public function generateSalt($length = 64)
    {
        $chars  = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
        $chars .= '!@#$%^&*()';
        $chars .= '-_ []{}<>~`+=,.;:/?|';

        $factory = new Factory();
        $generator = $factory->getGenerator(new Strength(Strength::MEDIUM));

        return $generator->generateString($length, $chars);
    }