project-des 0.1.1

Warning: This implementation is intended for self learning purposes only and should not be used for real-world security.

About

• Author: shrimp2845
• Version: 0.1.0
• License: MIT

This is an educational Python implementation of the Data Encryption Standard (DES). This project breaks down the complex Feistel network into human-readable modules following the official NIST specifications, and supports ECB and CBC modes for real file encryption.

Installation & Usage

install

Requires Python 3.10+

pip install project-des

usage

python -c "from project_DES import DES; cipher = DES(b'12345678'); print(cipher.encrypt(b'data').hex())"

Docs

class initialize
----------------------
project_DES.DES(key, mode='ECB')

key 
-> 8 bytes or key file name 
containing an encryption key,
if key is str, it extract 
first 8 bytes in the file

mode
-> optional, block cipher mode of 
operation that used,ECB and CBC 
available in current version


methods
----------------------

encrypt(data: bytes) -> bytes, 
decrypt(data: bytes) -> bytes
-> return encrypt/decrypt bytes data

encrypt_file(name: str, new_name: str), 
decrypt_file(name: str, new_name: str) 
-> encrypt/decrypt target file 'name' 
and save it as 'new_name'

get_key(), get_mode()
-> get current using key/mode of 
operation

change_key(key: str or bytes),
change_mode(mode: str)
-> change current using key/mode of 
operation

Examples

Project provides two examples: string_cipher.py & file_cipher.py

you can find samples of file_cipher.py at: ecb_sample & cbc_sample

explanation for samples

mumei.jpg: plaintext file

mumei.bin: encrypt mumei.jpg with key ‘berries’ and mode ECB

mumei_correct_decrypt.jpg: decrypt mumei.bin with key ‘berries’ and mode ECB

mumei_wrong_decrypt.jpg: decrypt mumei.bin with key ‘friend’ and mode ECB

ina.jpg: plaintext file

ina.bin: encrypt ina.jpg with key ‘takodachi’ and mode CBC

ina_correct_decrypt.jpg: decrypt ina.bin with key ‘takodachi’ and mode CBC

ina_wrong_decrypt.jpg: decrypt ina.bin with key ‘violet’ and mode CBC

Performance

This project is designed for learning and understanding how DES works rather than for practical encryption use. The implementation prioritizes readability and modular structure over performance.

As a result, encryption process is very slow. It takes nearly 2 minutes to encrypt 1MB file.