X-Git-Url: https://git.njae.me.uk/?a=blobdiff_plain;f=cipherbreak.py;h=3639da5c68c1d32621b73129c9495a91ae73539c;hb=c27359845106e917cb86d50c04bb9466d6610077;hp=6e08f49b05f327e24481734b22d115f727048dd9;hpb=a9764544656d294f1079844c158a3c5df838115b;p=cipher-training.git diff --git a/cipherbreak.py b/cipherbreak.py index 6e08f49..3639da5 100644 --- a/cipherbreak.py +++ b/cipherbreak.py @@ -37,22 +37,22 @@ def frequencies(text): [('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 ' \ @@ -120,10 +121,10 @@ def affine_break(message, fitness=Pletters): 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, + 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 @@ -145,16 +146,16 @@ def keyword_break(message, wordlist=keywords, fitness=Pletters): 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 @@ -168,12 +169,12 @@ def keyword_break_mp(message, wordlist=keywords, fitness=Pletters, chunksize=500 (('elephant', ), -52.834575011...) """ with Pool() as pool: - helper_args = [(message, word, wrap, fitness) - for word in wordlist + 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 + # 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): @@ -215,7 +216,8 @@ 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): @@ -443,4 +445,3 @@ def plot_frequency_histogram(freqs, sort_key=None): if __name__ == "__main__": import doctest doctest.testmod() -