Simple Python example of AES in CBC mode.

aes-cbc.py

#!/usr/bin/env python3
#
# This is a simple script to encrypt a message using AES
# with CBC mode in Python 3.
# Before running it, you must install pycryptodome:
#
# $ python -m pip install PyCryptodome
#
# Author.: José Lopes
# Date...: 2019-06-14
# License: MIT
##


from hashlib import md5
from base64 import b64decode
from base64 import b64encode

from Crypto.Cipher import AES
from Crypto.Random import get_random_bytes
from Crypto.Util.Padding import pad, unpad


class AESCipher:
    def __init__(self, key):
        self.key = md5(key.encode('utf8')).digest()

    def encrypt(self, data):
        iv = get_random_bytes(AES.block_size)
        self.cipher = AES.new(self.key, AES.MODE_CBC, iv)
        return b64encode(iv + self.cipher.encrypt(pad(data.encode('utf-8'), 
            AES.block_size)))

    def decrypt(self, data):
        raw = b64decode(data)
        self.cipher = AES.new(self.key, AES.MODE_CBC, raw[:AES.block_size])
        return unpad(self.cipher.decrypt(raw[AES.block_size:]), AES.block_size)



msg = 'xxxxxxxxxxxxxxxxxxxxxxxx12345678'
pwd = 'Nice passphraseNice_passphrase__'
print('Encrypt:', AESCipher(pwd).encrypt(msg).decode('utf-8'))
print('Descript:', AESCipher(pwd).decrypt(cte).decode('utf-8'))

cte is not defined