 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...)
- """
- 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
-
-def vigenere_keyword_break_mp(message, wordlist=keywords, fitness=Pletters,
- chunksize=500):
- """Breaks a vigenere cipher using a dictionary and
- frequency analysis
-
- >>> vigenere_keyword_break_mp(vigenere_encipher(sanitise('this is a test ' \
- 'message for the vigenere decipherment'), 'cat'), \
- wordlist=['cat', 'elephant', 'kangaroo']) # doctest: +ELLIPSIS
- ('cat', -52.947271216...)
- """
- with Pool() as pool:
- helper_args = [(message, word, fitness)
- for word in wordlist]
- # Gotcha: the helper function here needs to be defined at the top level
- # (limitation of Pool.starmap)
- breaks = pool.starmap(vigenere_keyword_break_worker, helper_args, chunksize)
- return max(breaks, key=lambda k: k[1])
-
-def vigenere_keyword_break_worker(message, keyword, fitness):
- plaintext = vigenere_decipher(message, keyword)
- fit = fitness(plaintext)
- logger.debug('Vigenere keyword break attempt using key {0} gives fit of '
- '{1} and decrypt starting: {2}'.format(keyword,
- fit, sanitise(plaintext)[:50]))
- return keyword, fit
-
-
-
-def vigenere_frequency_break(message, fitness=Pletters):
- """Breaks a Vigenere cipher with frequency analysis
-
- >>> vigenere_frequency_break(vigenere_encipher(sanitise("It is time to " \
- "run. She is ready and so am I. I stole Daniel's pocketbook this " \
- "afternoon when he left his jacket hanging on the easel in the " \
- "attic. I jump every time I hear a footstep on the stairs, " \
- "certain that the theft has been discovered and that I will " \
- "be caught. The SS officer visits less often now 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)
- key = ''.join([chr(caesar_break(s)[0] + ord('a')) for s in splits])
- plaintext = vigenere_decipher(sanitised_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):
- """Breaks a Beaufort cipher with frequency analysis
-
- >>> beaufort_frequency_break(beaufort_encipher(sanitise("It is time to " \
- "run. She is ready and so am I. I stole Daniel's pocketbook this " \
- "afternoon when he left his jacket hanging on the easel in the " \
- "attic. I jump every time I hear a footstep on the stairs, " \
- "certain that the theft has been discovered and that I will " \
- "be caught. The SS officer visits less often now " \
- "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)
- key = ''.join([chr(-caesar_break(s)[0] % 26 + ord('a')) for s in splits])
- plaintext = beaufort_decipher(sanitised_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
-
-
def plot_frequency_histogram(freqs, sort_key=None):
x = range(len(freqs.keys()))
if __name__ == "__main__":
import doctest
doctest.testmod()
-
projects / cipher-training.git / blobdiff