<? 

echo generate(); 
function generate(){ 
  $Charset=array_merge(range('0','9'),range('a','z'),range('A','Z')); 
  mt_srand((double)microtime()*1000000); 
  for ($i=1;$i<=(count($Charset)*2);$i++) 
  { 
   $swap      = mt_rand(0,count($Charset)-1); 
   $tmp      = $Charset[$swap]; 
   $Charset[$swap]   = $Charset[0]; 
   $Charset[0]   = $tmp; 
  } 
  $string = implode('',$Charset).substr(md5(time()), 0, 5).implode('',$Charset).substr(md5(substr(sha1(mktime()), 0, 10)), 0, 5); 
  $ende = rand(20, strlen($string)-20); 
  $start = $ende-20; 
  return substr($string, $start, $ende); 
 } 


?>