def test_challenge_3(self):
""" Challenge 3: Find xor cipher byte """
input = '1b37373331363f78151b7f2b783431333d78397828372d363c78373e783a393b3736'
input_bytes = conv.hex_to_bytes(input)
b, output, score = xortools.solve_xor_block(input_bytes)
self.assertEqual(b, 88)
self.assertEqual(output, b"Cooking MC's like a pound of bacon")
def test_challenge_19(self):
""" Challenge 19: Break fixed-nonce CTR """
key = aestools.random_key(16)
nonce = bytes(8)
input_file = open('files/19.txt', 'r')
lines = [conv.base_64_to_bytes(line.rstrip()) for line in input_file]
input_file.close()
encrypted_lines = [aestools.do_ctr(line, key, nonce) for line in lines]
index = 0
probable_bytes = bytearray()
while(True):
rotated = "".join([chr(line[index]) if index < len(line) else '' for line in encrypted_lines])
b, all, score = xortools.solve_xor_block(bytes(rotated, 'utf-8'))
probable_bytes.append(b)
index += 1
if len(rotated) == 0: break
for line in encrypted_lines:
close = xortools.xor_bytes(line, bytes(probable_bytes[0 : len(line)]))
readable = " ".join([chr(b) if b in range(32, 127) else 'X' for b in close])
