+"""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
+
from cipher import *
from language_models import *
# 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),
- ('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),
- ('r', 1), ('t', 1), ('u', 2), ('v', 1), ('x', 1), ('y', 1), ('z', 1)]
- >>> 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),
- ('w', 1), ('x', 1), ('y', 1), ('z', 1)]
- >>> frequencies('abcdefabcdef')['x']
- 0
- """
- #counts = collections.defaultdict(int)
- #for c in text:
- # counts[c] += 1
- #return counts
- return collections.Counter(c for c in text)
-def caesar_break(message, fitness=Pletters):
- """Breaks a Caesar cipher using frequency analysis
-
- >>> caesar_break('ibxcsyorsaqcheyklxivoexlevmrimwxsfiqevvmihrsasrxliwyrh' \
- 'ecjsppsamrkwleppfmergefifvmhixscsymjcsyqeoixlm') # doctest: +ELLIPSIS
- (4, -130.849890899...)
- >>> caesar_break('wxwmaxdgheetgwuxztgptedbgznitgwwhpguxyhkxbmhvvtlbhgtee' \
- 'raxlmhiixweblmxgxwmhmaxybkbgztgwztsxwbgmxgmert') # doctest: +ELLIPSIS
- (19, -128.82516920...)
- >>> caesar_break('yltbbqnqnzvguvaxurorgenafsbezqvagbnornfgsbevpnaabjurer' \
- 'svaquvzyvxrnznazlybequrvfohgriraabjtbaruraprur') # doctest: +ELLIPSIS
- (13, -126.25233502...)
- """
- sanitised_message = sanitise(message)
- best_shift = 0
- best_fit = float('-inf')
- for shift in range(26):
- 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]))
- if fit > best_fit:
- best_fit = fit
- best_shift = shift
- logger.info('Caesar break best fit: key {0} gives fit of {1} and '
- 'decrypt starting: {2}'.format(best_shift, best_fit,
- caesar_decipher(sanitised_message, best_shift)[:50]))
- return best_shift, best_fit
-
-def affine_break(message,
- metric=norms.euclidean_distance,
- target_counts=normalised_english_counts,
- message_frequency_scaling=norms.normalise):
- """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 ' \
- 'ls umfjsd jlsi zg hfsqysxog. ls dmmdtsd mx jls bats mh bkbsf. ls ' \
- 'bfmctsd kfmyxd jls lyj, mztanamyu xmc jm clm cku tmmeaxw kj lai ' \
- 'kxd clm ckuxj.') # doctest: +ELLIPSIS
- ((15, 22, True), 0.0598745365924...)
- """
- sanitised_message = sanitise(message)
- best_multiplier = 0
- best_adder = 0
- best_one_based = True
- best_fit = float("inf")
- for one_based in [True, False]:
- for multiplier in range(1, 26, 2):
- for adder in range(26):
- plaintext = affine_decipher(sanitised_message,
- multiplier, adder, one_based)
- counts = message_frequency_scaling(frequencies(plaintext))
- fit = metric(target_counts, counts)
- 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,
- 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]))
- return (best_multiplier, best_adder, best_one_based), best_fit
-
-def keyword_break(message,
- wordlist=keywords,
- metric=norms.euclidean_distance,
- target_counts=normalised_english_counts,
- message_frequency_scaling=norms.normalise):
- """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', 1), \
- wordlist=['cat', 'elephant', 'kangaroo']) # doctest: +ELLIPSIS
- (('elephant', 1), 0.1066453448861...)
+def amsco_break(message, translist=transpositions, patterns = [(1, 2), (2, 1)],
+ fillstyles = [AmscoFillStyle.continuous,
+ AmscoFillStyle.same_each_row,
+ AmscoFillStyle.reverse_each_row],
+ fitness=Pbigrams,
+ chunksize=500):
+ """Breaks an AMSCO transposition cipher using a dictionary and
+ n-gram frequency analysis
+
+ >>> amsco_break(amsco_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']}, \
+ patterns=[(1, 2)]) # doctest: +ELLIPSIS
+ (((2, 0, 5, 3, 1, 4, 6), (1, 2), <AmscoFillStyle.continuous: 1>), -709.4646722...)
+ >>> amsco_break(amsco_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', fillpattern=(2, 1)), \
+ 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']}, \
+ patterns=[(1, 2), (2, 1)], fitness=Ptrigrams) # doctest: +ELLIPSIS
+ (((2, 0, 5, 3, 1, 4, 6), (2, 1), <AmscoFillStyle.continuous: 1>), -997.0129085...)
