def test_decrypt(self):
cipher = Vigenere()
cipher_text = "eylzkbzvpgwfafroeujhkgvlctwjlfvwtdzacvchkedhncxupmeajucdcgmscs"
open_text = cipher.decrypt(cipher_text, "password")
expected = "pythonisageneralpurposeinterpretedhighlevelprogramminglanguage"
self.assertEqual(open_text, expected)
self.assertEqual(cipher.decrypt("", "a"), "")
class VigenereBruteForce(object):
"""Cryptanalysis method for Vigenere cipher"""
def __init__(self):
super(VigenereBruteForce, self).__init__()
self.max_key_len = 10
self.caesar_cracker = TriangleAttack()
self.vigenere = Vigenere()
def crack(self, cipher_text, langstats):
key_text = self._get_possible_keys(cipher_text, langstats)
return langstats.most_meaningful(key_text)
def _get_possible_keys(self, cipher_text, langstats):
for i in range(2, self.max_key_len + 1):
partition = self._partition_text(cipher_text, i)
key = "".join(self.caesar_cracker.crack(v, langstats) for v in partition)
yield key, self.vigenere.decrypt(cipher_text, key)
def _partition_text(self, text, number):
classes = {x:[] for x in range(number)}
for i, char in enumerate(text):
classes[i % number].append(char)
return ("".join(v) for k, v in classes.iteritems())
class VigenereBruteForce(object):
"""Cryptanalysis method for Vigenere cipher"""
def __init__(self):
super(VigenereBruteForce, self).__init__()
self.max_key_len = 10
self.caesar_cracker = TriangleAttack()
self.vigenere = Vigenere()
def crack(self, cipher_text, langstats):
key_text = self._get_possible_keys(cipher_text, langstats)
return langstats.most_meaningful(key_text)
def _get_possible_keys(self, cipher_text, langstats):
for i in range(2, self.max_key_len + 1):
partition = self._partition_text(cipher_text, i)
key = "".join(
self.caesar_cracker.crack(v, langstats) for v in partition)
yield key, self.vigenere.decrypt(cipher_text, key)
def _partition_text(self, text, number):
classes = {x: [] for x in range(number)}
for i, char in enumerate(text):
classes[i % number].append(char)
return ("".join(v) for k, v in classes.iteritems())
