X-Git-Url: https://git.njae.me.uk/?a=blobdiff_plain;f=cipherbreak.py;h=1adebe671c17fdc029d28746c67328b208d462f3;hb=e67dfbd9159645bc3621ef9f40c4d026cad7e747;hp=eae56cfc3c8560ae50f33c60b8b8d8a9e95f622f;hpb=f23ebe9e009e465a31bd0aac2a9d9cd82da642f8;p=cipher-training.git diff --git a/cipherbreak.py b/cipherbreak.py index eae56cf..1adebe6 100644 --- a/cipherbreak.py +++ b/cipherbreak.py @@ -1,12 +1,15 @@ +"""A set of functions to break the ciphers give in ciphers.py. +""" + import string import collections import norms import logging import random -from itertools import zip_longest, cycle, permutations, starmap +import math +from itertools import starmap from segment import segment from multiprocessing import Pool -from math import log10 import matplotlib.pyplot as plt @@ -26,33 +29,30 @@ 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), + [(' ', 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 @@ -62,7 +62,7 @@ def frequencies(text): def caesar_break(message, fitness=Pletters): """Breaks a Caesar cipher using frequency analysis - + >>> caesar_break('ibxcsyorsaqcheyklxivoexlevmrimwxsfiqevvmihrsasrxliwyrh' \ 'ecjsppsamrkwleppfmergefifvmhixscsymjcsyqeoixlm') # doctest: +ELLIPSIS (4, -130.849989015...) @@ -80,7 +80,8 @@ def caesar_break(message, fitness=Pletters): 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 @@ -91,7 +92,7 @@ def caesar_break(message, fitness=Pletters): 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 ' \ @@ -108,72 +109,73 @@ def affine_break(message, fitness=Pletters): 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 + """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), \ + 'keyword decipherment', 'elephant', KeywordWrapAlphabet.from_last), \ wordlist=['cat', 'elephant', 'kangaroo']) # doctest: +ELLIPSIS - (('elephant', ), -52.834575011...) + (('elephant', ), -52.834575011...) """ best_keyword = '' best_wrap_alphabet = True best_fit = float("-inf") - for wrap_alphabet in Keyword_wrap_alphabet: + for wrap_alphabet in KeywordWrapAlphabet: 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, + 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, + '{2} and decrypt starting: {3}'.format(best_keyword, best_wrap_alphabet, best_fit, sanitise( - keyword_decipher(message, best_keyword, + 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 +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), \ + 'keyword decipherment', 'elephant', KeywordWrapAlphabet.from_last), \ wordlist=['cat', 'elephant', 'kangaroo']) # doctest: +ELLIPSIS - (('elephant', ), -52.834575011...) + (('elephant', ), -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 + helper_args = [(message, word, wrap, fitness) + for word in wordlist + for wrap in KeywordWrapAlphabet] + # 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) + 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): @@ -184,61 +186,16 @@ def keyword_break_worker(message, keyword, wrap_alphabet, fitness): wrap_alphabet, fit, sanitise(plaintext)[:50])) return (keyword, wrap_alphabet), 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 monoalphabetic_break_hillclimbing(message, max_iterations = 10000000, +def monoalphabetic_break_hillclimbing(message, max_iterations=10000000, fitness=Pletters): ciphertext = unaccent(message).lower() alphabet = list(string.ascii_lowercase) random.shuffle(alphabet) alphabet = ''.join(alphabet) return monoalphabetic_break_hillclimbing_worker(ciphertext, alphabet, - max_iterations, fitness) + max_iterations, fitness) -def monoalphabetic_break_hillclimbing_mp(message, workers=100, +def monoalphabetic_break_hillclimbing_mp(message, workers=10, max_iterations = 10000000, fitness=Pletters, chunksize=1): worker_args = [] ciphertext = unaccent(message).lower() @@ -249,10 +206,10 @@ def monoalphabetic_break_hillclimbing_mp(message, workers=100, worker_args.append((ciphertext, alphabet, max_iterations, fitness)) with Pool() as pool: breaks = pool.starmap(monoalphabetic_break_hillclimbing_worker, - worker_args, chunksize) + worker_args, chunksize) return max(breaks, key=lambda k: k[1]) -def monoalphabetic_break_hillclimbing_worker(message, alphabet, +def monoalphabetic_break_hillclimbing_worker(message, alphabet, max_iterations, fitness): def swap(letters, i, j): if i > j: @@ -260,7 +217,8 @@ def monoalphabetic_break_hillclimbing_worker(message, alphabet, if i == j: return letters else: - return letters[:i] + letters[j] + letters[i+1:j] + letters[i] + letters[j+1:] + return (letters[:i] + letters[j] + letters[i+1:j] + letters[i] + + letters[j+1:]) best_alphabet = alphabet best_fitness = float('-inf') for i in range(max_iterations): @@ -274,61 +232,9 @@ def monoalphabetic_break_hillclimbing_worker(message, alphabet, return best_alphabet, best_fitness -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 - - -def vigenere_keyword_break_mp(message, wordlist=keywords, fitness=Pletters, - chunksize=500): - """Breaks a vigenere cipher using a dictionary and - frequency analysis +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'), \ @@ -336,11 +242,12 @@ def vigenere_keyword_break_mp(message, wordlist=keywords, fitness=Pletters, ('cat', -52.947271216...) """ with Pool() as pool: - helper_args = [(message, word, fitness) + helper_args = [(message, word, fitness) for word in wordlist] - # Gotcha: the helper function here needs to be defined at the top level + # 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) + 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 @@ -348,12 +255,11 @@ 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, + '{1} and decrypt starting: {2}'.format(keyword, fit, sanitise(plaintext)[:50])) return keyword, fit - def vigenere_frequency_break(message, max_key_length=20, fitness=Pletters): """Breaks a Vigenere cipher with frequency analysis @@ -373,8 +279,8 @@ def vigenere_frequency_break(message, max_key_length=20, fitness=Pletters): fit = fitness(plaintext) return key, fit sanitised_message = sanitise(message) - results = starmap(worker, [(sanitised_message, i, fitness) - for i in range(1, max_key_length+1)]) + results = starmap(worker, [(sanitised_message, i, fitness) + for i in range(1, max_key_length+1)]) return max(results, key=lambda k: k[1]) @@ -392,16 +298,16 @@ def beaufort_frequency_break(message, max_key_length=20, fitness=Pletters): """ 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]) + key = ''.join([chr(-caesar_break(s)[0] % 26 + ord('a')) + for s in splits]) plaintext = beaufort_decipher(message, key) fit = fitness(plaintext) return key, fit sanitised_message = sanitise(message) - results = starmap(worker, [(sanitised_message, i, fitness) - for i in range(1, max_key_length+1)]) + 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): x = range(len(freqs.keys())) y = [freqs[l] for l in sorted(freqs.keys(), key=sort_key)] @@ -416,4 +322,3 @@ def plot_frequency_histogram(freqs, sort_key=None): if __name__ == "__main__": import doctest doctest.testmod() -