+++ /dev/null
-from utilities import *
-from language_models import *
-from enum import Enum
-from itertools import starmap, cycle
-import multiprocessing
-
-from logger import logger
-
-def vigenere_encipher(message, keyword):
- """Vigenere encipher
-
- >>> vigenere_encipher('hello', 'abc')
- 'hfnlp'
- """
- shifts = [pos(l) for l in sanitise(keyword)]
- pairs = zip(message, cycle(shifts))
- return cat([caesar_encipher_letter(l, k) for l, k in pairs])
-
-def vigenere_decipher(message, keyword):
- """Vigenere decipher
-
- >>> vigenere_decipher('hfnlp', 'abc')
- 'hello'
- """
- shifts = [pos(l) for l in sanitise(keyword)]
- pairs = zip(message, cycle(shifts))
- return cat([caesar_decipher_letter(l, k) for l, k in pairs])
-
-
-def beaufort_encipher(message, keyword):
- """Beaufort encipher
-
- >>> beaufort_encipher('inhisjournaldatedtheidesofoctober', 'arcanaimperii')
- 'sevsvrusyrrxfayyxuteemazudmpjmmwr'
- """
- shifts = [pos(l) for l in sanitise(keyword)]
- pairs = zip(message, cycle(shifts))
- return cat([unpos(k - pos(l)) for l, k in pairs])
-
-beaufort_decipher = beaufort_encipher
-
-beaufort_variant_encipher=vigenere_decipher
-beaufort_variant_decipher=vigenere_encipher
-
-
-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', -52.9472712...)
- """
- with multiprocessing.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', -307.5473096...)
- """
- def worker(message, key_length, fitness):
- splits = every_nth(sanitised_message, key_length)
- key = cat([unpos(caesar_break(s)[0]) 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_sub_break(message, fitness=Pletters):
- """Breaks one chunk of a Beaufort cipher with frequency analysis
-
- >>> beaufort_sub_break('samwpplggnnmmyaazgympjapopnwiywwomwspgpjmefwmawx' \
- 'jafjhxwwwdigxshnlywiamhyshtasxptwueahhytjwsn') # doctest: +ELLIPSIS
- (0, -117.4492...)
- >>> beaufort_sub_break('eyprzjjzznxymrygryjqmqhznjrjjapenejznawngnnezgza' \
- 'dgndknaogpdjneadadazlhkhxkryevrronrmdjnndjlo') # doctest: +ELLIPSIS
- (17, -114.9598...)
- """
- best_shift = 0
- best_fit = float('-inf')
- for key in range(26):
- plaintext = [unpos(key - pos(l)) for l in message]
- fit = fitness(plaintext)
- logger.debug('Beaufort sub break attempt using key {0} gives fit of {1} '
- 'and decrypt starting: {2}'.format(key, fit,
- plaintext[:50]))
- if fit > best_fit:
- best_fit = fit
- best_key = key
- logger.info('Beaufort sub break best fit: key {0} gives fit of {1} and '
- 'decrypt starting: {2}'.format(best_key, best_fit,
- cat([unpos(best_key - pos(l)) for l in message[:50]])))
- return best_key, best_fit
-
-
-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(message, key_length)
- key = cat([unpos(beaufort_sub_break(s)[0]) 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 beaufort_variant_frequency_break(message, max_key_length=20, fitness=Pletters):
- """Breaks a Beaufort cipher with frequency analysis
-
- >>> beaufort_variant_frequency_break(beaufort_variant_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 = cat([unpos(-caesar_break(s)[0]) for s in splits])
- plaintext = beaufort_variant_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])
-
-if __name__ == "__main__":
- import doctest
\ No newline at end of file
projects / cipher-tools.git / blobdiff