    /**
     * Get the specified number of random bytes using Windows'
     * randomness source via a COM object previously created by UUID::initRandom().
     * Randomness is returned as a string of bytes.
     *
     * Straight binary mysteriously doesn't work, hence the base64
     *
     * @param int $bytes
     * @return string
     */
    protected static function randomCOM ($bytes)
    {
        return base64_decode(self::$randomSource->GetRandom($bytes, 0));