python encode/decode aes256 example

aes256cbc.py

# pip3 uninstall pycrypto
# pip3 install pycryptodome

from Crypto.Cipher import AES
import base64

BLOCK_SIZE = 16


def pad(data):
    pad = BLOCK_SIZE - len(data) % BLOCK_SIZE
    return data + pad * chr(pad)


def unpad(padded):
    pad = ord(chr(padded[-1]))
    return padded[:-pad]


def _encrypt(data, password):
    key, iv = get_key_iv(password)
    data = pad(data)
    aes = AES.new(key, AES.MODE_CBC, iv[:16])
    encrypted = aes.encrypt(data)
    return base64.urlsafe_b64encode(encrypted)


def _decrypt(data, key, iv):
    data = base64.b64decode(data)
    key = base64.b64decode(key)
    iv = base64.b64decode(iv)
    aes = AES.new(key, AES.MODE_CBC, iv[:16])
    return unpad(aes.decrypt(data))


# node -e 'console.log(crypto.randomBytes(32).toString("base64"))'
key = "IC7gTKZB6Ozb20mdRAHCFzJl2XsaU7nq3XFJoQqoGk0="  # secret environment variable

# node -e 'console.log(crypto.randomBytes(16).toString("base64"))'
iv = "KdLAu6oKOoffRURx9u0Ulw==" # already stored in the database

encoded_username = "Lx8aSNQeBACvbrNjycVyVg==" # already stored in the database
encoded_password = "4qxTadTDeQ2pzhSl83MicA==" # already stored in the database

decoded_username = _decrypt(encoded_username, key, iv).decode('utf8')
decoded_password = _decrypt(encoded_password, key, iv).decode('utf8')

print(decoded_username, decoded_password)