Pad / unpad при AES / CBC шифровании

from Crypto.Cipher import AES
 
iv = bytes([0] * 16)
key = b'1234567890123456'
enc_obj = AES.new(key, AES.MODE_CBC, iv)
dec_obj = AES.new(key, AES.MODE_CBC, iv)
 
def dec(enc):
    return dec_obj.decrypt(enc)
 
with open(r'd:\Test\1.txt', 'rb') as f:
    e = f.read()
 
u = dec(e)
with open(r'd:\Test\1_27_2772022203247_0-4.txt', 'wb') as f:
    f.write(u)
 
def enc(enc):
    return enc_obj.encrypt(enc)
 
with open(r'd:\Test\3.txt', 'rb') as f:
    e = f.read()
 
u = enc(e)
with open(r'd:\Test\4.txt', 'wb') as f:
    f.write(u)

from Crypto.Cipher import AES
from binascii import b2a_hex, a2b_hex
 
# with open(r'd:\Test\1.txt', 'r') as f:
#     text = f.read()
#     print(text)
    # print(len(text))
 
text = 'здесьвсякаябелибердадляпримера'
#text = '003456789012345678901234567890'
 
def blok_to_16():
    if len(text.encode('utf-8')) % 16:
        add = 16 - (len(text.encode('utf-8')) % 16)
    else:
        add = 0
    new_text =  ("0" * add) + text
    print(new_text)
    print(len(new_text))
    #return new_text.encode('utf-8')
    print(new_text.encode('utf-8'))
    global _text
    _text = new_text.encode('utf-8')
    # with open(r'd:\Test\2.txt', 'wb') as f:
    #     f.write(_text)
#blok_to_16()
 
def encrypt(text):
    key = '9999999999999999'.encode('utf-8')
    mode = AES.MODE_CBC
    iv = b'1111111111111111'
    blok_to_16()
    #print('Проверка:', text)
    cryptos = AES.new(key, mode, iv)
    global cipher_text
    cipher_text = cryptos.encrypt(_text)
    #return b2a_hex(cipher_text)
    #return (cipher_text)
    print('Зашифровано:', cipher_text)
 
encrypt(text)
 
def decrypt(text):
    key = '9999999999999999'.encode('utf-8')
    iv = b'1111111111111111'
    mode = AES.MODE_CBC
    cryptos = AES.new(key, mode, iv)
    #plain_text = cryptos.decrypt(a2b_hex(cipher_text))
    plain_text = cryptos.decrypt(cipher_text)
    #return bytes.decode(plain_text).rstrip('0')
    print('Дешифровано:', plain_text)
    original = plain_text.decode('utf-8')
    print(original)
 
decrypt(text)

from Crypto.Cipher import AES
 
iv = bytes([0] * 16)
key = b'1234567890123456'
enc_obj = AES.new(key, AES.MODE_CBC, iv)
dec_obj = AES.new(key, AES.MODE_CBC, iv)
 
 
def pad(text):
    return text + (16 - len(text) % 16) * chr(16 - len(text) % 16)
 
 
def unpad(text):
    return text[0:-ord(text[-1])]
 
 
def enc(enc):
    return enc_obj.encrypt(pad(enc).encode())
 
 
def dec(enc):
    return unpad(dec_obj.decrypt(enc).decode())
 
 
with open('test-plain.txt') as f:
    plain = f.read()
 
e = enc(plain)
with open('test-enc.txt', 'wb') as f:
    f.write(e)
 
with open('test-enc.txt', 'rb') as f:
    encrypted = f.read()
 
decrypted = dec(encrypted)
with open('test-dec.txt', 'w') as f:
    f.write(decrypted)