"""
- best_keyword = ''
- best_wrap_alphabet = True
- best_fit = float("inf")
- for wrap_alphabet in range(3):
- for keyword in wordlist:
- plaintext = keyword_decipher(message, keyword, wrap_alphabet)
- counts = message_frequency_scaling(frequencies(plaintext))
- fit = metric(target_counts, counts)
- logger.debug('Keyword break attempt using key {0} (wrap={1}) '
- 'gives fit of {2} and decrypt starting: {3}'.format(
- keyword, wrap_alphabet, fit,
+ with Pool() as pool:
+ helper_args = [(message, trans, pattern, fillstyle, fitness)
+ for trans in translist
+ for pattern in patterns
+ for fillstyle in fillstyles]
+ # Gotcha: the helper function here needs to be defined at the top level
+ # (limitation of Pool.starmap)
+ breaks = pool.starmap(amsco_break_worker, helper_args, chunksize)
+ return max(breaks, key=lambda k: k[1])
+
+def amsco_break_worker(message, transposition,
+ pattern, fillstyle, fitness):
+ plaintext = amsco_transposition_decipher(message, transposition,
+ fillpattern=pattern, fillstyle=fillstyle)
+ fit = fitness(sanitise(plaintext))
+ logger.debug('AMSCO transposition break attempt using key {0} and pattern'
+ '{1} ({2}) gives fit of {3} and decrypt starting: '
+ '{4}'.format(
+ transposition, pattern, fillstyle, 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,
- metric=norms.euclidean_distance,
- target_counts=normalised_english_counts,
- message_frequency_scaling=norms.normalise,
- chunksize=500):
- """Breaks a keyword substitution cipher using a dictionary and
+ return (transposition, pattern, fillstyle), fit
+
+
+def hill_break(message, matrix_size=2, fitness=Pletters,
+ number_of_solutions=1, chunksize=500):
+
+ all_matrices = [np.matrix(list(m))
+ for m in itertools.product([list(r)
+ for r in itertools.product(range(26), repeat=matrix_size)],
+ repeat=matrix_size)]
+ valid_matrices = [m for m, d in
+ zip(all_matrices, (int(round(linalg.det(m))) for m in all_matrices))
+ if d != 0
+ if d % 2 != 0
+ if d % 13 != 0 ]
+ with Pool() as pool:
+ helper_args = [(message, matrix, fitness)
+ for matrix in valid_matrices]
+ # Gotcha: the helper function here needs to be defined at the top level
+ # (limitation of Pool.starmap)
+ breaks = pool.starmap(hill_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 hill_break_worker(message, matrix, fitness):
+ plaintext = hill_decipher(matrix, message)
+ fit = fitness(plaintext)
+ logger.debug('Hill cipher break attempt using key {0} gives fit of '
+ '{1} and decrypt starting: {2}'.format(matrix,
+ fit, sanitise(plaintext)[:50]))
+ return matrix, fit
+
+def bifid_break_mp(message, wordlist=keywords, fitness=Pletters, max_period=10,
+ number_of_solutions=1, 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', 1), \
+ >>> bifid_break_mp(bifid_encipher('this is a test message for the ' \
+ 'keyword decipherment', 'elephant', wrap_alphabet=KeywordWrapAlphabet.from_last), \
wordlist=['cat', 'elephant', 'kangaroo']) # doctest: +ELLIPSIS
- (('elephant', 1), 0.106645344886...)
+ (('elephant', <KeywordWrapAlphabet.from_last: 2>, 0), -52.834575011...)
+ >>> bifid_break_mp(bifid_encipher('this is a test message for the ' \
+ 'keyword decipherment', 'elephant', wrap_alphabet=KeywordWrapAlphabet.from_last), \
+ wordlist=['cat', 'elephant', 'kangaroo'], \
+ number_of_solutions=2) # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
+ [(('elephant', <KeywordWrapAlphabet.from_last: 2>, 0), -52.834575011...),
+ (('elephant', <KeywordWrapAlphabet.from_largest: 3>, 0), -52.834575011...)]
"""
with Pool() as pool:
- helper_args = [(message, word, wrap, metric, target_counts,
- message_frequency_scaling)
- for word in wordlist for wrap in range(3)]
- # Gotcha: the helper function here needs to be defined at the top level
+ helper_args = [(message, word, wrap, period, fitness)
+ for word in wordlist
+ for wrap in KeywordWrapAlphabet
+ for period in range(max_period+1)]
+ # 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 min(breaks, key=lambda k: k[1])
-
-def keyword_break_worker(message, keyword, wrap_alphabet, metric, target_counts,
- message_frequency_scaling):
- plaintext = keyword_decipher(message, keyword, wrap_alphabet)
- counts = message_frequency_scaling(frequencies(plaintext))
- fit = metric(target_counts, counts)
+ breaks = pool.starmap(bifid_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 bifid_break_worker(message, keyword, wrap_alphabet, period, fitness):
+ plaintext = bifid_decipher(message, keyword, wrap_alphabet, period=period)
+ 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,
- metric=norms.euclidean_distance,
- target_counts=normalised_english_bigram_counts,
- message_frequency_scaling=norms.normalise):
- """Breaks a Scytale cipher
-
- >>> scytale_break('tfeulchtrtteehwahsdehneoifeayfsondmwpltmaoalhikotoere' \
- 'dcweatehiplwxsnhooacgorrcrcraotohsgullasenylrendaianeplscdriioto' \
- 'aek') # doctest: +ELLIPSIS
- (6, 0.092599933059...)
