PHP生成唯一的激活码

load->helper(array('form', 'url','base','captcha','curl')); //鍔犺浇杈呭姪鍑芥暟
        $this->load->model('db_model');
        $this->load->library('session');
      
    }
    
  public function index(){


//使用  
echo $key =$this->create_guid (); 
  }

/** 
 * 生成永远唯一的激活码 
 * @return string 
 */  
function create_guid($namespace = null) {  
    static $guid = '';  
    $uid = uniqid ( "", true );  
      
    $data = $namespace;  
    $data .= $_SERVER ['REQUEST_TIME'];     // 请求那一刻的时间戳  
    $data .= $_SERVER ['HTTP_USER_AGENT'];  // 获取访问者在用什么操作系统  
    $data .= $_SERVER ['SERVER_ADDR'];      // 服务器IP  
    $data .= $_SERVER ['SERVER_PORT'];      // 端口号  
    $data .= $_SERVER ['REMOTE_ADDR'];      // 远程IP  
    $data .= $_SERVER ['REMOTE_PORT'];      // 端口信息  
      
    $hash = strtoupper ( hash ( 'ripemd128', $uid . $guid . md5 ( $data ) ) );  
    $guid = '{' . substr ( $hash, 0, 8 ) . '-' . substr ( $hash, 8, 4 ) . '-' . substr ( $hash, 12, 4 ) . '-' . substr ( $hash, 16, 4 ) . '-' . substr ( $hash, 20, 12 ) . '}';  
      
    return $guid;  
}  
  

//记录时间  
function getmicrotime()  
{  
    list($usec, $sec) = explode(" ",microtime());  
    return ((float)$usec + (float)$sec);  
}  
  
    
}