+"""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
# 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 ' \
('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),
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
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
'{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]))
+ 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', <Keyword_wrap_alphabet.from_last: 2>), -52.834575011...)
+ (('elephant', <KeywordWrapAlphabet.from_last: 2>), -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)
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', <Keyword_wrap_alphabet.from_last: 2>), -52.834575011...)
+ (('elephant', <KeywordWrapAlphabet.from_last: 2>), -52.834575011...)
"""
with Pool() as pool:
helper_args = [(message, word, wrap, fitness)
for word in wordlist
- for wrap in Keyword_wrap_alphabet]
+ 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)
wrap_alphabet, fit, sanitise(plaintext)[:50]))
return (keyword, wrap_alphabet), fit
-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=10,
max_iterations = 10000000, fitness=Pletters, chunksize=1):
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:
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):
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...)
- """
- 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 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'), \
('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
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
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 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 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):
x = range(len(freqs.keys()))
y = [freqs[l] for l in sorted(freqs.keys(), key=sort_key)]
projects / cipher-training.git / blobdiff