DES-Python

Data Encryption Standard (DES) implemented in pure Python

Features

• Encryption and Decryption
• PKCS5 Padding
• ECB Mode of Operation
• Hex String and Bytes Object Support

Installation

Install using your Python package manager of choice:

pip install des_PurePy

Documentation

Full documentation: https://perez-herrera-luna.github.io/DES-Python/

Usage

Encrypting Hex Strings

Define a DES object while passing in your key. The key can be a hex string or a bytes object.

import des_PurePy
des = des_PurePy.DES("0x133457799bbcdff1")

You can encrypt by calling encrypt() and passing in a hex string or bytes object.

des.encrypt("0x0123456789abcdef")    # -> "0x85e813540f0ab405fdf2e174492922f8"

You can simarly decrypt by calling decrypt() and passing in a hex string or bytes object.

des.decrypt("0x85e813540f0ab405fdf2e174492922f8")    # -> "0x0123456789abcdef"

By default, encryption input is padded to a multiple of the block size (8 bytes) according to PKCS5. Inputs that are multiple blocks long are encrypted using the Electronic Code Book (ECB) mode of operation.

Encrypting Bytes Objects and Text

Inputs can be hex strings or bytes objects. The key must always be 8 bytes but the encryption input can have any size. Because of the bytes object support, with some work, you can encrypt and decrypt text.

import des_PurePy

key = b"password"
des = des_PurePy.DES(key)

ciphertext = des.encrypt(b"secret message")                 # -> "0x0d417ca7d23582bab5e2c9277f801591"
cleartext = des.decrypt(ciphertext)                         # -> "0x736563726574206d657373616765"
cleartext = bytes.fromhex(cleartext[2:]).decode("utf-8")    # -> "secret message"

Note that all input is validated so if you pass in an inapropriate input the module will raise a corresponding error.