This project implements python module for automatic cryptanalysis of Substitution Permutation Network ciphers by performing extensive linear and differential characteristic search and finding keybits
The project is structured as follows:
- The
cryptanalysis
directory contains the main Python module for cryptanalysis. - The
tests
directory contains unit tests for the module - The
examples
directory contains examples for using the module - The
docs
directory contains html documentation autogenerated from code doc-strings
The project can be installed directly from pip
pip install cryptanalysis
Otherwise clone and install is also viable
git clone https://github.com/deut-erium/auto-cryptanalysis.git
cd auto-cryptanalysis
pip install .
This project requires Python3.6+ and the following Python packages:
- z3-solver
- tqdm
Requirements are auto installed as a part of the installation process but
You can also install these packages using pip:
pip install -r requirements.txt
import random
import cryptanalysis
sbox_size = 6 # bits
pbox_size = sbox_size * 16 # 16 sboxes
num_rounds = 4
sbox = list(range(2**sbox_size))
pbox = list(range(pbox_size))
# random pbox and sbox
random.shuffle(sbox)
random.shuffle(pbox)
random_key = random.randint(0, (2**pbox_size) - 1)
# random spn instance whose key is unknown to us
spn = cryptanalysis.SPN(sbox, pbox, random_key, num_rounds)
d_c = cryptanalysis.differential_cryptanalysis.DifferentialCryptanalysis(sbox, pbox, num_rounds+1)
# override batch_encrypt with the oracle
max_num_encryptions = 50000
def batch_encrypt(plaintexts):
return [spn.encrypt(i) for i in plaintexts]
d_c.batch_encrypt = batch_encrypt
differential_characteristics = d_c.characteristic_searcher.search_exclusive_masks()
last_round_key_blocks = d_c.find_last_roundkey(differential_characteristics, max_num_encryptions//16)
print("recovered last round key:",last_round_key_blocks)
print("original last round key:",d_c.int_to_list(spn.round_keys[-1]))
You can run the tests using the following command:
python -m unittest discover
Read the documentation
Autogenerated documentation from code doc-strings can be found under docs
Please feel free to submit pull requests or create issues if you find any bugs or have any suggestions for improvements.
List of ideas to implement/TODO is present in CONTRIBUTING.md
This project is licensed under the GPL License.