Hi, I want to ask about this piece of code that is used to protect the content of some quotations inside a website. The quotations will only change once in a day, depending on the cookie on the client's browser. $ct is the counter for the quotations.
If we change the $ct and $date from the cookie, it will be checked from the cookie storing the md5 hash of $ct.$date.$password. If it doesnot match, the cookie will be reset back to 0 again. Is this implementation secure enough?

//Do the cookie stuff
   $ct = isset($_COOKIE['ct']) ? $_COOKIE['ct'] : 0;
   $date = isset($_COOKIE['date']) ? $_COOKIE['date'] : date('Ymd');
   if(isset($_COOKIE['hash']) && $_COOKIE['hash'] == md5($ct.$date.$password)) {
      if($date < date('Ymd')) {
         $ct++;
         if($ct >= count($thoughts)) $ct = count($thoughts)-1;
         $date = date('Ymd');   
      }
   }
   else {
      $ct = 0;
      $date = date('Ymd');
   }
   setcookie("hash", md5($ct.$date.$password), time()+$cookielife);
   setcookie("ct", $ct, time()+$cookielife);
   setcookie("date", $date, time()+$cookielife);

The whole code is from *ttp://www.unoriginal.org/thoughts/thought.php?action=source