Cleaning up input before processing it is very important (and should not be forgotten!). You can use the following script to do it very quickly:


< ?PHP
foreach ($_POST as $key => $value) {
if (empty($_POST[$key])) {$_POST[$key] = NULL;}

$_POST[$key] = addslashes($value);
}
?>


This is again just a very basic script but it will save you a load of code and does the job pretty well. If you’re doing this check within a MySQL connection I would suggest also running mysql_real_escape_string().

I must say though, I like the idea of adding a unique hash to data to verify its integrity. You could make good use of that to prevent cookie modification hacks by “checksumming” the data before populating the cookie.

Good tip