X-Git-Url: https://git.njae.me.uk/?a=blobdiff_plain;f=cipherbreak.py;h=6e08f49b05f327e24481734b22d115f727048dd9;hb=cc7fa19db5f263d7b131bb36922d5dc13ea86a13;hp=95b5c208975c5035a2b2c2f50d5c3ebeb5f6bb8a;hpb=ee8bb0b7953e32c988f4faa72c0eb4c6cd6e4ea8;p=cipher-training.git diff --git a/cipherbreak.py b/cipherbreak.py index 95b5c20..6e08f49 100644 --- a/cipherbreak.py +++ b/cipherbreak.py @@ -2,7 +2,8 @@ import string import collections import norms import logging -from itertools import zip_longest, cycle, permutations +import random +from itertools import zip_longest, cycle, permutations, starmap from segment import segment from multiprocessing import Pool from math import log10 @@ -131,14 +132,14 @@ def keyword_break(message, wordlist=keywords, fitness=Pletters): frequency analysis >>> keyword_break(keyword_encipher('this is a test message for the ' \ - 'keyword decipherment', 'elephant', 1), \ + 'keyword decipherment', 'elephant', Keyword_wrap_alphabet.from_last), \ wordlist=['cat', 'elephant', 'kangaroo']) # doctest: +ELLIPSIS - (('elephant', 1), -52.834575011...) + (('elephant', ), -52.834575011...) """ best_keyword = '' best_wrap_alphabet = True best_fit = float("-inf") - for wrap_alphabet in range(3): + for wrap_alphabet in Keyword_wrap_alphabet: for keyword in wordlist: plaintext = keyword_decipher(message, keyword, wrap_alphabet) fit = fitness(plaintext) @@ -162,13 +163,14 @@ def keyword_break_mp(message, wordlist=keywords, fitness=Pletters, chunksize=500 frequency analysis >>> keyword_break_mp(keyword_encipher('this is a test message for the ' \ - 'keyword decipherment', 'elephant', 1), \ + 'keyword decipherment', 'elephant', Keyword_wrap_alphabet.from_last), \ wordlist=['cat', 'elephant', 'kangaroo']) # doctest: +ELLIPSIS - (('elephant', 1), -52.834575011...) + (('elephant', ), -52.834575011...) """ with Pool() as pool: helper_args = [(message, word, wrap, fitness) - for word in wordlist for wrap in range(3)] + 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) @@ -182,67 +184,88 @@ def keyword_break_worker(message, keyword, wrap_alphabet, fitness): 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 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) + +def monoalphabetic_break_hillclimbing_mp(message, workers=10, + max_iterations = 10000000, fitness=Pletters, chunksize=1): + worker_args = [] + ciphertext = unaccent(message).lower() + for i in range(workers): + alphabet = list(string.ascii_lowercase) + random.shuffle(alphabet) + alphabet = ''.join(alphabet) + worker_args.append((ciphertext, alphabet, max_iterations, fitness)) + with Pool() as pool: + breaks = pool.starmap(monoalphabetic_break_hillclimbing_worker, + worker_args, chunksize) + return max(breaks, key=lambda k: k[1]) + +def monoalphabetic_break_hillclimbing_worker(message, alphabet, + max_iterations, fitness): + def swap(letters, i, j): + if i > j: + i, j = j, i + if i == j: + return letters + else: + 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): + alphabet = swap(alphabet, random.randrange(26), random.randrange(26)) + cipher_translation = ''.maketrans(string.ascii_lowercase, alphabet) + plaintext = message.translate(cipher_translation) + if fitness(plaintext) > best_fitness: + best_fitness = fitness(plaintext) + best_alphabet = alphabet + print(i, best_alphabet, best_fitness, plaintext) + return best_alphabet, best_fitness 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, @@ -250,64 +273,56 @@ def column_transposition_break_mp(message, translist=transpositions, 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): @@ -326,6 +341,7 @@ def vigenere_keyword_break_mp(message, wordlist=keywords, fitness=Pletters, # (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) @@ -337,7 +353,7 @@ def vigenere_keyword_break_worker(message, keyword, fitness): -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 " \ @@ -349,26 +365,19 @@ def vigenere_frequency_break(message, fitness=Pletters): "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 " \ @@ -380,25 +389,44 @@ def beaufort_frequency_break(message, fitness=Pletters): "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 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) + [] + """ + 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):