def test_challenge_17(self):

""" Challenge 17: CBC padding oracle """

input_file = open('files/17.txt', 'r')

lines = [conv.base_64_to_bytes(line.rstrip()) for line in input_file]

input_file.close()

cipher, iv = aestools.provide_cbc_ecrypted()

self.assertTrue(aestools.is_valid_padding(cipher, iv))

cracked = aestools.break_cbc_using_padding(aestools.is_valid_padding, cipher, iv)

self.assertTrue(cracked in lines)

def test_challenge_18(self):

""" Challenge 18: CTR Encryption """

test = 'L77na/nrFsKvynd6HzOoG7GHTLXsTVu9qvY/2syLXzhPweyyMTJULu/6/kXX0KSvoOLSFQ=='

key = "YELLOW SUBMARINE"

nonce = bytes(8)

self.assertEqual(b"Yo, VIP Let's kick it Ice, Ice, baby Ice, Ice, baby ", aestools.do_ctr(conv.base_64_to_bytes(test), key, nonce))

roundtrip_input = conv.base_64_to_bytes(aestools.TEXT)

roundtrip_encrypt = aestools.do_ctr(roundtrip_input, key, nonce)

self.assertEqual(roundtrip_input, aestools.do_ctr(roundtrip_encrypt, key, nonce))

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])

#print(readable)

# no need to automate everything, from here i would manually adjust bytes

def test_challenge_20(self):

""" Challenge 20: Break fixed-nonce CTR Statistically """

key = aestools.random_key(16)

nonce = bytes(8)

input_file = open('files/20.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]

min_length = min([len(line) for line in encrypted_lines])

concatted = b''.join([line[0:min_length] for line in encrypted_lines])

test = xortools.breakxor(concatted, min_length)

#print(test)

# this is even closer than the last one, still would require tweaking a couple bytes

def test_challenge_22(self):

""" Challenge 22: MT seed finding, uncomment to run """

#start_time = int(round(time.time() * 1000))

#first_rand = mt.wait_seed_wait_rand()

#end_time = int(round(time.time() * 1000))

#for seed in range(start_time, end_time):

# generator = mt.MT19937(seed)

# if(generator.extract_number() == first_rand):

# print("Found seed: ")

# print(seed)

# break

def test_challenge_23(self):

""" Challenge 23: Clone MT """

seed = int(round(time.time() * 1000))

original = mt.MT19937(seed)

cloned = mt.clone_mt(original)

# they should be different objects

self.assertNotEqual(original, cloned)

#run the clone until it catches up to the original, if needed

next_number = original.extract_number()

cloned_number = cloned.extract_number()

timeout = 0

while(next_number != cloned_number):

cloned_number = cloned.extract_number()

timeout += 1

if(timeout > 1000):

raise Exception('cloned twister couldnt catch up to original')

# check next few numbers of each to make sure they're equal

for i in range(5):