# 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)
+
+def index_of_coincidence(text):
+ stext = sanitise(text)
+ counts = collections.Counter(stext)
+ denom = len(stext) * (len(text) - 1) / 26
+ return (
+ sum(max(counts[l] * counts[l] - 1, 0) for l in string.ascii_lowercase)
+ /
+ denom
+ )
+
+
transpositions = collections.defaultdict(list)
for word in keywords:
transpositions[transpositions_of(word)] += [word]
wrap_alphabet, fit, sanitise(plaintext)[:50]))
return (keyword, wrap_alphabet), fit
-def monoalphabetic_break_hillclimbing(message, max_iterations=10000000,
- alphabet=None, fitness=Pletters):
- ciphertext = unaccent(message).lower()
- if not alphabet:
- alphabet = list(string.ascii_lowercase)
- random.shuffle(alphabet)
- alphabet = cat(alphabet)
- return monoalphabetic_break_hillclimbing_worker(ciphertext, alphabet,
- max_iterations, fitness)
-
-def monoalphabetic_break_hillclimbing_mp(message, workers=10,
- max_iterations = 10000000, alphabet=None, fitness=Pletters, chunksize=1):
+# def monoalphabetic_break_hillclimbing(message, max_iterations=10000000,
+# alphabet=None, fitness=Pletters):
+# ciphertext = unaccent(message).lower()
+# if not alphabet:
+# alphabet = list(string.ascii_lowercase)
+# random.shuffle(alphabet)
+# alphabet = cat(alphabet)
+# return monoalphabetic_break_hillclimbing_worker(ciphertext, alphabet,
+# max_iterations, fitness)
+
+# def monoalphabetic_break_hillclimbing_mp(message, workers=10,
+# max_iterations = 10000000, alphabet=None, fitness=Pletters, chunksize=1):
+# worker_args = []
+# ciphertext = unaccent(message).lower()
+# for i in range(workers):
+# if alphabet:
+# this_alphabet = alphabet
+# else:
+# this_alphabet = list(string.ascii_lowercase)
+# random.shuffle(this_alphabet)
+# this_alphabet = cat(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)
+# 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(best_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[:50])
+# return best_alphabet, best_fitness
+
+
+def monoalphabetic_break_hillclimbing(message,
+ max_iterations=20000,
+ plain_alphabet=None,
+ cipher_alphabet=None,
+ fitness=Pletters, chunksize=1):
+ return simulated_annealing_break(message,
+ workers=1,
+ initial_temperature=0,
+ max_iterations=max_iterations,
+ plain_alphabet=plain_alphabet,
+ cipher_alphabet=cipher_alphabet,
+ fitness=fitness, chunksize=chunksize)
+
+
+def monoalphabetic_break_hillclimbing_mp(message,
+ workers=10,
+ max_iterations=20000,
+ plain_alphabet=None,
+ cipher_alphabet=None,
+ fitness=Pletters, chunksize=1):
+ return simulated_annealing_break(message,
+ workers=workers,
+ initial_temperature=0,
+ max_iterations=max_iterations,
+ plain_alphabet=plain_alphabet,
+ cipher_alphabet=cipher_alphabet,
+ fitness=fitness, chunksize=chunksize)
+
+
+def simulated_annealing_break(message, workers=10,
+ initial_temperature=200,
+ max_iterations=20000,
+ plain_alphabet=None,
+ cipher_alphabet=None,
+ fitness=Pletters, chunksize=1):
worker_args = []
- ciphertext = unaccent(message).lower()
+ ciphertext = sanitise(message)
for i in range(workers):
- if alphabet:
- this_alphabet = alphabet
- else:
- this_alphabet = list(string.ascii_lowercase)
- random.shuffle(this_alphabet)
- this_alphabet = cat(this_alphabet)
- worker_args.append((ciphertext, this_alphabet, max_iterations, fitness))
+ if not plain_alphabet:
+ plain_alphabet = string.ascii_lowercase
+ if not cipher_alphabet:
+ cipher_alphabet = list(string.ascii_lowercase)
+ random.shuffle(cipher_alphabet)
+ cipher_alphabet = cat(cipher_alphabet)
+ worker_args.append((ciphertext, plain_alphabet, cipher_alphabet,
+ initial_temperature, max_iterations, fitness))
with Pool() as pool:
- breaks = pool.starmap(monoalphabetic_break_hillclimbing_worker,
+ breaks = pool.starmap(simulated_annealing_break_worker,
worker_args, chunksize)
return max(breaks, key=lambda k: k[1])
-def monoalphabetic_break_hillclimbing_worker(message, alphabet,
- max_iterations, fitness):
+
+def simulated_annealing_break_worker(message, plain_alphabet, cipher_alphabet,
+ t0, max_iterations, fitness):
def swap(letters, i, j):
if i > j:
i, j = j, i
else:
return (letters[:i] + letters[j] + letters[i+1:j] + letters[i] +
letters[j+1:])
- best_alphabet = alphabet
- best_fitness = float('-inf')
+
+ temperature = t0
+
+ dt = t0 / (0.9 * max_iterations)
+
+ current_alphabet = cipher_alphabet
+ alphabet = current_alphabet
+ cipher_translation = ''.maketrans(current_alphabet, plain_alphabet)
+ plaintext = message.translate(cipher_translation)
+ current_fitness = fitness(plaintext)
+
+ best_alphabet = current_alphabet
+ best_fitness = current_fitness
+ best_plaintext = plaintext
+
+ # print('starting for', max_iterations)
for i in range(max_iterations):
- alphabet = swap(alphabet, random.randrange(26), random.randrange(26))
