Encrypt - Decrypt AES on PHP openssl vs Python Crypto

encrypt_aes.php

// let say key and iv is shared securely between end
// iv - encrypt method AES-256-CBC expects 16 bytes
private $secret_key = 'secret';
private $secret_iv = 'salt-secret';

function aes_encrypt($string) {
    $key = hash('sha256', $this->secret_key);
    $iv = substr(hash('sha256', $this->secret_iv), 0, 16);

    return base64_encode(openssl_encrypt($string, 'AES-256-CBC', $key, 0, $iv));
    // incase you don't want to use double encode
    // return openssl_encrypt($string, $encrypt_method, $key, 0, $iv);
}

function aes_decrypt($string) {
    $key = hash('sha256', $this->secret_key);
    $iv = substr(hash('sha256', $this->secret_iv), 0, 16);

    return openssl_decrypt(base64_decode($string), 'AES-256-CBC', $key, 0, $iv);
    // incase you don't want to use double encode
    // return openssl_decrypt($string, 'AES-256-CBC', $key, 0, $iv);
}

encrypt_aes.py

#!/usr/bin/env python3
# pip install pycrypto

import hashlib
from base64 import b64encode, b64decode
from Crypto.Cipher import AES
from Crypto.Util.Padding import pad
from Crypto.Util.Padding import unpad

# let say key and iv is shared securely between end.
# keep in mind AES supports multiple key sizes: 16 (AES128), 24 (AES192), or 32 (AES256).
# and iv - encrypt method AES-256-CBC expects 16 bytes
secret_key = 'secret'
secret_iv = 'salt-secret'

def aes_encrypt(plain_string):
  try:
    hash_key = hashlib.sha256(secret_key.encode('utf-8')).hexdigest()[:32].encode("utf-8")
    hash_iv = hashlib.sha256(secret_iv.encode('utf-8')).hexdigest()[:16].encode("utf-8")
    cipher = AES.new(hash_key, AES.MODE_CBC, hash_iv)
    return b64encode(b64encode(cipher.encrypt(pad(plain_string.encode('utf-8'), AES.block_size)))).decode('utf-8')
    # incase you don't want to use double encode
    # return b64encode(cipher.encrypt(pad(plain_string.encode('utf-8'), AES.block_size))).decode('utf-8')
  except Exception as e:
    return None
  
def aes_decrypt(plain_string):
  try:
    hash_key = hashlib.sha256(secret_key.encode('utf-8')).hexdigest()[:32].encode("utf-8")
    hash_iv = hashlib.sha256(secret_iv.encode('utf-8')).hexdigest()[:16].encode("utf-8")
    cipher = AES.new(hash_key, AES.MODE_CBC, hash_iv)
    return unpad(cipher.decrypt( b64decode( b64decode( plain_string ) ) ), AES.block_size).decode('utf-8')
    # incase you don't want to use double encode
    # return unpad(cipher.decrypt( b64decode( plain_string ) ), AES.block_size).decode('utf-8')
  except Exception as e:
    return None