PMA\libraries\plugins\auth\AuthenticationCookie::getIVSize PHP Method

    public function getIVSize()
    {
        if (self::useOpenSSL()) {
            return openssl_cipher_iv_length('AES-128-CBC');
        }
        $cipher = new Crypt\AES(Crypt\Base::MODE_CBC);
        return $cipher->block_size;
    }