??? ??? ???? ??? ??? ?????. ?? md5 ? GUID? ?? ????? ????? ??? ???? ??? ?????? ???? ??? ???? ???? ?? ???.

? ??? ?? ??? 1? ??? ???? ???. ???? ?? ??? ? ???? ??? Unixtime ??? ???? ?????. 1?? ???? ? ??? ??? ????? ????. ??? ? ??? ????? ??? ?? ??? ??? ?? ????.

??? ??? ??? ???? ??? 0? ??? ??(??? ??) 10,000?? ??? ? 0~3?? ?? 100,000?? ???? ????. ???? ??? ?? ??? ??? ???? ??? ??? ?? ??? ??? PV? ????? ?????.

// ??? ??? ?? ?? ??

// ???, ???? 10,000?? ?? ?? ??, 0 ??, 100,000 ? 0-3 ??, ?? ??? ??? ????? ??? PV

private function genUserNumber()
{
    $chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    $username = "";
    for ( $i = 0; $i < 6; $i++ )
    {
        $username .= $chars[mt_rand(0, strlen($chars))];
    }
    return strtoupper(base_convert(time() - 1420070400, 10, 36)).$username;
}