def test_ecb_padding(self):
key = "My secret key"
encrypter = get_ecb_encrypter(key)
encrypt_image_file(SOURCE_IMAGE_42, encrypter, "examples/ecb-42.png")
decrypter = get_ecb_decrypter(key)
decrypt_image_file("examples/ecb-42.png", decrypter, "examples/ecb-42-d.png")
difference = _get_images_difference(SOURCE_IMAGE_42, "examples/ecb-42-d.png")
self.assertTrue(difference <= TARGET_DIFFERENCE_42)
def test_make_caesar(self):
offset = 128
caesar_encrypter = lambda image: bytes([(pixel + offset) % 0xff for pixel in image])
caesar_decrypter = lambda image: bytes([(pixel - offset) % 0xff for pixel in image])
encrypt_image_file(SOURCE_IMAGE_TUX, caesar_encrypter, "examples/caesar.png")
decrypt_image_file("examples/caesar.png", caesar_decrypter, "examples/caesar-d.png")
difference = _get_images_difference(SOURCE_IMAGE_TUX, "examples/caesar-d.png")
self.assertTrue(difference == 0.00)
def test_make_otp(self):
cipher = get_stream_cipher(seed="My secret seed")
encrypt_image_file(SOURCE_IMAGE_TUX, cipher, "examples/otp.png")
# Decrypt correctly
decrypt_image_file("examples/otp.png", cipher, "examples/otp-d.png")
difference = _get_images_difference(SOURCE_IMAGE_TUX, "examples/otp-d.png")
self.assertTrue(difference <= TARGET_DIFFERENCE_TUX)
# Use a wrong cipher to decrypt
cipher = get_stream_cipher(seed="Not my secret seed")
decrypt_image_file("examples/otp.png", cipher, "examples/otp-d.png")
difference = _get_images_difference(SOURCE_IMAGE_TUX, "examples/otp-d.png")
self.assertTrue(difference > TARGET_DIFFERENCE_TUX)
def test_sanity(self):
invert = lambda x: bytes([255 - y for y in x])
image = load_image(SOURCE_IMAGE_TUX)
original = image.b
inverted = encrypt_image(image, invert)
self.assertTrue(original != inverted.b)
inverted = decrypt_image(image, invert)
self.assertTrue(original == inverted.b)
key = "My secret key"
encrypter = get_ecb_encrypter(key)
encrypt_image_file(SOURCE_IMAGE_TUX, encrypter, "examples/ecb.png")
# Decrypt correctly
decrypter = get_ecb_decrypter(key)
decrypt_image_file("examples/ecb.png", decrypter, "examples/ecb-d.png")
difference = _get_images_difference(SOURCE_IMAGE_TUX, "examples/ecb-d.png")
self.assertTrue(difference <= TARGET_DIFFERENCE_TUX)
# Use a wrong decrypter
decrypter = get_ecb_decrypter("Some other key")
decrypt_image_file("examples/ecb.png", decrypter, "examples/ecb-x.png")
difference = _get_images_difference(SOURCE_IMAGE_TUX, "examples/ecb-x.png")
self.assertTrue(difference > TARGET_DIFFERENCE_TUX)
def test_make_shorter_invert(self):
inverter = lambda image: [0xff - pixel for pixel in image]
encrypt_image_file(SOURCE_IMAGE_TUX, inverter, "examples/inverted.png")
decrypt_image_file("examples/inverted.png", inverter, "examples/inverted-d.png")
difference = _get_images_difference(SOURCE_IMAGE_TUX, "examples/inverted-d.png")
self.assertTrue(difference == 0.00)