X-Git-Url: https://git.njae.me.uk/?a=blobdiff_plain;f=cipherbreak.py;fp=cipherbreak.py;h=0ac8ae57f7ed11a443dfedc8366ddc51086eda8c;hb=7203ac94911556e2b4bf4caab6f5285445faed3b;hp=6e08f49b05f327e24481734b22d115f727048dd9;hpb=a17aa893114bb916b092cf47b5968ca0b2f9b6fa;p=cipher-training.git diff --git a/cipherbreak.py b/cipherbreak.py index 6e08f49..0ac8ae5 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 @@ -32,27 +35,27 @@ for word in keywords: 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 +65,7 @@ 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 +83,8 @@ 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 +95,7 @@ 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 ' \ @@ -108,73 +112,83 @@ 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, + 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', Keyword_wrap_alphabet.from_last), \ + 'keyword decipherment', 'elephant', KeywordWrapAlphabet.from_last), \ wordlist=['cat', 'elephant', 'kangaroo']) # doctest: +ELLIPSIS - (('elephant', ), -52.834575011...) + (('elephant', ), -52.834575011...) + >>> keyword_break_mp(keyword_encipher('this is a test message for the ' \ + 'keyword decipherment', 'elephant', KeywordWrapAlphabet.from_last), \ + wordlist=['cat', 'elephant', 'kangaroo'], \ + number_of_solutions=2) # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE + [(('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) - return max(breaks, key=lambda k: k[1]) + breaks = pool.starmap(keyword_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 keyword_break_worker(message, keyword, wrap_alphabet, fitness): plaintext = keyword_decipher(message, keyword, wrap_alphabet) @@ -184,30 +198,34 @@ def keyword_break_worker(message, keyword, wrap_alphabet, fitness): wrap_alphabet, fit, sanitise(plaintext)[:50])) return (keyword, wrap_alphabet), fit -def monoalphabetic_break_hillclimbing(message, max_iterations = 10000000, - fitness=Pletters): +def monoalphabetic_break_hillclimbing(message, max_iterations=10000000, + alphabet=None, fitness=Pletters): ciphertext = unaccent(message).lower() - alphabet = list(string.ascii_lowercase) - random.shuffle(alphabet) - alphabet = ''.join(alphabet) + if not alphabet: + 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=10, - max_iterations = 10000000, fitness=Pletters, chunksize=1): + max_iterations = 10000000, alphabet=None, 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)) + if alphabet: + this_alphabet = alphabet + else: + this_alphabet = list(string.ascii_lowercase) + random.shuffle(this_alphabet) + this_alphabet = ''.join(this_alphabet) + worker_args.append((ciphertext, this_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: @@ -215,7 +233,8 @@ 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): @@ -229,17 +248,94 @@ def monoalphabetic_break_hillclimbing_worker(message, alphabet, 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 +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]) +vigenere_keyword_break = vigenere_keyword_break_mp + +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, max_key_length=20, 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...) + """ + 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(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)]) + 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 " \ + "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...) + """ + 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(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)]) + return max(results, key=lambda k: k[1]) + + +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 \ + 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'], \ @@ -250,8 +346,8 @@ def column_transposition_break_mp(message, translist=transpositions, "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 \ + 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'], \ @@ -261,21 +357,21 @@ def column_transposition_break_mp(message, translist=transpositions, (((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() + 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 + # 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) + 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, +def column_transposition_break_worker(message, transposition, fillcolumnwise, emptycolumnwise, fitness): - plaintext = column_transposition_decipher(message, transposition, + plaintext = column_transposition_decipher(message, transposition, fillcolumnwise=fillcolumnwise, emptycolumnwise=emptycolumnwise) fit = fitness(sanitise(plaintext)) logger.debug('Column transposition break attempt using key {0} ' @@ -294,8 +390,8 @@ def scytale_break_mp(message, max_key_length=20, "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 \ + 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...) @@ -303,102 +399,164 @@ def scytale_break_mp(message, max_key_length=20, "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 \ + 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))] + 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 + # 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]) + 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 railfence_break(message, max_key_length=20, + fitness=Pletters, chunksize=500): + """Breaks a hill cipher using a matrix of given rank and letter frequencies - >>> 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]) -vigenere_keyword_break = vigenere_keyword_break_mp - -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 - + + sanitised_message = sanitise(message) + results = starmap(worker, [(sanitised_message, i, fitness) + for i in range(2, max_key_length+1)]) + return max(results, key=lambda k: k[1]) -def vigenere_frequency_break(message, max_key_length=20, fitness=Pletters): - """Breaks a Vigenere cipher with frequency analysis +def railfence_break(message, max_key_length=20, + fitness=Pbigrams, chunksize=500): + """Breaks a railfence cipher using a range of lengths and + n-gram 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...) + >>> railfence_break(railfence_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."), \ + 7)) # doctest: +ELLIPSIS + (7, -709.46467226...) + >>> railfence_break(railfence_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."), \ + 7), \ + fitness=Ptrigrams) # doctest: +ELLIPSIS + (7, -997.0129085...) """ - 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(message, key) + def worker(message, height, fitness): + plaintext = railfence_decipher(message, height) fit = fitness(plaintext) - return key, fit + return height, 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(2, max_key_length+1)]) return max(results, key=lambda k: k[1]) +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 -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 " \ - "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...) + >>> 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)), -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)), -997.0129085...) """ - 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(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)]) - return max(results, key=lambda k: k[1]) + with Pool() as pool: + helper_args = [(message, trans, pattern, fillstyle, fitness) + for trans in translist.keys() + 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])) + 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 pocket_enigma_break_by_crib(message, wheel_spec, crib, crib_position): @@ -443,4 +601,3 @@ def plot_frequency_histogram(freqs, sort_key=None): if __name__ == "__main__": import doctest doctest.testmod() -