图像上的AES加密

Question

from hashlib import md5
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):
        password = key.encode('utf-8')
        self.key = md5(password).digest()

    def encrypt(self, data):
        vector = b'0123456789ABCDEF'
        # vector = get_random_bytes(AES.block_size)
        # .encrypt(pad(message, BLOCK_SIZE))
        encryption_cipher = AES.new(self.key, AES.MODE_CBC, vector)
        return vector + encryption_cipher.encrypt(pad(data,  AES.block_size))

    def decrypt(self, data):
        file_vector = data[:AES.block_size]
        decryption_cipher = AES.new(self.key, AES.MODE_CBC, file_vector)
        return  unpad(decryption_cipher.decrypt(data[AES.block_size:]),  AES.block_size)

我有一个用于AES加密的代码块，如果我更改键的长度，那意味着如果我采用16个字节的密钥长度，它将自动执行AES128，反之亦然？