AES-python

AES with encryption and decryption for files using 128 bit key size

Project developed with Python version 3.6.8 and numpy version 1.18.1

You can find an encryption key and files to be encrypted in the file fot test directory.

How to use it

Create a file for the key

First, you need to create a texte file and write your key in it:

/!\The key size must be 128 bits, therefore, if you enter a longer key, only the first 32 bytes will be used for the key.

Launch main.pyw

Then launch the file main.pyw and click on "ouvrir" in the frame "Clé de chiffrement" You can check if your key loaded correctly in the "key value (decimal)" Entry box

Encrypt file

To encrypt an file, go to the "Chiffrement" frame. Click on "Ouvrir" and select your file, then, click on "Chiffrer" and choose where to save the encrypted file. When the encryption is complete, a binary file is created, this is your encrypted file.

Decrypt file

To decrypt file, go to the "Déchiffrement" frame. Click on "Ouvrir" and select the file corresponding to the encrypted file, then, click on "Déchiffrer" and choose were to save the decrypted file. /!\ You must specify the extension of your file when you save it.

Code structure

You can find the code in the src folder

CF_Multi.py

Multiplication by Galois field for MixColumns functions

Chiffrement_AES.py

Rijndael encryption functions

crypt_decrypt_fichier

Functions to encrypt and decrypt files

Dechiffrement_AES.py

Rijndael decryption functions

main.py

User interface to encrypt and decrypt files

Matrices.py

Contain the Sbox, InvSbox and Rcon matrix

MiseEnForme.py

Contain functions to convert String to list and list to numpy array with type uint8

Operation_cle.py

AddRounkey operation, Keyschedule and KeyExpansion to calculate new key for each round

About encryption

The padding used is PKCS#7.

The next updates will add other block cipher mode of operation such as CBC and CFB mode.