Is it possible to remove a Password from a PDF file using PHP?

Of course it's possible, all you need to do is reverse engineer the encryption and compression and implement the reverse operations in PHP - but why bother:

<?php
   `gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=unencrypted.pdf -c .setpdfwrite -f encrypted.pdf`;
?>

C.