Test of AES128 with python3

test_aes128.py

#!/usr/bin/env python3

from Crypto.Cipher import AES
import hashlib
import os

# message to crypt with AES-128
text = 'the secret message'

# define 128-bit key from a text password
tx_key_128 = hashlib.md5(b'password').digest()

#  initialization vector
tx_iv = os.urandom(16)

# text to crypt must be modulo 16 sized: add \x00 padding
ptxt = text.encode('utf8')
ptxt += b'\x00' * (16 - len(ptxt) % 16)

# do encrypt job
encryptor = AES.new(tx_key_128, AES.MODE_CBC, IV=tx_iv)
tx_ctxt = encryptor.encrypt(ptxt)

# build message to send on public network
pub_msg = tx_iv + tx_ctxt

# read from public message
rx_key_128 = hashlib.md5(b'password').digest()
rx_iv = pub_msg[:16]
rx_ctxt = pub_msg[16:]

# do decrypt job
decryptor = AES.new(rx_key_128, AES.MODE_CBC, IV=rx_iv)
plain = decryptor.decrypt(rx_ctxt)

# remove text padding
plain = plain.rstrip(b'\x00')

# result
print(plain.decode('utf8'))