- cipher_translation = ''.maketrans(string.ascii_lowercase, alphabet)
+ swap_a = random.randrange(26)
+ swap_b = (swap_a + int(random.gauss(0, 4))) % 26
+ alphabet = swap(current_alphabet, swap_a, swap_b)
+ cipher_translation = ''.maketrans(alphabet, plain_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
+ new_fitness = fitness(plaintext)
+ try:
+ sa_chance = math.exp((new_fitness - current_fitness) / temperature)
+ except (OverflowError, ZeroDivisionError):
+ # print('exception triggered: new_fit {}, current_fit {}, temp {}'.format(new_fitness, current_fitness, temperature))
+ sa_chance = 0
+ if (new_fitness > current_fitness or random.random() < sa_chance):
+ # logger.debug('Simulated annealing: iteration {}, temperature {}, '
+ # 'current alphabet {}, current_fitness {}, '
+ # 'best_plaintext {}'.format(i, temperature, current_alphabet,
+ # current_fitness, best_plaintext[:50]))
+
+ # logger.debug('new_fit {}, current_fit {}, temp {}, sa_chance {}'.format(new_fitness, current_fitness, temperature, sa_chance))
+ current_fitness = new_fitness
+ current_alphabet = alphabet
+
+ if current_fitness > best_fitness:
+ best_alphabet = current_alphabet
+ best_fitness = current_fitness
+ best_plaintext = plaintext
+ if i % 500 == 0:
+ logger.debug('Simulated annealing: iteration {}, temperature {}, '
+ 'current alphabet {}, current_fitness {}, '
+ 'best_plaintext {}'.format(i, temperature, current_alphabet,
+ current_fitness, plaintext[:50]))
+ temperature = max(temperature - dt, 0.001)
+
+ return best_alphabet, best_fitness # current_alphabet, current_fitness
def vigenere_keyword_break_mp(message, wordlist=keywords, fitness=Pletters,
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
+ """Breaks a railfence cipher using a matrix of given rank and letter frequencies
"""
return (keyword, wrap_alphabet, period), fit
+def autokey_sa_break( message
+ , min_keylength=2
+ , max_keylength=20
+ , workers=10
+ , initial_temperature=200
+ , max_iterations=20000
+ , fitness=Pletters
+ , chunksize=1
+ , result_count=1
+ ):
+ """Break an autokey cipher by simulated annealing
+ """
+ worker_args = []
+ ciphertext = sanitise(message)
+ for keylength in range(min_keylength, max_keylength+1):
+ for i in range(workers):
+ key = cat(random.choice(string.ascii_lowercase) for _ in range(keylength))
+ worker_args.append((ciphertext, key,
+ initial_temperature, max_iterations, fitness))
+
+ with Pool() as pool:
+ breaks = pool.starmap(autokey_sa_break_worker,
+ worker_args, chunksize)
+ if result_count <= 1:
+ return max(breaks, key=lambda k: k[1])
+ else:
+ return sorted(set(breaks), key=lambda k: k[1], reverse=True)[:result_count]
+
+
+def autokey_sa_break_worker(message, key,
+ t0, max_iterations, fitness):
+
+ temperature = t0
+
+ dt = t0 / (0.9 * max_iterations)
+
+ plaintext = autokey_decipher(message, key)
+ current_fitness = fitness(plaintext)
+ current_key = key
+
+ best_key = current_key
+ best_fitness = current_fitness
+ best_plaintext = plaintext
+
+ # print('starting for', max_iterations)
+ for i in range(max_iterations):
+ swap_pos = random.randrange(len(current_key))
+ swap_char = random.choice(string.ascii_lowercase)
+
+ new_key = current_key[:swap_pos] + swap_char + current_key[swap_pos+1:]
+
+ plaintext = autokey_decipher(message, new_key)
+ new_fitness = fitness(plaintext)
+ try:
+ sa_chance = math.exp((new_fitness - current_fitness) / temperature)
+ except (OverflowError, ZeroDivisionError):
+ # print('exception triggered: new_fit {}, current_fit {}, temp {}'.format(new_fitness, current_fitness, temperature))
+ sa_chance = 0
+ if (new_fitness > current_fitness or random.random() < sa_chance):
+ # logger.debug('Simulated annealing: iteration {}, temperature {}, '
+ # 'current alphabet {}, current_fitness {}, '
+ # 'best_plaintext {}'.format(i, temperature, current_alphabet,
+ # current_fitness, best_plaintext[:50]))
+
+ # logger.debug('new_fit {}, current_fit {}, temp {}, sa_chance {}'.format(new_fitness, current_fitness, temperature, sa_chance))
+# print(new_fitness, new_key, plaintext[:100])
+ current_fitness = new_fitness
+ current_key = new_key
+
+ if current_fitness > best_fitness:
+ best_key = current_key
+ best_fitness = current_fitness
+ best_plaintext = plaintext
+ if i % 500 == 0:
+ logger.debug('Simulated annealing: iteration {}, temperature {}, '
+ 'current key {}, current_fitness {}, '
+ 'best_plaintext {}'.format(i, temperature, current_key,
+ current_fitness, plaintext[:50]))
+ temperature = max(temperature - dt, 0.001)
+
+# print(best_key, best_fitness, best_plaintext[:70])
+ return best_key, best_fitness # current_alphabet, current_fitness
+
+
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
projects / cipher-tools.git / blobdiff