Tools.php
public static function GUIDv4()
    {
        return sprintf(
            '%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
            mt_rand(0, 0xffff),
            mt_rand(0, 0xffff),
            mt_rand(0, 0xffff),
            mt_rand(0, 0x0fff) | 0x4000,
            mt_rand(0, 0x3fff) | 0x8000,
            mt_rand(0, 0xffff),
            mt_rand(0, 0xffff),
            mt_rand(0, 0xffff)
        );
    }
public static function GUIDv4()
    {
        return sprintf(
            '%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
            mt_rand(0, 0xffff),
            mt_rand(0, 0xffff),
            mt_rand(0, 0xffff),
            mt_rand(0, 0x0fff) | 0x4000,
            mt_rand(0, 0x3fff) | 0x8000,
            mt_rand(0, 0xffff),
            mt_rand(0, 0xffff),
            mt_rand(0, 0xffff)
        );
    }
Generate v4 UUID

Version 4 UUIDs are pseudo-random.

@return string GUIDv4
@static