- """
- best_key = 0
- best_fit = float("inf")
- ngram_length = len(next(iter(target_counts.keys())))
- for key in range(1, 20):
- if len(message) % key == 0:
- plaintext = scytale_decipher(message, key)
- counts = message_frequency_scaling(frequencies(
- ngrams(sanitise(plaintext), ngram_length)))
- fit = metric(target_counts, counts)
- 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,
- metric=norms.euclidean_distance,
- target_counts=normalised_english_bigram_counts,
- message_frequency_scaling=norms.normalise,
- chunksize=500):
- """Breaks a column transposition cipher using a dictionary and
- n-gram frequency analysis
+ return (keyword, wrap_alphabet, period), fit
+
+
+def autokey_sa_break( message
+ , min_keylength=2
+ , max_keylength=20
+ , workers=10
+ , initial_temperature=200
+ , max_iterations=20000
+ , fitness=Pletters
+ , chunksize=1
+ , result_count=1
+ ):
+ """Break an autokey cipher by simulated annealing
"""
- # >>> 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...)
- # """
- ngram_length = len(next(iter(target_counts.keys())))
+ worker_args = []
+ ciphertext = sanitise(message)
+ for keylength in range(min_keylength, max_keylength+1):
+ for i in range(workers):
+ key = cat(random.choice(string.ascii_lowercase) for _ in range(keylength))
+ worker_args.append((ciphertext, key,
+ initial_temperature, max_iterations, fitness))
+
with Pool() as pool:
- helper_args = [(message, trans, columnwise, metric, target_counts, ngram_length,
- message_frequency_scaling)
- for trans in translist.keys() for columnwise 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 min(breaks, key=lambda k: k[1])
-column_transposition_break = column_transposition_break_mp
-
-def column_transposition_break_worker(message, transposition, columnwise, metric, target_counts,
- ngram_length, message_frequency_scaling):
- plaintext = column_transposition_decipher(message, transposition, columnwise=columnwise)
- counts = message_frequency_scaling(frequencies(
- ngrams(sanitise(plaintext), ngram_length)))
- fit = metric(target_counts, counts)
- 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):
- 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)
- # pw = Pwords(segment(plaintext))
- pw = sum([log10(bigram_likelihood(b,
- normalised_english_bigram_counts,
- normalised_english_counts))
- for b in ngrams(plaintext, 2)])
- 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 pw > best_pw:
- best_transposition = transposition
- best_columnwise = columnwise
- best_pw = pw
- return (best_transposition, best_columnwise), best_pw
-
-
-def vigenere_keyword_break(message,
- wordlist=keywords,
- metric=norms.euclidean_distance,
- target_counts=normalised_english_counts,
- message_frequency_scaling=norms.normalise):
- """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', 0.15965224935...)
- """
- best_keyword = ''
- best_fit = float("inf")
- for keyword in wordlist:
- plaintext = vigenere_decipher(message, keyword)
- counts = message_frequency_scaling(frequencies(plaintext))
- fit = metric(target_counts, counts)
- 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,
- metric=norms.euclidean_distance,
- target_counts=normalised_english_counts,
- message_frequency_scaling=norms.normalise,
- 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', 0.159652249358...)
- """
- with Pool() as pool:
- helper_args = [(message, word, metric, target_counts,
- message_frequency_scaling)
- 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 min(breaks, key=lambda k: k[1])
-
-def vigenere_keyword_break_worker(message, keyword, metric, target_counts,
- message_frequency_scaling):
- plaintext = vigenere_decipher(message, keyword)
- counts = message_frequency_scaling(frequencies(plaintext))
- fit = metric(target_counts, counts)
- 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
+ breaks = pool.starmap(autokey_sa_break_worker,
+ worker_args, chunksize)
+ if result_count <= 1:
+ return max(breaks, key=lambda k: k[1])
+ else:
+ return sorted(set(breaks), key=lambda k: k[1], reverse=True)[:result_count]
+def autokey_sa_break_worker(message, key,
+ t0, max_iterations, fitness):
+
+ temperature = t0
-def vigenere_frequency_break(message,
- metric=norms.euclidean_distance,
- target_counts=normalised_english_counts,
- message_frequency_scaling=norms.normalise):
- """Breaks a Vigenere cipher with frequency analysis
+ dt = t0 / (0.9 * max_iterations)
+
+ plaintext = autokey_decipher(message, key)
+ current_fitness = fitness(plaintext)
+ current_key = key
- >>> 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."), 'florence')) # doctest: +ELLIPSIS
- ('florence', 0.077657073...)
