def get_vigenere_key_score(ciphertext, keysize, compare_blocks=4):
"""returns the score for this keysize on this text"""
hdist = 0
blocks = vigenere_blocks(ciphertext, keysize, compare_blocks)
comparisons = 0
for b1, b2 in itertools.combinations(blocks, 2):
hdist += crypt_utils.hamming_distance(b1, b2)
comparisons += 1
hdist = hdist / comparisons
return hdist / keysize
def test_hamming_distance(self):
s1 = "this is a test"
s2 = "wokka wokka!!!"
h_dist = crypt_utils.hamming_distance(s1, s2)
self.assertEqual(h_dist, 37)
