def detect_aes_mode(encrypt_fn):
""" Detect if an encryption function is encrypting using ECB mode or CBC mode
:param encrypt_fn: Encryption function to submit plaintexts to
:return: AesMode.ECB or AesMode.CBC
"""
# Encrypt a single byte across multiple blocks. If the function is using ECB there will be repeating
# cipertext blocks.
plaintext = 'A' * 1024
ciphertext = encrypt_fn(plaintext)
if set1.detect_aes_ecb([ciphertext]):
return AesMode.ECB
else:
return AesMode.CBC
def test_detect_aes_ecb_mode(self):
with open('8.txt') as f:
lines = f.readlines()
deciphered = set1.detect_aes_ecb(lines)
self.assertEqual(deciphered, [133])
def test_detect_aes_ecb():
""" Set 1 Challenge 8 """
assert set1.detect_aes_ecb(open(SCRIPT_DIR + 'test_data/1_8.txt', 'r').read().splitlines()) == [132]
