PHP - Encrypt / Decrypt with out IV Vector with AES-256-CBC

const PASSWORD = 'abcdefghi1234567890';
const CIPHER_METHOD = 'AES-256-CBC';

function encrypt($str) {
    $val = openssl_encrypt($str, CIPHER_METHOD, hash('sha256', PASSWORD, true));
    return $val;    
}

function decrypt($str) {
   return openssl_decrypt($str, CIPHER_METHOD, hash('sha256', PASSWORD, true));
}

$plain_data = 'I am vijay';

$encrypted = encrypt($plain_data);
echo "Encrypted : ".$encrypted."

";

$decrypted = decrypt($encrypted);
echo "Decrypted : ".$decrypted."

";

?>


Output

: openssl_encrypt(): Using an empty Initialization Vector (iv) is potentially insecure and not recommended in D:\php\test.php >

Encrypted : zmuNrqZ+GwtQC5B0riJoMw==

Decrypted : I am vijay