Install by executing python setup.py install or pip install ..
Import like other package
from des import Cipher as DES, random_key, random_message
des = DES(random_key())
message = random_message()
ciphertext = des.encrypt(message)
plaintext = des.decrypt(ciphertext)
print(plaintext == message) # should be TrueImplemented 6-rounds differential attack allow to break 6 rounds of DES using differential cryptoanalisys.
Example code has been placed in des/main.py file under break_6_rounds function.
$ python -m des
Encryption/decryption
difference = 4008000004000000
plaintext = EB47DCC8CF3D1DD7
plaintext' = AB4FDCC8CB3D1DD7
key = DC89256D162916DF
difference = 0367457805008282 (same in 12%)
ciphertext = FC9CE112286E9A23
ciphertext' = FFFBA46A2D6E18A1
ciphertext = 0D6A0F43B0481DAA (final)
decrypted = EB47DCC8CF3D1DD7 (valid)
6-round attack
Valid key: [57, 32, 42, 3, 38, 6, 15, 49] # key used by DES in 6th round
Key candidate: [-1, 32, -1, -1, 0, 6, 15, 49] # potential key (-1 inform that we cannot predict value)
Key candidate: [16, 0, -1, 3, 38, 6, -1, -1] # potential key (-1 inform that we cannot predict value)
Use pytest to run prepared unit tests.
$ pytest --verbose tests/
===================================================================================================== test session starts =====================================================================================================
platform linux -- Python 3.9.0+, pytest-6.2.2, py-1.10.0, pluggy-0.13.1 -- /home/user/des-attack/venv/bin/python
cachedir: .pytest_cache
rootdir: /home/user/des-attack
collected 7 items
tests/test_des.py::test_cipher PASSED [ 14%]
tests/test_des.py::test_function_s PASSED [ 28%]
tests/test_des.py::test_linear_transformation PASSED [ 42%]
tests/test_des.py::test_key_random_generator PASSED [ 57%]
tests/test_des.py::test_plaintext_random_generator PASSED [ 71%]
tests/test_des.py::test_permutation_inverted PASSED [ 85%]
tests/test_des.py::test_sbox PASSED [100%]
====================================================================================================== 7 passed in 0.20s ======================================================================================================