Is it possible to remove a Password from a PDF fil

Question

I would like to ask if it's possible to use PHP in removing a password from a password-protected PDF file in which I already know the password? I've seen this page which provides many options but using bash script. :( I was required to use PHP as much as possible. Any suggestions appreciated!

Answer 1

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.