- """
- 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)
- counts = message_frequency_scaling(frequencies(plaintext))
- fit = metric(target_counts, counts)
- 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,
- metric=norms.euclidean_distance,
- target_counts=normalised_english_counts,
- message_frequency_scaling=norms.normalise):
- """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."), 'florence')) # doctest: +ELLIPSIS
- ('florence', 0.077657073...)
+ best_key = current_key
+ best_fitness = current_fitness
+ best_plaintext = plaintext
+
+ # print('starting for', max_iterations)
+ for i in range(max_iterations):
+ swap_pos = random.randrange(len(current_key))
+ swap_char = random.choice(string.ascii_lowercase)
+
+ new_key = current_key[:swap_pos] + swap_char + current_key[swap_pos+1:]
+
+ plaintext = autokey_decipher(message, new_key)
+ new_fitness = fitness(plaintext)
+ try:
+ sa_chance = math.exp((new_fitness - current_fitness) / temperature)
+ except (OverflowError, ZeroDivisionError):
+ # print('exception triggered: new_fit {}, current_fit {}, temp {}'.format(new_fitness, current_fitness, temperature))
+ sa_chance = 0
+ if (new_fitness > current_fitness or random.random() < sa_chance):
+ # logger.debug('Simulated annealing: iteration {}, temperature {}, '
+ # 'current alphabet {}, current_fitness {}, '
+ # 'best_plaintext {}'.format(i, temperature, current_alphabet,
+ # current_fitness, best_plaintext[:50]))
+
+ # logger.debug('new_fit {}, current_fit {}, temp {}, sa_chance {}'.format(new_fitness, current_fitness, temperature, sa_chance))
+# print(new_fitness, new_key, plaintext[:100])
+ current_fitness = new_fitness
+ current_key = new_key
+
+ if current_fitness > best_fitness:
+ best_key = current_key
+ best_fitness = current_fitness
+ best_plaintext = plaintext
+ if i % 500 == 0:
+ logger.debug('Simulated annealing: iteration {}, temperature {}, '
+ 'current key {}, current_fitness {}, '
+ 'best_plaintext {}'.format(i, temperature, current_key,
+ current_fitness, plaintext[:50]))
+ temperature = max(temperature - dt, 0.001)
+
+# print(best_key, best_fitness, best_plaintext[:70])
+ return best_key, best_fitness # current_alphabet, current_fitness
+
+
+def pocket_enigma_break_by_crib(message, wheel_spec, crib, crib_position):
+ """Break a pocket enigma using a crib (some plaintext that's expected to
+ be in a certain position). Returns a list of possible starting wheel
+ positions that could produce the crib.
+
+ >>> pocket_enigma_break_by_crib('kzpjlzmoga', 1, 'h', 0)
+ ['a', 'f', 'q']
+ >>> pocket_enigma_break_by_crib('kzpjlzmoga', 1, 'he', 0)
+ ['a']
+ >>> pocket_enigma_break_by_crib('kzpjlzmoga', 1, 'll', 2)
+ ['a']
+ >>> pocket_enigma_break_by_crib('kzpjlzmoga', 1, 'l', 2)
+ ['a']
+ >>> pocket_enigma_break_by_crib('kzpjlzmoga', 1, 'l', 3)
+ ['a', 'j', 'n']
+ >>> pocket_enigma_break_by_crib('aaaaa', 1, 'l', 3)
+ []
"""
- 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 = beaufort_decipher(sanitised_message, key)
- counts = message_frequency_scaling(frequencies(plaintext))
- fit = metric(target_counts, counts)
- 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
-
+ pe = PocketEnigma(wheel=wheel_spec)
+ possible_positions = []
+ for p in string.ascii_lowercase:
+ pe.set_position(p)
+ plaintext = pe.decipher(message)
+ if plaintext[crib_position:crib_position+len(crib)] == crib:
+ possible_positions += [p]
+ return possible_positions
def plot_frequency_histogram(freqs, sort_key=None):
- x = range(len(freqs.keys()))
- y = [freqs[l] for l in sorted(freqs.keys(), key=sort_key)]
+ x = range(len(freqs))
+ y = [freqs[l] for l in sorted(freqs, key=sort_key)]
f = plt.figure()
ax = f.add_axes([0.1, 0.1, 0.9, 0.9])
ax.bar(x, y, align='center')
ax.set_xticks(x)
- ax.set_xticklabels(sorted(freqs.keys(), key=sort_key))
+ ax.set_xticklabels(sorted(freqs, key=sort_key))
f.show()
if __name__ == "__main__":
import doctest
doctest.testmod()
-
projects / cipher-tools.git / blobdiff