function generateGUID()
{
	$guid = '';
 
	$time_low = str_pad(dechex(mt_rand(0, 65535)), 4, '0', STR_PAD_LEFT) . str_pad(dechex(mt_rand(0, 65535)), 4, '0', STR_PAD_LEFT);
	$time_mid = str_pad(dechex(mt_rand(0, 65535)), 4, '0', STR_PAD_LEFT);
 
	$time_high_and_version = mt_rand(0, 255);
	$time_high_and_version = $time_high_and_version & hexdec('0f');
	$time_high_and_version = $time_high_and_version ^ hexdec('40');  // Sets the version number to 4 in the high byte
	$time_high_and_version = str_pad(dechex($time_high_and_version), 2, '0', STR_PAD_LEFT);
 
	$clock_seq_hi_and_reserved = mt_rand(0, 255);
	$clock_seq_hi_and_reserved = $clock_seq_hi_and_reserved & hexdec('3f');
	$clock_seq_hi_and_reserved = $clock_seq_hi_and_reserved ^ hexdec('80');  // Sets the variant for this GUID type to '10x'
	$clock_seq_hi_and_reserved = str_pad(dechex($clock_seq_hi_and_reserved), 2, '0', STR_PAD_LEFT);
 
	$clock_seq_low = str_pad(dechex(mt_rand(0, 65535)), 4, '0', STR_PAD_LEFT);
 
	$node = str_pad(dechex(mt_rand(0, 65535)), 4, '0', STR_PAD_LEFT) . str_pad(dechex(mt_rand(0, 65535)), 4, '0', STR_PAD_LEFT) . str_pad(dechex(mt_rand(0, 65535)), 4, '0', STR_PAD_LEFT);
 
	$guid = $time_low . '-' . $time_mid . '-' . $time_high_and_version . $clock_seq_hi_and_reserved . '-' . $clock_seq_low . '-' . $node;
 
	return $guid;
}