wrap_alphabet, fit, sanitise(plaintext)[:50]))
return (keyword, wrap_alphabet), fit
+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)
+
+def monoalphabetic_break_hillclimbing_mp(message, workers=10,
+ max_iterations = 10000000, 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))
+ 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(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)
+ return best_alphabet, best_fitness
+
def column_transposition_break_mp(message, translist=transpositions,
fitness=Pbigrams, chunksize=500):
return max(breaks, key=lambda k: k[1])
column_transposition_break = column_transposition_break_mp
-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)
-
-def monoalphabetic_break_hillclimbing_mp(message, workers=100,
- max_iterations = 10000000, 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))
- 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(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)
- return best_alphabet, best_fitness
-
-
def column_transposition_break_worker(message, transposition,
fillcolumnwise, emptycolumnwise, fitness):
plaintext = column_transposition_decipher(message, transposition,
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)]